本文主要记录日常工作中积累的一些iOS小技巧SDWebImage 加载大量高清图片时内存暴增解决方案：关闭SD加载高清大图时的解压缩static BOOL SDImageCacheOldShouldDecompressImages = YES; static BOOL SDImagedownloderOldShouldDecompressImages = YES; - (void)viewDidLoad { [super viewDidLoad]; // 关闭SD加载高清大图时的解压缩 SDImageCache *canche = [SDImageCache sharedImageCache]; SDImageCacheOldShouldDecompressImages = canche.shouldDecompressImages; canche.shouldDecompressImages = NO; SDWebImageDownloader *downloder = [SDWebImageDownloader sharedDownloader]; SDImagedownloderOldShouldDecompressImages = downloder.shouldDecompressImages; downloder.shouldDecompressImages = NO; } -(void)dealloc { SDImageCache *canche = [SDImageCache sharedImageCache]; canche.shouldDecompressImages = SDImageCacheOldShouldDecompressImages; SDWebImageDownloader *downloder = [SDWebImageDownloader sharedDownloader]; downloder.shouldDecompressImages = SDImagedownloderOldShouldDecompressImages; } 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。禁止手机睡眠[UIApplication sharedApplication].idleTimerDisabled = YES;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];禁用button高亮button.adjustsImageWhenHighlighted = NO;或者在创建的时候UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];动画切换window的根控制器[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{ BOOL oldState = [UIView areAnimationsEnabled]; [UIView setAnimationsEnabled:NO]; [UIApplication sharedApplication].keyWindow.rootViewController = [[RootViewController alloc]init]; [UIView setAnimationsEnabled:oldState]; } completion:^(BOOL finished) { }];去除数组中重复的对象NSArray *newArr = [oldArr valueForKeyPath:@"@distinctUnionOfObjects.self"];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 {}三个比较特殊的通知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）获取不到UICollectionView指定cell的问题[self.collectionView layoutIfNeeded];//添加这句话就好 QTMResContinueEditeCell *cell = (QTMResContinueEditeCell )[self.collectionView cellForItemAtIndexPath:[NSIndexPath indexPathForItem:_index inSection:0]];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]; }} 给一个view截图- (UIImage )cutImageWithView:(UIView )view{ UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 0); [view.layer renderInContext:UIGraphicsGetCurrentContext()]; UIImage image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return image;}注意对象为nil的时候，调用此对象分类的方法不会执行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;颜色转图片+ (UIImage )imageWithColor:(UIColor )color { //描述一个矩形 CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); //开启图形上下文 UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0); //获得图形上下文 CGContextRef ctx = UIGraphicsGetCurrentContext(); //使用color演示填充上下文 CGContextSetFillColorWithColor(ctx, [color CGColor]); //渲染上下文 CGContextFillRect(ctx, rect); UIImage image = UIGraphicsGetImageFromCurrentImageContext(); //关闭图形上下文 UIGraphicsEndImageContext(); return image; }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view某个角度设置圆角UIBezierPath maskPath = [UIBezierPath bezierPathWithRoundedRect:self.whiteView.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(10, 10)]; CAShapeLayer maskLayer = [[CAShapeLayer alloc] init]; maskLayer.frame = self.whiteView.bounds; maskLayer.path = maskPath.CGPath; self.whiteView.layer.mask = maskLayer; ##指定了需要成为圆角的角该参数是UIRectCorner类型的，可选的值有： UIRectCornerTopLeft UIRectCornerTopRight UIRectCornerBottomLeft UIRectCornerBottomRight UIRectCornerAllCorners 由角度转换弧度#define DegreesToRadian(x) (M_PI * (x) / 180.0)由弧度转换角度#define RadianToDegrees(radian) (radian180.0)/(M_PI)获取图片资源//建议使用前两种宏定义,性能高于后者#define LOADIMAGE(file,ext) [UIImage imageWithContentsOfFile:[[NSBundle mainBundle]pathForResource:file ofType:ext]]#define IMAGE(A) [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:A ofType:nil]]#define ImageNamed(_pointer) [UIImage imageNamed:[UIUtil imageName:_pointer]]#define UIImageName(name) [UIImage imageNamed:name]文件路径//获取temp#define PathTemp NSTemporaryDirectory()//获取Document#define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]//获取 Cache#define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]GCD代码只执行一次#define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);自定义NSLog//DEBUG 模式下打印日志,当前行#ifdef DEBUG# define DLog(fmt, …) NSLog((@"%s [Line %d] " fmt), PRETTY_FUNCTION, LINE, ##VA_ARGS);#else# define DLog(…)#endif//重写NSLog,Debug模式下打印日志和当前行数#if DEBUG#define NSLog(FORMAT, …) fprintf(stderr,"\nfunction:%s line:%d content:%s\n", FUNCTION, LINE, [[NSString stringWithFormat:FORMAT, ##VA_ARGS] UTF8String]);#else#define NSLog(FORMAT, …) nil#endif//DEBUG 模式下打印日志,当前行 并弹出一个警告#ifdef DEBUG# define ULog(fmt, …) { UIAlertView alert = [[UIAlertView alloc] initWithTitle:[NSString stringWithFormat:@"%s\n [Line %d] “, PRETTY_FUNCTION, LINE] message:[NSString stringWithFormat:fmt, ##VA_ARGS] delegate:nil cancelButtonTitle:@“Ok” otherButtonTitles:nil]; [alert show]; }#else# define ULog(…)#endifFont#define FONTS(size) [UIFont systemFontOfSize:(size)]#define BOLDFONTS(size) [UIFont boldSystemFontOfSize:(size)]GCD//主线程#define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);//异步线程#define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);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]Color// RGB颜色转换（16进制->10进制）#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]// 获取RGB颜色#define RGBA(r,g,b,a) [UIColor colorWithRed:r/255.0f green:g/255.0f blue:b/255.0f alpha:a]//清除背景色#define CLEARCOLOR [UIColor clearColor]// 随机色#define RandomCOLOR RGBCOLOR(arc4random_uniform(256),arc4random_uniform(256),arc4random_uniform(256))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;}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"];// 或者textField.attributedPlaceholder = [[NSAttributedString alloc] initWithString:placeholder attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:13],NSForegroundColorAttributeName : [UIColor grayColor]}];APP缓存/ * 存 数组数据/+(void)setObectOfArray:(NSArray *)array fileName:(NSString )fileName{ //缓存文件的 根路径 NSString path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]; // 缓存 文件夹 路径 NSString filePath = [path stringByAppendingPathComponent:@“XXX.dataCache”]; NSFileManager fileManager = [NSFileManager defaultManager]; if ([fileManager fileExistsAtPath:filePath] == NO) { [fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil]; } //缓存文件的路径 NSString * cacheFilePath = [filePath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.plist",fileName]]; BOOL isSuccess = [array writeToFile:cacheFilePath atomically:NO]; if (isSuccess) { NSLog(@“缓存数据成功:—%@",cacheFilePath); }else { NSLog(@“缓存数据失败:—%@",cacheFilePath); } }/ 取 数组数据/+(NSArray *)cacheArrayForFileName:(NSString *)fileName{ //缓存文件的 根路径 NSString path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]; // 缓存 文件夹 路径 NSString filePath = [path stringByAppendingPathComponent:@“XXX.dataCache”]; //缓存文件的路径 NSString * cacheFilePath = [filePath stringByAppendingPathComponent:[NSString stringWithFormat:@”%@.plist”,fileName]]; //取得缓存文件 NSArray array = [NSArray arrayWithContentsOfFile:cacheFilePath]; return array;}/ 清除 这个全部的缓存数据 */+(void)clearCacheListData:(void (^)())completion{ // 异线程 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ // 清楚缓存 //缓存文件的 根路径 NSString path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]; // 缓存 文件夹 路径 NSString filePath = [path stringByAppendingPathComponent:@“FortuneDonkey.dataCache”]; NSFileManager manager = [NSFileManager defaultManager]; //移除文件夹 [manager removeItemAtPath:filePath error:nil]; // 创建一个新的文件夹 [manager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil]; if (completion) { //回调主线程 dispatch_async(dispatch_get_main_queue(), ^{ completion(); }); } });}/ 清除SD缓存数据 */-(void)clearSDCacheData{ //先清除内存中的图片缓存 [[SDImageCache sharedImageCache] clearMemory]; //清除磁盘的缓存 [[SDImageCache sharedImageCache] clearDisk];}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;}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”); } }];系统相关的一些方法//获取系统版本#define IOS_VERSION [[[UIDevice currentDevice] systemVersion] floatValue]#define IS_IOS10_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 10.0)//获取当前语言#define CurrentLanguage ([[NSLocale preferredLanguages] objectAtIndex:0])//判断是否 Retina屏、设备是否%fhone 5、是否是iPad#define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)#define iPhone5 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 1136), [[UIScreen mainScreen] currentMode].size) : NO)#define iPhone6 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(750, 1334), [[UIScreen mainScreen] currentMode].size) : NO)#define isPad (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)//判断是真机还是模拟器#if TARGET_OS_IPHONE//iPhone Device#endif#if TARGET_IPHONE_SIMULATOR//iPhone Simulator#endif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 = @“我是文字”; }}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;}获取手机和 APP 信息 //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];NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];// 当前应用名称NSString *appCurName = [infoDictionary objectForKey:@“CFBundleDisplayName”];// 当前应用版本 NSString *appCurVersion = [infoDictionary objectForKey:@“CFBundleShortVersionString”];// 当前应用版本号码 int类型NSString *appCurVersionNum = [infoDictionary objectForKey:@“CFBundleVersion”]; UIImage绘制圆角- (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;}准确获取图片像素CGFloat fixelW = CGImageGetWidth(image.CGImage);CGFloat fixelH = CGImageGetHeight(image.CGImage);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;}获取当前控制器//获取当前屏幕显示的viewcontroller- (UIViewController *)getCurrentVC{ UIWindow *window = [[UIApplication sharedApplication].windows firstObject]; if (!window) { return nil; } UIView *tempView; for (UIView *subview in window.subviews) { if ([[subview.classForCoder description] isEqualToString:@“UILayoutContainerView”]) { tempView = subview; break; } } if (!tempView) { tempView = [window.subviews lastObject]; } id nextResponder = [tempView nextResponder]; while (![nextResponder isKindOfClass:[UIViewController class]] || [nextResponder isKindOfClass:[UINavigationController class]] || [nextResponder isKindOfClass:[UITabBarController class]]) { tempView = [tempView.subviews firstObject]; if (!tempView) { return nil; } nextResponder = [tempView nextResponder]; } return (UIViewController *)nextResponder;}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 { }}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”); } 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: { NSLog(@“当前设备无网络”); } break; case AFNetworkReachabilityStatusReachableViaWiFi: NSLog(@“当前wifi网络”); break; case AFNetworkReachabilityStatusReachableViaWWAN: NSLog(@“当前蜂窝移动网络”); break; default: break; } }]; [mgr startMonitoring];父视图透明不影响子视图的做法self.view.backgroundColor = [[UIColor whiteColor]colorWithAlphaComponent:0.7f];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;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);}两张图片合成+ (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;}制作水印// 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;}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];}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;}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; }}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;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;}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];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)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;}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)];}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];}UIView背景颜色渐变+ (CAGradientLayer *)setGradualChangingColor:(UIView *)view fromColor:(NSString *)fromHexColorStr toColor:(NSString *)toHexColorStr{ // CAGradientLayer类对其绘制渐变背景颜色、填充层的形状(包括圆角) CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = view.bounds; // 创建渐变色数组，需要转换为CGColor颜色 gradientLayer.colors = @[(__bridge id)[UIColor colorWithHexString:fromHexColorStr].CGColor,(__bridge id)[UIColor colorWithHexString:toHexColorStr].CGColor]; // 设置渐变颜色方向，左下点为(0,0), 右上点为(1,1) gradientLayer.startPoint = CGPointMake(0, 0.5); gradientLayer.endPoint = CGPointMake(1, 0.5); // 设置颜色变化点，取值范围 0.0~1.0 gradientLayer.locations = @[@0,@1]; return gradientLayer;}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;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];}UIWebView设置背景透明[webView setBackgroundColor:[UIColor clearColor]];[webView setOpaque:NO];设置tableView分割线颜色以及顶到头// 分割线颜色[self.tableView setSeparatorColor:[UIColor myColor]];// 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];}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];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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