iOS日常开发之常用代码

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、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) {
}];

7、去除数组中重复的对象

dataArray = [dataArray valueForKeyPath:@"@distinctUnionOfObjects.self"];

8、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

9、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）

10、上线前注意：

• 删掉代码中所有的测试代码
• 如果后台有审核模式，提醒后台开启此模式
• 主流程再跑一跑
• 全局搜索waring，检查所有标记waring的地方

11、跳进app权限设置

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

    UIApplication *application = [UIApplication sharedApplication];
    NSURL *URL = [NSURL URLWithString:UIApplicationOpenSettingsURLString];

    if ([application respondsToSelector:@selector(openURL:options:completionHandler:)]) {
       [application openURL:URL options:@{} completionHandler:nil];
 
    } else {
       
       [application openURL:URL];
    }
}

12、给一个view截图

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

13、动态修改tableView的tableHeaderView或者tableFooterView的高度

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 = newView。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。

14、注意对象为nil的时候，调用此对象分类的方法不会执行

15、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;

16、设置navigationBar上的title颜色和大小

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

17、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;

}

18、view设置圆角

define kViewBorderRadius(View, Radius, Width, Color)\

[View.layer setCornerRadius:(Radius)];\

[View.layer setMasksToBounds:YES];\

[View.layer setBorderWidth:(Width)];\

[View.layer setBorderColor:[Color CGColor]] // view圆角

19、强／弱引用

// weak
define kWeakSelf(type) __weak typeof(type) weak##type = type; 

// strong
define kStrongSelf(type) __strong typeof(type) type = weak##type; 

20、由角度转换弧度

define kDegreesToRadian(x) (M_PI * (x) / 180.0)

21、由弧度转换角度

define kRadianToDegrees(radian) (radian*180.0)/(M_PI)

22、获取图片资源

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

23、获取temp

define kPathTemp NSTemporaryDirectory()

24、获取沙盒 Document

define kPathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]

25、获取沙盒 Cache

define kPathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]

26、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;
}

27、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;
}

28、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"];

29、统一收起键盘

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

30、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;
}

31、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;
}

32、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];
}

33、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;
}

34、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);
}

35、设置启动页后，依然显示之前的

删除app，手机重启，重新安装

36、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;    
}

37、获取手机和app信息

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];

CFShow(infoDictionary);

// app名称
NSString *app_Name = [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]; 

//手机别名： 用户定义的名称 
NSString* userPhoneName = [[UIDevice currentDevice] name]; 

//设备名称 
NSString* deviceName = [[UIDevice currentDevice] systemName]; 

//手机系统版本 
NSString* phoneVersion = [[UIDevice currentDevice] systemVersion]; 

//手机型号 
NSString* phoneModel = [[UIDevice currentDevice] model]; 

//地方型号  （国际化区域名称） 
NSString* localPhoneModel = [[UIDevice currentDevice] localizedModel]; 

38、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));
}

39、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;
}

40、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];
}

41、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;
}

42、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];
}

43、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]；

44、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;

  }
}
}

45、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 == ReachableViaWWAN) {

    NSLog(@"当前蜂窝移动网络");
}

46、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];

47、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;

48、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;
}

49、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];

50、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;
}

51、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 LHBTextAlignmentTypeLeftTop: {

      rect.origin = bounds.origin;
  }
      break;
  case LHBTextAlignmentTypeRightTop: {
      rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, bounds.origin.y);
  }
      break;
  case LHBTextAlignmentTypeLeftBottom: {
  
      rect.origin = CGPointMake(bounds.origin.x, CGRectGetMaxY(bounds) - rect.size.height);
  }
      break;
  case LHBTextAlignmentTypeRightBottom: {

      rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, CGRectGetMaxY(bounds) - rect.size.height);
  }
      break;
  case LHBTextAlignmentTypeTopCenter: {

      rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - rect.origin.y);
  }
      break;
  case LHBTextAlignmentTypeBottomCenter: {

      rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - CGRectGetMaxY(bounds) - rect.size.height);
  }
      break;
  case LHBTextAlignmentTypeLeft: {

      rect.origin = CGPointMake(0, rect.origin.y);
  }
      break;

  case LHBTextAlignmentTypeRight: {

      rect.origin = CGPointMake(rect.origin.x, 0);
  }
      break;
  case LHBTextAlignmentTypeCenter: {

      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];
}

52、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;
}

53、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;
}
}

54、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;

55、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;
}

55、删除某个view所有的子视图

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

56、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]];

57、使用模拟器截图

快捷键command + s

或者File->Save Screen Shot

58、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

59、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app_name.app/app_name）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

60、UIImage和base64互转

- (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];
}

61、比较两个颜色是否相等

- (BOOL)isEqualToColor:(UIColor *)otherColor 
{

CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();

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 );

      UIColor *color = [UIColor colorWithCGColor:colorRef];

      CGColorRelease(colorRef);

      return color;           

  } else

      return color;
};

UIColor *selfColor = convertColorToRGBSpace(self);

otherColor = convertColorToRGBSpace(otherColor);

CGColorSpaceRelease(colorSpaceRGB);

return [selfColor isEqual:otherColor];
}

62、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;

63、检查一个rect是否包含一个point

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

64、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];

65、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];
}

本文地址：https://blog.csdn.net/lihao_ios/article/details/107670268