iOS7之后，苹果开放出一个通知：UIApplicationUserDidTakeScreenshotNotification，截屏时系统就会发出这个通知，需要你注册这个通知，就能捕捉到截屏图片。

下面的代码，实现的是用户截屏后，捕获到截屏图片，展示出来：

//注册截屏通知

[[NSNotificationCenter defaultCenter] addObserver:self    selector:@selector(getScreenShot:)    name:UIApplicationUserDidTakeScreenshotNotification object:nil];

截屏后捕捉到事件：

- (void)getScreenshot:(NSNotification *)notification{ NSLog(@"捕捉截屏事件"); //获取截屏图片 UIImage *image = [UIImage imageWithData:[self imageDataScreenShot]]; //显示图片 UIImageView *imgV = [[UIImageView alloc]initWithImage:image]; imgV.frame = [UIScreen mainScreen].bounds; UIView *backView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)]; backView.backgroundColor = [[UIColor grayColor] colorWithAlphaComponent:0.8]; UIButton *shareBtn = [UIButton buttonWithType:UIButtonTypeSystem]; shareBtn.titleLabel.font = [UIFont systemFontOfSize:17.0]; [shareBtn setTintColor:[UIColor whiteColor]]; shareBtn.frame = CGRectMake(SCREEN_WIDTH/5,SCREEN_HEIGHT ,SCREEN_WIDTH*3/5,50); [shareBtn.layer setMasksToBounds:YES]; [shareBtn.layer setBorderWidth:1]; shareBtn.layer.cornerRadius = 6; [shareBtn setTitle:@"分享给好友" forState:UIControlStateNormal]; shareBtn.backgroundColor = [SouFunIMUtilityHelper colorWithHexString:@"#B22222"]; [shareBtn addTarget:self action:@selector(shareBtn:) forControlEvents:UIControlEventTouchUpInside]; [backView addSubview:imgV]; [backView addSubview:shareBtn]; UIWindow *window = [UIApplication sharedApplication].keyWindow; [window addSubview:backView]; [UIView animateWithDuration:1.0 animations:^{  imgV.transform = CGAffineTransformMakeScale(0.8, 0.8);  shareBtn.transform = CGAffineTransformMakeTranslation(0, -50); }]; //3秒后消失 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{  [backView removeFromSuperview]; });}

获取截屏图片data：

- (NSData *)imageDataScreenShot{ CGSize imageSize = CGSizeZero; imageSize = [UIScreen mainScreen].bounds.size; UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0); CGContextRef context = UIGraphicsGetCurrentContext(); for (UIWindow *window in [[UIApplication sharedApplication] windows]) {  CGContextSaveGState(context);  CGContextTranslateCTM(context, window.center.x, window.center.y);  CGContextConcatCTM(context, window.transform);  CGContextTranslateCTM(context, -window.bounds.size.width * window.layer.anchorPoint.x, -window.bounds.size.height * window.layer.anchorPoint.y);    if ([window respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])  {   [window drawViewHierarchyInRect:window.bounds afterScreenUpdates:YES];  }  else  {   [window.layer renderInContext:context];  }  CGContextRestoreGState(context); } UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return UIImagePNGRepresentation(image);}

按钮点击事件：

-(void)shareBtn:(UIButton *)sender{/* 分享代码*/}