本文主要是介绍iOS开发经验总结（三），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
101、将tableView滚动到顶部
| 1 2 3 | [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
| 1 | [youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents]; |
103、某个字体的高度
| 1 | font.lineHeight; |
104、删除某个view所有的子视图
| 1 2 | [[someView subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)]; |
105、删除NSUserDefaults所有记录
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 | //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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | - (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
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
| 1 2 3 | UIView *bgColorView = [[UIView alloc] init]; bgColorView.backgroundColor = [UIColor redColor]; [cell setSelectedBackgroundView:bgColorView]; |
109、UILabel设置内边距
| 1 2 3 4 5 6 | 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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | 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
| 1 2 | 快捷键command + s 或者File->Save Screen Shot |
112、scrollView滚动到最下边
| 1 2 | CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height); [scrollView setContentOffset:bottomOffset animated:YES]; |
113、UIView背景颜色渐变
| 1 2 3 4 5 6 | 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
| 1 | [yourView.layer removeAllAnimations] |
115、为UIView某个角添加圆角
| 1 2 3 4 5 6 | // 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
Xcode Derived data
117、将一个view放置在其兄弟视图的最上面
| 1 | [parentView bringSubviewToFront:yourView] |
118、将一个view放置在其兄弟视图的最下面
| 1 | [parentView sendSubviewToBack:yourView] |
119、让手机震动一下
| 1 2 3 4 5 | 倒入框架 #import AudioServicesPlayAlertSound(kSystemSoundID_Vibrate); 或者 AudioServicesPlaySystemSound(kSystemSoundID_Vibrate); |
120、layoutSubviews方法什么时候调用？
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1、init方法不会调用
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2、addSubview方法等时候会调用
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3、bounds改变的时候调用
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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)
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5、旋转设备的时候调用
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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
| 1 2 3 | // 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 2 3 4 5 6 7 8 9 10 11 12 | 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
| 1 2 | 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
| 1 2 3 4 | // 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
126、修改UISegmentedControl的字体大小
| 1 | [segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal]; |
127、在非ViewController的地方弹出UIAlertController对话框
| 1 2 3 4 5 6 7 8 9 10 11 12 13 | // 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
| 1 2 3 4 5 6 7 8 9 10 | // 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
| 1 2 3 4 5 6 7 8 9 | // 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
| 1 2 | [webView setBackgroundColor:[UIColor clearColor]]; [webView setOpaque:NO]; |
131、判断NSDate是不是今天
| 1 2 3 4 5 6 7 8 | 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
| 1 | [self.tableView setSeparatorColor:[UIColor myColor]]; |
133、设置屏幕方向
| 1 | [[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeLeft) forKey:@ "orientation" ]; |
134、比较两个颜色是否相等
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | - (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
| 1 2 3 4 5 6 7 8 9 10 | - (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
| 1 | 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)
| 1 | 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
| 1 | [UIApplication sharedApplication].networkActivityIndicatorVisible = YES; |
140、检查一个rect是否包含一个point
| 1 2 | // 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
| 1 | label.adjustsFontSizeToFitWidth = YES; |
142、将一个image保存在相册中
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 | 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
| 1 2 3 4 5 6 7 | 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
| 1 2 3 4 5 6 7 | 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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | // 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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