iOS开发技巧(一)

2017/06/27 iOS - 次.

iOS开发技巧(一)

1、禁止手机睡眠

[UIApplication sharedApplication].idleTimerDisabled = YES;

2、隐藏某行cell

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
// 如果是你需要隐藏的那一行,返回高度为0
    if(indexPath.row == YouWantToHideRow)
        return 0; 
    return 44;
}

// 然后再你需要隐藏cell的时候调用
[self.tableView beginUpdates];
[self.tableView endUpdates];

3、禁用button高亮

button.adjustsImageWhenHighlighted = NO;
或者在创建的时候
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

4、tableview遇到这种报错failed to obtain a cell from its dataSource

是因为你的cell被调用的早了。先循环使用了cell,后又创建cell。顺序错了

可能原因:1、xib的cell没有注册 2、内存中已经有这个cell的缓存了(也就是说通过你的cellId找到的cell并不是你想要的类型),这时候需要改下cell的标识

5、cocoa pods报这个错误:unable to access ‘https://github.com/facebook/pop.git/’: Operation timed out after 0 milliseconds with 0 out of 0 bytes received

解决办法:原因可能是网络问题,网络请求超时了,只需要重试就行了

6、cocoa pods 出现ERROR: While executing gem … (Errno::EPERM)

解决办法:https://segmentfault.com/q/1010000002926243

7、动画切换window的根控制器

// options是动画选项
[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:0.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
        BOOL oldState = [UIView areAnimationsEnabled];
        [UIView setAnimationsEnabled:NO];
        [UIApplication sharedApplication].keyWindow.rootViewController = [RootViewController new];
        [UIView setAnimationsEnabled:oldState];
    } completion:^(BOOL finished) {
    }];

8、去除数组中重复的对象

NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];

9、编译的时候遇到 no such file or directory: /users/apple/XXX

是因为编译的时候,在此路径下找不到这个文件,解决这个问题,首先是是要检查缺少的文件是不是在工程中,如果不在工程中,需要从本地拖进去,如果发现已经存在工程中了,或者拖进去还是报错,这时候需要去build phases中搜索这个文件,这时候很可能会搜出现两个相同的文件,这时候,有一个路径是正确的,删除另外一个即可。如果删除了还是不行,需要把两个都删掉,然后重新往工程里拖进这个文件即可

img

10、iOS8系统中,tableView最好实现下-tableView: heightForRowAtIndexPath:这个代理方法,要不然在iOS8中可能就会出现显示不全或者无法响应事件的问题

11、iOS8中实现侧滑功能的时候这个方法必须实现,要不然在iOS8中无法侧滑

// 必须写的方法,和editActionsForRowAtIndexPath配对使用,里面什么不写也行
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

}

12、三个通知

NSSystemTimeZoneDidChangeNotification监听修改时间界面的两个按钮状态变化
UIApplicationSignificantTimeChangeNotification 监听用户改变时间 (只要点击自动设置按钮就会调用) 
NSSystemClockDidChangeNotification 监听用户修改时间(时间不同才会调用)

13、SDWebImage本地缓存有时候会害人。如果之前缓存过一张图片,即使下次服务器换了这张图片,但是图片url没换,用sdwebimage下载下来的还是以前那张,所以遇到这种问题,不要先去怼服务器,清空下缓存再试就好了。

14、上线前注意:

1)、删掉代码中所有的测试代码

2)、如果后台有审核模式,提醒后台开启此模式

3)、主流程再跑一跑

4)、全局搜索waring,检查所有标记waring的地方

15、跳进app权限设置

// 跳进app设置
if (UIApplicationOpenSettingsURLString != NULL) {

     NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
    [[UIApplication sharedApplication] openURL:url];
}

16、给一个view截图

UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

17、开发中如果要动态修改tableView的tableHeaderView或者tableFooterView的高度,需要给tableView重新设置,而不是直接更改高度。正确的做法是重新设置一下tableView.tableFooterView = 更改过高度的view。为什么?其实在iOS8以上直接改高度是没有问题的,在iOS8中出现了contentSize不准确的问题,这是解决办法。

18、注意对象为nil的时候,调用此对象分类的方法不会执行

19、collectionView的内容小于其宽高的时候是不能滚动的,设置可以滚动:

collectionView.alwaysBounceHorizontal = YES;
collectionView.alwaysBounceVertical = YES;

20、设置navigationBar上的title颜色和大小

[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]

21、颜色转图片

+ (UIImage *)cl_imageWithColor:(UIColor *)color {
  CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
  UIGraphicsBeginImageContext(rect.size);
  CGContextRef context = UIGraphicsGetCurrentContext();

  CGContextSetFillColorWithColor(context, [color CGColor]);
  CGContextFillRect(context, rect);

  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  return image;
}

22、view设置圆角

#define ViewBorderRadius(View, Radius, Width, Color)\
\
[View.layer setCornerRadius:(Radius)];\
[View.layer setMasksToBounds:YES];\
[View.layer setBorderWidth:(Width)];\
[View.layer setBorderColor:[Color CGColor]] // view圆角

23、强/弱引用

#define WeakSelf(type)  __weak typeof(type) weak##type = type; // weak
#define StrongSelf(type)  __strong typeof(type) type = weak##type; // strong

24、由角度转换弧度

#define DegreesToRadian(x) (M_PI * (x) / 180.0)

25、由弧度转换角度

#define RadianToDegrees(radian) (radian*180.0)/(M_PI)

26、获取图片资源

#define GetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]

27、获取temp

#define PathTemp NSTemporaryDirectory()

28、获取沙盒 Document

#define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]

29、获取沙盒 Cache

#define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]

30、GCD代码只执行一次

#define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);

31、自定义NSLog

#ifdef DEBUG
#define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
#else
#define NSLog(...)
#endif

32、Font

#define FontL(s)             [UIFont systemFontOfSize:s weight:UIFontWeightLight]
#define FontR(s)             [UIFont systemFontOfSize:s weight:UIFontWeightRegular]
#define FontB(s)             [UIFont systemFontOfSize:s weight:UIFontWeightBold]
#define FontT(s)             [UIFont systemFontOfSize:s weight:UIFontWeightThin]
#define Font(s)              FontL(s)

33、FORMAT

#define FORMAT(f, ...)      [NSString stringWithFormat:f, ## __VA_ARGS__]

34、在主线程上运行

#define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);

35、开启异步线程

#define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);

36、通知

#define NOTIF_ADD(n, f)     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]
#define NOTIF_POST(n, o)    [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]
#define NOTIF_REMV()        [[NSNotificationCenter defaultCenter] removeObserver:self]

37、随机颜色

+ (UIColor *)RandomColor {
    NSInteger aRedValue = arc4random() % 255;
    NSInteger aGreenValue = arc4random() % 255;
    NSInteger aBlueValue = arc4random() % 255;
    UIColor *randColor = [UIColor colorWithRed:aRedValue / 255.0f green:aGreenValue / 255.0f blue:aBlueValue / 255.0f alpha:1.0f];
    return randColor;
}

38、获取window

+(UIWindow*)getWindow {
    UIWindow* win = nil; //[UIApplication sharedApplication].keyWindow;
    for (id item in [UIApplication sharedApplication].windows) {
        if ([item class] == [UIWindow class]) {
            if (!((UIWindow*)item).hidden) {
                win = item;
                break;
            }
        }
    }
    return win;
}

39、修改textField的placeholder的字体颜色、大小

[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
[textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

40、统一收起键盘

[[[UIApplication sharedApplication] keyWindow] endEditing:YES];

41、控制屏幕旋转,在控制器中写

/** 是否支持自动转屏 */
- (BOOL)shouldAutorotate {
    return YES;
}

/** 支持哪些屏幕方向 */
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;
}

/** 默认的屏幕方向(当前ViewController必须是通过模态出来的UIViewController(模态带导航的无效)方式展现出来的,才会调用这个方法) */
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
    return UIInterfaceOrientationLandscapeLeft | UIInterfaceOrientationLandscapeRight;
}

42、获取app缓存大小

- (CGFloat)getCachSize {

    NSUInteger imageCacheSize = [[SDImageCache sharedImageCache] getSize];
    //获取自定义缓存大小
    //用枚举器遍历 一个文件夹的内容
    //1.获取 文件夹枚举器
    NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];
    NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:myCachePath];
    __block NSUInteger count = 0;
    //2.遍历
    for (NSString *fileName in enumerator) {
        NSString *path = [myCachePath stringByAppendingPathComponent:fileName];
        NSDictionary *fileDict = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];
        count += fileDict.fileSize;//自定义所有缓存大小
    }
    // 得到是字节  转化为M
    CGFloat totalSize = ((CGFloat)imageCacheSize+count)/1024/1024;
    return totalSize;
}

43、清理app缓存

- (void)handleClearView {
    //删除两部分
    //1.删除 sd 图片缓存
    //先清除内存中的图片缓存
    [[SDImageCache sharedImageCache] clearMemory];
    //清除磁盘的缓存
    [[SDImageCache sharedImageCache] clearDisk];
    //2.删除自己缓存
    NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];
    [[NSFileManager defaultManager] removeItemAtPath:myCachePath error:nil];
}

44、模型转字典

static NSSet *classes;

- (NSMutableDictionary *)getParameterDictionary {

    NSMutableDictionary *dict = [NSMutableDictionary dictionary];

    Class c = self.class;

    while (c) {
        unsigned count;
        objc_property_t *properties = class_copyPropertyList([c class], &count);

        for (int i = 0; i < count; i++) {
            NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
            dict[key] = [self valueForKey:key];
        }
        free(properties);

        // 获得父类
        c = class_getSuperclass(c);

        if ([self isClassFromFoundation:c]) break;
    }
    return dict;
}

- (BOOL)isClassFromFoundation:(Class)c
{
    if (c == [NSObject class] || c == [NSManagedObject class]) return YES;

    __block BOOL result = NO;
    [[self foundationClasses] enumerateObjectsUsingBlock:^(Class foundationClass, BOOL *stop) {
        if ([c isSubclassOfClass:foundationClass]) {
            result = YES;
            *stop = YES;
        }
    }];
    return result;
}

- (NSSet *)foundationClasses
{
    if (classes == nil) {
        // 集合中没有NSObject,因为几乎所有的类都是继承自NSObject,具体是不是NSObject需要特殊判断
        classes = [NSSet setWithObjects:
                              [NSURL class],
                              [NSDate class],
                              [NSValue class],
                              [NSData class],
                              [NSError class],
                              [NSArray class],
                              [NSDictionary class],
                              [NSString class],
                              [NSAttributedString class], nil];
    }
    return classes;
}

45、交换两个方法实现

Class aClass = [self class]; 

        SEL originalSelector = @selector(viewWillAppear:); 
        SEL swizzledSelector = @selector(xxx_viewWillAppear:); 

        Method originalMethod = class_getInstanceMethod(aClass, originalSelector); 
        Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector); 

        BOOL didAddMethod = 
            class_addMethod(aClass, 
                originalSelector, 
                method_getImplementation(swizzledMethod), 
                method_getTypeEncoding(swizzledMethod)); 

        if (didAddMethod) { 
            class_replaceMethod(aClass, 
                swizzledSelector, 
                method_getImplementation(originalMethod), 
                method_getTypeEncoding(originalMethod)); 
        } else { 
            method_exchangeImplementations(originalMethod, swizzledMethod); 
        }

46、打印百分号和引号

NSLog(@"%%");
NSLog(@"\"");

47、几个常用权限判断

if ([CLLocationManager authorizationStatus] ==kCLAuthorizationStatusDenied) {
    NSLog(@"没有定位权限");
}
AVAuthorizationStatus statusVideo = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
if (statusVideo == AVAuthorizationStatusDenied) {
    NSLog(@"没有摄像头权限");
}
//是否有麦克风权限
AVAuthorizationStatus statusAudio = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];
if (statusAudio == AVAuthorizationStatusDenied) {
    NSLog(@"没有录音权限");
}
[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
    if (status == PHAuthorizationStatusDenied) {
        NSLog(@"没有相册权限");
    }
}];

48、获取手机型号

+ (NSString *)getDeviceInfo {
struct utsname systemInfo;
uname(&systemInfo);
NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSASCIIStringEncoding];
if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";
if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";
if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";
if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";
if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c";
if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c";
if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s";
if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s";
if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus";
if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6";
if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";
if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";
// 日行两款手机型号均为日本独占,可能使用索尼FeliCa支付方案而不是苹果支付
if ([platform isEqualToString:@"iPhone9,1"])    return @"国行、日版、港行iPhone 7";
if ([platform isEqualToString:@"iPhone9,2"])    return @"港行、国行iPhone 7 Plus";
if ([platform isEqualToString:@"iPhone9,3"])    return @"美版、台版iPhone 7";
if ([platform isEqualToString:@"iPhone9,4"])    return @"美版、台版iPhone 7 Plus";
if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";
if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";
if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";
if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";
if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";
if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";
if ([platform isEqualToString:@"iPad1,1"]) return @"iPad 1G";
if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad4,1"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,2"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,3"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,4"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"iPad4,5"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"iPad4,6"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"i386"]) return @"iPhone Simulator";
if ([platform isEqualToString:@"x86_64"]) return @"iPhone Simulator";
return platform;
}

49、长按复制功能

- (void)viewDidLoad
{
    [self.view addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(pasteBoard:)]];
}
- (void)pasteBoard:(UILongPressGestureRecognizer *)longPress {
    if (longPress.state == UIGestureRecognizerStateBegan) {
        UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
        pasteboard.string = @"需要复制的文本";
    }
}

50、cocoapods升级

在终端执行 sudo gem install -n / usr / local / bin cocoapods –pre

51、设置启动页后,依然显示之前的

删除app,手机重启,重新安装

52、判断图片类型

//通过图片Data数据第一个字节 来获取图片扩展名
- (NSString *)contentTypeForImageData:(NSData *)data
{
    uint8_t c;
    [data getBytes:&c length:1];
    switch (c)
    {
        case 0xFF:
            return @"jpeg";

        case 0x89:
            return @"png";

        case 0x47:
            return @"gif";

        case 0x49:
        case 0x4D:
            return @"tiff";

        case 0x52:
        if ([data length] < 12) {
            return nil;
        }

        NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];
        if ([testString hasPrefix:@"RIFF"]
            && [testString hasSuffix:@"WEBP"])
        {
            return @"webp";
        }

        return nil;
    }

    return nil;
}

53、获取手机和app信息

NSDictionary infoDictionary = [[NSBundle mainBundle] infoDictionary]; ​ CFShow(infoDictionary); // app名称 ​ NSString *appName = [infoDictionary objectForKey:@”CFBundleDisplayName”]; // app版本 ​ NSString *app*Version = [infoDictionary objectForKey:@”CFBundleShortVersionString”]; // app build版本 ​ NSString *app_build = [infoDictionary objectForKey:@”CFBundleVersion”];

//手机序列号 ​ NSString* identifierNumber = [[UIDevice currentDevice] uniqueIdentifier]; ​ NSLog(@”手机序列号: %@”,identifierNumber); //手机别名: 用户定义的名称 ​ NSString* userPhoneName = [[UIDevice currentDevice] name]; ​ NSLog(@”手机别名: %@”, userPhoneName); //设备名称 ​ NSString* deviceName = [[UIDevice currentDevice] systemName]; ​ NSLog(@”设备名称: %@”,deviceName ); //手机系统版本 ​ NSString* phoneVersion = [[UIDevice currentDevice] systemVersion]; ​ NSLog(@”手机系统版本: %@”, phoneVersion); //手机型号 ​ NSString* phoneModel = [[UIDevice currentDevice] model]; ​ NSLog(@”手机型号: %@”,phoneModel ); //地方型号 (国际化区域名称) ​ NSString* localPhoneModel = [[UIDevice currentDevice] localizedModel]; ​ NSLog(@”国际化区域名称: %@”,localPhoneModel );

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary]; // 当前应用名称 ​ NSString *appCurName = [infoDictionary objectForKey:@”CFBundleDisplayName”]; ​ NSLog(@”当前应用名称:%@”,appCurName); // 当前应用软件版本 比如:1.0.1 ​ NSString *appCurVersion = [infoDictionary objectForKey:@”CFBundleShortVersionString”]; ​ NSLog(@”当前应用软件版本:%@”,appCurVersion); // 当前应用版本号码 int类型 ​ NSString *appCurVersionNum = [infoDictionary objectForKey:@”CFBundleVersion”]; ​ NSLog(@”当前应用版本号码:%@”,appCurVersionNum);

54、获取一个类的所有属性

id LenderClass = objc_getClass("Lender");
unsigned int outCount, i;
objc_property_t *properties = class_copyPropertyList(LenderClass, &outCount);
for (i = 0; i < outCount; i++) {
    objc_property_t property = properties[i];
    fprintf(stdout, "%s %s\n", property_getName(property), property_getAttributes(property));
}

55、image圆角

- (UIImage *)circleImage{
    // NO代表透明
    UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);
    // 获得上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    // 添加一个圆
    CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
    // 方形变圆形
    CGContextAddEllipseInRect(ctx, rect);
    // 裁剪
    CGContextClip(ctx);
    // 将图片画上去
    [self drawInRect:rect];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

56、image拉伸

+ (UIImage *)resizableImage:(NSString *)imageName
{
    UIImage *image = [UIImage imageNamed:imageName];
    CGFloat imageW = image.size.width;
    CGFloat imageH = image.size.height;
    return [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageH * 0.5, imageW * 0.5, imageH * 0.5, imageW * 0.5) resizingMode:UIImageResizingModeStretch];
}

57、JSON字符串转字典

+ (NSDictionary *)parseJSONStringToNSDictionary:(NSString *)JSONString {
    NSData *JSONData = [JSONString dataUsingEncoding:NSUTF8StringEncoding];
    NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableLeaves error:nil];
    return responseJSON;
}

58、身份证号验证

- (BOOL)validateIdentityCard {
    BOOL flag;
    if (self.length <= 0) {
        flag = NO;
        return flag;
    }
    NSString *regex2 = @"^(\\d{14}|\\d{17})(\\d|[xX])$";
    NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];
    return [identityCardPredicate evaluateWithObject:self];
}

59、获取设备mac地址

+ (NSString *)macAddress {
    int                 mib[6];
    size_t              len;
    char                *buf;
    unsigned char       *ptr;
    struct if_msghdr    *ifm;
    struct sockaddr_dl  *sdl;

    mib[0] = CTL_NET;
    mib[1] = AF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_LINK;
    mib[4] = NET_RT_IFLIST;

    if((mib[5] = if_nametoindex("en0")) == 0) {
        printf("Error: if_nametoindex error\n");
        return NULL;
    }

    if(sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 1\n");
        return NULL;
    }

    if((buf = malloc(len)) == NULL) {
        printf("Could not allocate memory. Rrror!\n");
        return NULL;
    }

    if(sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 2");
        return NULL;
    }

    ifm = (struct if_msghdr *)buf;
    sdl = (struct sockaddr_dl *)(ifm + 1);
    ptr = (unsigned char *)LLADDR(sdl);
    NSString *outstring = [NSString stringWithFormat:@"X:X:X:X:X:X",
                           *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
    free(buf);

    return outstring;
}

60、导入自定义字体库

1、找到你想用的字体的 ttf 格式,拖入工程

2、在工程的plist中增加一行数组,“Fonts provided by application”

3、为这个key添加一个item,value为你刚才导入的ttf文件名

4、直接使用即可:label.font = [UIFont fontWithName:@”你刚才导入的ttf文件名” size:20.0];

61、拿到当前正在显示的控制器,不管是push进去的,还是present进去的都能拿到

- (UIViewController *)getVisibleViewControllerFrom:(UIViewController*)vc {
    if ([vc isKindOfClass:[UINavigationController class]]) {
        return [self getVisibleViewControllerFrom:[((UINavigationController*) vc) visibleViewController]];
    }else if ([vc isKindOfClass:[UITabBarController class]]){
        return [self getVisibleViewControllerFrom:[((UITabBarController*) vc) selectedViewController]];
    } else {
        if (vc.presentedViewController) {
            return [self getVisibleViewControllerFrom:vc.presentedViewController];
        } else {
            return vc;
        }
    }
}

62、runtime为一个类动态添加属性

// 动态添加属性的本质是: 让对象的某个属性与值产生关联
        objc_setAssociatedObject(self, WZBPlaceholderViewKey, placeholderView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

63、获取runtime为一个类动态添加的属性

objc_getAssociatedObject(self, WZBPlaceholderViewKey);

64、KVO监听某个对象的属性

// 添加监听者
[self addObserver:self forKeyPath:property options:NSKeyValueObservingOptionNew context:nil];

// 当监听的属性值变化的时候会来到这个方法
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if ([keyPath isEqualToString:@"property"]) {
       [self textViewTextChange];
       } else {
     }
}

65、Reachability判断网络状态

NetworkStatus status = [[Reachability reachabilityForInternetConnection] currentReachabilityStatus];
    if (status == NotReachable) {
        NSLog(@"当前设备无网络");
    }
    if (status == ReachableViaWiFi) {
        NSLog(@"当前wifi网络");
    }
    if (status == NotReachable) {
        NSLog(@"当前蜂窝移动网络");
    }

66、AFNetworking监听网络状态

// 监听网络状况
    AFNetworkReachabilityManager *mgr = [AFNetworkReachabilityManager sharedManager];
    [mgr setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case AFNetworkReachabilityStatusUnknown:
                break;
            case AFNetworkReachabilityStatusNotReachable: {
                [SVProgressHUD showInfoWithStatus:@"当前设备无网络"];
            }
                break;
            case AFNetworkReachabilityStatusReachableViaWiFi:
                [SVProgressHUD showInfoWithStatus:@"当前Wi-Fi网络"];
                break;
            case AFNetworkReachabilityStatusReachableViaWWAN:
                [SVProgressHUD showInfoWithStatus:@"当前蜂窝移动网络"];
                break;
            default:
                break;
        }
    }];
    [mgr startMonitoring];

67、透明颜色不影响子视图透明度

[UIColor colorWithRed: green: blue: alpha:];

68、取图片某一点的颜色

if (point.x < 0 || point.y < 0) return nil;

CGImageRef imageRef = self.CGImage;
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
if (point.x >= width || point.y >= height) return nil;

unsigned char *rawData = malloc(height * width * 4);
if (!rawData) return nil;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData,
                                             width,
                                             height,
                                             bitsPerComponent,
                                             bytesPerRow,
                                             colorSpace,
                                             kCGImageAlphaPremultipliedLast
                                             | kCGBitmapByteOrder32Big);
if (!context) {
    free(rawData);
    return nil;
}
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);

int byteIndex = (bytesPerRow * point.y) + point.x * bytesPerPixel;
CGFloat red   = (rawData[byteIndex]     * 1.0) / 255.0;
CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;
CGFloat blue  = (rawData[byteIndex + 2] * 1.0) / 255.0;
CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;

UIColor *result = nil;
result = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
free(rawData);
return result;

69、判断该图片是否有透明度通道

  - (BOOL)hasAlphaChannel
{
    CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);
    return (alpha == kCGImageAlphaFirst ||
            alpha == kCGImageAlphaLast ||
            alpha == kCGImageAlphaPremultipliedFirst ||
            alpha == kCGImageAlphaPremultipliedLast);
}

70、获得灰度图

+ (UIImage*)covertToGrayImageFromImage:(UIImage*)sourceImage
{
    int width = sourceImage.size.width;
    int height = sourceImage.size.height;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);
    CGColorSpaceRelease(colorSpace);

    if (context == NULL) {
        return nil;
    }

    CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);
    CGImageRef contextRef = CGBitmapContextCreateImage(context);
    UIImage *grayImage = [UIImage imageWithCGImage:contextRef];
    CGContextRelease(context);
    CGImageRelease(contextRef);

    return grayImage;
}

71、根据bundle中的文件名读取图片

   + (UIImage *)imageWithFileName:(NSString *)name {
    NSString *extension = @"png";

    NSArray *components = [name componentsSeparatedByString:@"."];
    if ([components count] >= 2) {
        NSUInteger lastIndex = components.count - 1;
        extension = [components objectAtIndex:lastIndex];

        name = [name substringToIndex:(name.length-(extension.length+1))];
    }

    // 如果为Retina屏幕且存在对应图片,则返回Retina图片,否则查找普通图片
    if ([UIScreen mainScreen].scale == 2.0) {
        name = [name stringByAppendingString:@"@2x"];

        NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];
        if (path != nil) {
            return [UIImage imageWithContentsOfFile:path];
        }
    }

    if ([UIScreen mainScreen].scale == 3.0) {
        name = [name stringByAppendingString:@"@3x"];

        NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];
        if (path != nil) {
            return [UIImage imageWithContentsOfFile:path];
        }
    }

    NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];
    if (path) {
        return [UIImage imageWithContentsOfFile:path];
    }

    return nil;
}

72、合并两个图片

+ (UIImage*)mergeImage:(UIImage*)firstImage withImage:(UIImage*)secondImage {
    CGImageRef firstImageRef = firstImage.CGImage;
    CGFloat firstWidth = CGImageGetWidth(firstImageRef);
    CGFloat firstHeight = CGImageGetHeight(firstImageRef);
    CGImageRef secondImageRef = secondImage.CGImage;
    CGFloat secondWidth = CGImageGetWidth(secondImageRef);
    CGFloat secondHeight = CGImageGetHeight(secondImageRef);
    CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));
    UIGraphicsBeginImageContext(mergedSize);
    [firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];
    [secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

73、根据bundle中的图片名创建imageview

+ (id)imageViewWithImageNamed:(NSString*)imageName
{
    return [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
}

74、为imageView添加倒影

CGRect frame = self.frame;
frame.origin.y += (frame.size.height + 1);

UIImageView *reflectionImageView = [[UIImageView alloc] initWithFrame:frame];
self.clipsToBounds = TRUE;
reflectionImageView.contentMode = self.contentMode;
[reflectionImageView setImage:self.image];
reflectionImageView.transform = CGAffineTransformMakeScale(1.0, -1.0);

CALayer *reflectionLayer = [reflectionImageView layer];

CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.bounds = reflectionLayer.bounds;
gradientLayer.position = CGPointMake(reflectionLayer.bounds.size.width / 2, reflectionLayer.bounds.size.height * 0.5);
gradientLayer.colors = [NSArray arrayWithObjects:
                        (id)[[UIColor clearColor] CGColor],
                        (id)[[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.3] CGColor], nil];

gradientLayer.startPoint = CGPointMake(0.5,0.5);
gradientLayer.endPoint = CGPointMake(0.5,1.0);
reflectionLayer.mask = gradientLayer;

[self.superview addSubview:reflectionImageView];

75、画水印

// 画水印
- (void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect
{
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)
    {
        UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);
    }
    //原图
    [image drawInRect:self.bounds];
    //水印图
    [mark drawInRect:rect];
    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    self.image = newPic;
}

76、让label的文字内容显示在左上/右上/左下/右下/中心顶/中心底部

自定义UILabel
// 重写label的textRectForBounds方法
- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
    CGRect rect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];
    switch (self.textAlignmentType) {
        case WZBTextAlignmentTypeLeftTop: {
            rect.origin = bounds.origin;
        }
            break;
        case WZBTextAlignmentTypeRightTop: {
            rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, bounds.origin.y);
        }
            break;
        case WZBTextAlignmentTypeLeftBottom: {
            rect.origin = CGPointMake(bounds.origin.x, CGRectGetMaxY(bounds) - rect.size.height);
        }
            break;
        case WZBTextAlignmentTypeRightBottom: {
            rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, CGRectGetMaxY(bounds) - rect.size.height);
        }
            break;
        case WZBTextAlignmentTypeTopCenter: {
            rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - rect.origin.y);
        }
            break;
        case WZBTextAlignmentTypeBottomCenter: {
            rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - CGRectGetMaxY(bounds) - rect.size.height);
        }
            break;
        case WZBTextAlignmentTypeLeft: {
            rect.origin = CGPointMake(0, rect.origin.y);
        }
            break;
        case WZBTextAlignmentTypeRight: {
            rect.origin = CGPointMake(rect.origin.x, 0);
        }
            break;
        case WZBTextAlignmentTypeCenter: {
            rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, (CGRectGetHeight(bounds) - CGRectGetHeight(rect)) / 2);
        }
            break;
        default:
            break;
    }
    return rect;
}
- (void)drawTextInRect:(CGRect)rect {
    CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];
    [super drawTextInRect:textRect];
}

77、scrollView上的输入框,键盘挡住的问题

推荐用IQKeyboardManager这个框架!手动解决如下

1、监听键盘弹出/消失的通知2、在通知中加入代码:

    NSDictionary* info = [aNotification userInfo];
    CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];
    CGSize kbSize =keyPadFrame.size;
    CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];
    CGRect aRect = self.view.bounds;
    aRect.size.height -= (kbSize.height);

    CGPoint origin =  activeRect.origin;
    origin.y -= backScrollView.contentOffset.y;
    if (!CGRectContainsPoint(aRect, origin)) {
        CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));
        [backScrollView setContentOffset:scrollPoint animated:YES];
    }

78、frame布局的cell动态高度

这种通常在你的模型中添加一个辅助属性cellHeight,在模型中重写这个属性的get方法,根据你的布局和模型中的其他属性值计算出总高度。最后在tableView:heightForRow方法中,根据indexPath找出对应的模型,返回这个高度即可。

79、AutoLayout布局的cell动态高度

// 1、设置tableView的属性

    self.tableView.rowHeight = UITableViewAutomaticDimension;
    self.tableView.estimatedRowHeight = 44.0; // 这个属性非0,估计cell高度

// 2、至上而下设置cell的约束,注意,上下左右最好都要顶到cell的四周

img

80、使用performSelector:调用函数,内存泄漏问题

当我们在开发中使用[obj performSelector:NSSelectorFromString(@”aMethod”)];这类方法时可能会收到一个警告”performSelector may cause a leak because its selector is unknown”.

是因为编译器不清楚这个对象能不能相应这个方法,如果不能,则是不安全的,而且编译器也不清楚该怎么处理这个方法的返回值!

使用以下代码调用即可:

if (! obj) { return; }
SEL selector = NSSelectorFromString(@"aMethod");
IMP imp = [obj methodForSelector:selector];
void (*func)(id, SEL) = (void *)imp;
func(obj, selector);

或者:
SEL selector = NSSelectorFromString(@"aMethod");
((void (*)(id, SEL))[obj methodForSelector:selector])(obj, selector);

81、一个字符串是否包含另一个字符串

// 方法1
if ([str1 containsString:str2]) {
        NSLog(@"str1包含str2");
    } else {
        NSLog(@"str1不包含str2");
    }

// 方法2
if ([str1 rangeOfString: str2].location == NSNotFound) {
        NSLog(@"str1包含str2");
    } else {
        NSLog(@"str1不包含str2");
    }

82、cell去除选中效果

cell.selectionStyle = UITableViewCellSelectionStyleNone;

83、cell点按效果

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

84、当删除一个从xib拖出来的属性时,一定记得把xib中对应的线也删掉,不然会报类似[setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key的crash

img

点击这个叉号删除

85、真机测试的时候报错:Could not launch “你的 App”,process launch failed: Security

因为你的app没有上线,iOS9开始,需要手动信任Xcode生成的描述文件,打开手机设置->通用->描述文件->点击你的app的描述文件->点击信任

86、真机测试的时候报错:Could not find Developer Disk Image

这是因为你的设备系统版本大于Xcode能兼容的系统版本,比如你的设备是iOS10.3,而Xcode版本是8.2(Xcode8.2最大兼容iOS10.2),就会报这个错误。解决办法就是升级Xcode!

87、UITextView没有placeholder的问题?

网上有很多此类自定义控件,也可以参考下我写的一个UITextView分类 UITextView-WZB

88、移除字符串中的空格和换行

+ (NSString *)removeSpaceAndNewline:(NSString *)str {
    NSString *temp = [str stringByReplacingOccurrencesOfString:@" " withString:@""];
    temp = [temp stringByReplacingOccurrencesOfString:@"\r" withString:@""];
    temp = [temp stringByReplacingOccurrencesOfString:@"\n" withString:@""];
    return temp;
}

89、判断字符串中是否有空格

+ (BOOL)isBlank:(NSString *)str {
    NSRange _range = [str rangeOfString:@" "];
    if (_range.location != NSNotFound) {
        //有空格
        return YES;
    } else {
        //没有空格
        return NO;
    }
}

90、获取一个视频的第一帧图片

NSURL *url = [NSURL URLWithString:filepath];
AVURLAsset *asset1 = [[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *generate1 = [[AVAssetImageGenerator alloc] initWithAsset:asset1];
generate1.appliesPreferredTrackTransform = YES;
NSError *err = NULL;
CMTime time = CMTimeMake(1, 2);
CGImageRef oneRef = [generate1 copyCGImageAtTime:time actualTime:NULL error:&err];
UIImage *one = [[UIImage alloc] initWithCGImage:oneRef];

return one;

91、获取视频的时长

+ (NSInteger)getVideoTimeByUrlString:(NSString *)urlString {
    NSURL *videoUrl = [NSURL URLWithString:urlString];
    AVURLAsset *avUrl = [AVURLAsset assetWithURL:videoUrl];
    CMTime time = [avUrl duration];
    int seconds = ceil(time.value/time.timescale);
    return seconds;
}

92、字符串是否为空

+ (BOOL)isEqualToNil:(NSString *)str {
    return str.length <= 0 || [str isEqualToString:@""] || !str;
}

93、将app上传到App Store的时候通常会遇到这个问题

img

try again

很多人说这事苹果爸爸服务器问题,重复尝试几次,总会成功的!

但是经过尝试发现如果使用Application Loader上传成功率就非常高,所以还是推荐把ipa文件导出直接用Application Loader上传。

如果Application Loader也不行,需要检查下自己的网络,有时候vpn也会提高速度。

94、当tableView占不满一屏时,去除下边多余的单元格

self.tableView.tableHeaderView = [UIView new];
self.tableView.tableFooterView = [UIView new];

95、isKindOfClass和isMemberOfClass的区别

isKindOfClass可以判断某个对象是否属于某个类,或者这个类的子类。isMemberOfClass更加精准,它只能判断这个对象类型是否为这个类(不能判断子类)

96、__block

当一个局部变量需要在block里改变时,需要在定义时加上_block修饰,具体请看官方文档 http://developer.apple.com/library/ios/documentation/cocoa/Conceptual/Blocks/Articles/bxVariables.html #//appleref/doc/uid/TP40007502-CH6-SW6

97、-[ViewController aMethod:]: unrecognized selector sent to instance 0x7fe91e607fb0

这是一个经典错误,ViewController不能响应aMethod这个方法,错误原因可能viewController文件中没有实现aMethod这个方法

98、UITableView () failed to obtain a cell from its dataSource ()

这个错误原因是tableView的代理方法-tableView:cellForRowAtIndexPath:需要返回一个UITableViewCell,而你返回了一个nil。另外这个地方返回值不是UITableViewCell类型也会导致崩溃

99、约束如何做UIView动画?

1、把需要改的约束Constraint拖条线出来,成为属性

2、在需要动画的地方加入代码,改变此属性的constant属性

3、开始做UIView动画,动画里边调用layoutIfNeeded方法

@property (weak, nonatomic) IBOutlet NSLayoutConstraint *buttonTopConstraint;
self.buttonTopConstraint.constant = 100;
    [UIView animateWithDuration:.5 animations:^{
        [self.view layoutIfNeeded];
    }];

100、从NSURL中拿到链接字符串

NSString *urlString = myURL.absoluteString;

101、将tableView滚动到顶部

[tableView setContentOffset:CGPointZero animated:YES];
或者
[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];

102、如果用addTarget:action:forControlEvents:方法为一个button添加了很多点击事件,在某个时刻想一次删除怎么办?只需要调用下边这句代码

[youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents];

103、某个字体的高度

font.lineHeight;

104、删除某个view所有的子视图

[[someView subviews]
 makeObjectsPerformSelector:@selector(removeFromSuperview)];

105、删除NSUserDefaults所有记录

//方法一
  NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
 [[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];   
 //方法二  
- (void)resetDefaults {   
  NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
     NSDictionary * dict = [defs dictionaryRepresentation];
     for (id key in dict) {
          [defs removeObjectForKey:key];
     }
      [defs synchronize];
 }
// 方法三
[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];

106、禁用系统滑动返回功能

- (void)viewDidAppear:(BOOL)animated
{
     [super viewDidAppear:animated];
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = self;
    }
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = nil;
    }
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
     return NO;
}

107、模拟器报错

img

模拟器报错

解决办法:

打开模拟器->Simulator->Reset Content and Settings…

如果不行,就重启试试!

108、自定义cell选中背景颜色

UIView *bgColorView = [[UIView alloc] init];
bgColorView.backgroundColor = [UIColor redColor];
[cell setSelectedBackgroundView:bgColorView];

109、UILabel设置内边距

子类化UILabel,重写drawTextInRect方法

- (void)drawTextInRect:(CGRect)rect {
    // 边距,上左下右
    UIEdgeInsets insets = {0, 5, 0, 5};
    [super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];
}

110、UILabel设置文字描边

子类化UILabel,重写drawTextInRect方法

- (void)drawTextInRect:(CGRect)rect{
    CGContextRef c = UIGraphicsGetCurrentContext();
    // 设置描边宽度
    CGContextSetLineWidth(c, 1);
    CGContextSetLineJoin(c, kCGLineJoinRound);
    CGContextSetTextDrawingMode(c, kCGTextStroke);
    // 描边颜色
    self.textColor = [UIColor redColor];
    [super drawTextInRect:rect];
    // 文本颜色
    self.textColor = [UIColor yellowColor];
    CGContextSetTextDrawingMode(c, kCGTextFill);
    [super drawTextInRect:rect];
}

111、使用模拟器截图

快捷键command + s
或者File->Save Screen Shot

112、scrollView滚动到最下边

CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height);
[scrollView setContentOffset:bottomOffset animated:YES];

113、UIView背景颜色渐变

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
[self.view addSubview:view];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[view.layer insertSublayer:gradient atIndex:0];

114、停止UIView动画

[yourView.layer removeAllAnimations]

115、为UIView某个角添加圆角

// 左上角和右下角添加圆角
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(20, 20)];
    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = view.bounds;
    maskLayer.path = maskPath.CGPath;
    view.layer.mask = maskLayer;

116、删除Xcode Derived data缓存数据

依次点击Xcode -> Preferences -> location,然后点击 Derived data路径后到小箭头,删除这个文件夹下的数据就可以了,如图

img

Xcode Derived data

117、将一个view放置在其兄弟视图的最上面

[parentView bringSubviewToFront:yourView]

118、将一个view放置在其兄弟视图的最下面

[parentView sendSubviewToBack:yourView]

119、让手机震动一下

倒入框架 #import AudioServicesPlayAlertSound(kSystemSoundIDVibrate); 或者 AudioServicesPlaySystemSound(kSystemSoundIDVibrate);

120、layoutSubviews方法什么时候调用?

1、init方法不会调用

2、addSubview方法等时候会调用

3、bounds改变的时候调用

4、scrollView滚动的时候会调用scrollView的layoutSubviews方法(所以不建议在scrollView的layoutSubviews方法中做复杂逻辑)

5、旋转设备的时候调用

6、子视图被移除的时候调用

参考请看:http://blog.logichigh.com/2011/03/16/when-does-layoutsubviews-get-called/

121、让UILabel在指定的地方换行

// 换行符为\n,在需要换行的地方加上这个符号即可,如 
label.numberOfLines = 0;
label.text = @"此处\n换行";

122、摇一摇功能

1、打开摇一摇功能

[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;

2、让需要摇动的控制器成为第一响应者

[self becomeFirstResponder];

3、实现以下方法

// 开始摇动
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
// 取消摇动
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event
// 摇动结束
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event

123、获取图片大小

CGFloat imageWidth = image.size.width;
CGFloat imageHeight = imageWidth * image.scale;

124、获取view的坐标在整个window上的位置

// v上的(0, 0)点在toView上的位置
CGPoint point = [v convertPoint:CGPointMake(0, 0) toView:[UIApplication sharedApplication].windows.lastObject];
或者
CGPoint point = [v.superview convertPoint:v.frame.origin toView:[UIApplication sharedApplication].windows.lastObject];

125、提交App Store审核程序限制

您的应用程序的未压缩大小必须小于4GB。每个Mach-O可执行文件(例如appname.app/appname)不能超过这些限制:对于MinimumOSVersion小于7.0的应用程序:TEXT二进制文件中所有部分的总数最多为80 MB 。对于MinimumOSVersion7.x到8.x的应用程序:TEXT对于二进制文件中每个体系结构片段的每个片段,最大为60 MB 。对于MinimumOSVersion9.0或更高版本的应用程序:__TEXT二进制文件中所有部分的总数最多为500 MB 。参阅:iTunes Connect开发者指南

126、修改UISegmentedControl的字体大小

[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];

127、在非ViewController的地方弹出UIAlertController对话框

//  最好抽成一个分类
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];
//...
id rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;
if([rootViewController isKindOfClass:[UINavigationController class]])
{
    rootViewController = ((UINavigationController *)rootViewController).viewControllers.firstObject;
}
if([rootViewController isKindOfClass:[UITabBarController class]])
{
    rootViewController = ((UITabBarController *)rootViewController).selectedViewController;
}
[rootViewController presentViewController:alertController animated:YES completion:nil];

128、获取一个view所属的控制器

// view分类方法
- (UIViewController *)belongViewController {
    for (UIView *next = [self superview]; next; next = next.superview) {
        UIResponder* nextResponder = [next nextResponder];
        if ([nextResponder isKindOfClass:[UIViewController class]]) {
            return (UIViewController *)nextResponder;
        }
    }
    return nil;
}

129、UIImage和base64互转

// view分类方法
- (NSString *)encodeToBase64String:(UIImage *)image {
 return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}

- (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {
  NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];
  return [UIImage imageWithData:data];
}

130、UIWebView设置背景透明

[webView setBackgroundColor:[UIColor clearColor]];
[webView setOpaque:NO];

131、判断NSDate是不是今天

NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];
NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];
if([today day] == [otherDay day] &&
   [today month] == [otherDay month] &&
   [today year] == [otherDay year] &&
   [today era] == [otherDay era]) {
    // 是今天
}

132、设置tableView分割线颜色

[self.tableView setSeparatorColor:[UIColor myColor]];

133、设置屏幕方向

[[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeLeft) forKey:@"orientation"];

134、比较两个颜色是否相等

- (BOOL)isEqualToColor:(UIColor *)otherColor {
    CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();
6
    UIColor *(^convertColorToRGBSpace)(UIColor*) = ^(UIColor *color) {
        if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) == kCGColorSpaceModelMonochrome) {
            const CGFloat *oldComponents = CGColorGetComponents(color.CGColor);
            CGFloat components[4] = {oldComponents[0], oldComponents[0], oldComponents[0], oldComponents[1]};
            CGColorRef colorRef = CGColorCreate( colorSpaceRGB, components );
6
            UIColor *color = [UIColor colorWithCGColor:colorRef];
            CGColorRelease(colorRef);
            return color;            
        } else
            return color;
    };
6
    UIColor *selfColor = convertColorToRGBSpace(self);
    otherColor = convertColorToRGBSpace(otherColor);
    CGColorSpaceRelease(colorSpaceRGB);
    return [selfColor isEqual:otherColor];
}

135、tableViewCell分割线顶到头

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    [cell setSeparatorInset:UIEdgeInsetsZero];
    [cell setLayoutMargins:UIEdgeInsetsZero];
    cell.preservesSuperviewLayoutMargins = NO;
}

- (void)viewDidLayoutSubviews {
    [self.tableView setSeparatorInset:UIEdgeInsetsZero];
    [self.tableView setLayoutMargins:UIEdgeInsetsZero];
}

136、不让控制器的view随着控制器的xib拉伸或压缩

self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

137、cocoaPods报错 : [!] Unable to add a source with url https://github.com/CocoaPods/Specs.git named master-1.

You can try adding it manually in ~/.cocoapods/repos or via pod repo add.

解决方法:这是因为电脑里安装了另外一个Xcode导致cocoapods找不到路径了

在终端执行 sudo xcode-select -switch /Applications/Xcode.app 即可

138、安装cocoapods的时候出现 ERROR: While executing gem … (Errno::EPERM)

Operation not permitted - /usr/bin/pod

解决办法:直接在终端执行 sudo gem install -n /usr/local/bin cocoapods

139、在状态栏增加网络请求的菊花,类似safari加载网页的时候状态栏菊花

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

140、检查一个rect是否包含一个point

// point是否在rect内
BOOL isContains = CGRectContainsPoint(rect, point);

141、在指定的宽度下,让UILabel自动设置最佳font

label.adjustsFontSizeToFitWidth = YES;

142、将一个image保存在相册中

UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

或者

#import
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
        changeRequest.creationDate          = [NSDate date];
    } completionHandler:^(BOOL success, NSError *error) {
        if (success) {
            NSLog(@"successfully saved");
        }
        else {
            NSLog(@"error saving to photos: %@", error);
        }
    }];

143、修改cell.imageView的大小

UIImage *icon = [UIImage imageNamed:@""];
CGSize itemSize = CGSizeMake(30, 30);
UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);
CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);
[icon drawInRect:imageRect];
cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

144、为一个view添加虚线边框

 CAShapeLayer *border = [CAShapeLayer layer];
    border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;
    border.fillColor = nil;
    border.lineDashPattern = @[@4, @2];
    border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;
    border.frame = view.bounds;
    [view.layer addSublayer:border];

145、UITextView中打开或禁用复制,剪切,选择,全选等功能

// 继承UITextView重写这个方法
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
// 返回NO为禁用,YES为开启
    // 粘贴
    if (action == @selector(paste:)) return NO;
    // 剪切
    if (action == @selector(cut:)) return NO;
    // 复制
    if (action == @selector(copy:)) return NO;
    // 选择
    if (action == @selector(select:)) return NO;
    // 选中全部
    if (action == @selector(selectAll:)) return NO;
    // 删除
    if (action == @selector(delete:)) return NO;
    // 分享
    if (action == @selector(share)) return NO;
    return [super canPerformAction:action withSender:sender];

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