链接:http://www.jianshu.com/p/1ff9e44ccc78
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)
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
13、SDWebImage本地缓存策略需要注意。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。
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。
20、设置navigationBar上的title颜色和大小
[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]
31、自定义NSLog
#define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
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;}
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"; }}
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;}
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];}
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; } }}
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 { }}
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;}
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
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];}
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
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;}
98、UITableView (<UITableView: 0x7ff19b027000; >) failed to obtain a cell from its dataSource (<ViewController: 0x7ff19a507520>)
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]; }];
101、将tableView滚动到顶部
[tableView setContentOffset:CGPointZero animated:YES];或者[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];
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
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];}
112、scrollView滚动到最下边
CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height);[scrollView setContentOffset:bottomOffset animated:YES];
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;
119、让手机震动一下
倒入框架#import <AudioToolbox/AudioToolbox.h>AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);或者AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
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
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];
126、修改UISegmentedControl的字体大小
[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];
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;}
130、UIWebView设置背景透明
[webView setBackgroundColor:[UIColor clearColor]];[webView setOpaque:NO];
133、设置屏幕方向
NSNumber *orientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationLandscapeLeft];[[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];[UIViewController attemptRotationToDeviceOrientation];
134、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];}
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;
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 <Photos/Photos.h>[[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];}