iOS捕捉截屏事件并展示截图效果

摩拜单车、微信的截屏就做的比较人性化。

现在很多APP开始支持用户截屏后，主动获取截图并弹出分享视图，这样用户就不用去相册去找了，感觉体验不错，今天就分享一下 截屏开发的心得，希望能帮助iOS的朋友。

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
*/
}

以上就是截屏后的事例代码，最后附上效果图：

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