如何删除UIImageView

Question

我正在做一个应用程序，用户添加和删除不同类型的UIImageview的对象显示像头发鼻子等我已经添加图像视图只有问题我面临的是如何删除这些图像我正在使用PanGestureRecognizer，我想知道在拖到顶部时删除Imageview在下面看到图像。

Answer 1

删除在这里是错误的词。

您可以从它的超级视图中删除它，这将破坏imageView如果其他对象没有其他对象强烈引用它。

[imageView removeFromSuperView]; 

或者你可以让它显示nil istead的图像，这将确保你的imageView仍然在这里，但它不显示任何东西。

imageView.image=nil; 

如果你想删除所显示的图像

说extraFeatures的NSMutableArray中，您可以：

[self.extraFeatures removeObject:imageView.image]; 

然后

[imageView removeFromSuperView]; 

**编辑：平移手势

- (void)pan:(UIPanGestureRecognizer *)sender 
{ 
    // move begins 
    if(sender.state == UIGestureRecognizerStateBegan) 
    { 
     // Do something when the move begin??? 
     // Maybe record the initial position 
    } 

    // Move the view around during the pan 
    else if (sender.state == UIGestureRecognizerStateChanged) 
    { 
     CGPoint move = [sender translationInView:self.view]; 
     sender.view.center = CGPointMake(sender.view.center.x + move.x, sender.view.center.y + move.y); 
     [sender setTranslation:CGPointZero inView:self.view]; 

     // test if we should remove the view, viewCenter outside of viewbounds 
     if(!CGRectContainsPoint(self.view.bounds, imageView.center)) 
     { 
      [sender.view removeFromSuperView]; 
     } 
    } 

    // End of move 
    else if (sender.state == UIGestureRecognizerStateEnded) 
    { 

     // test if we should remove the view, viewCenter outside of viewbounds 
     if(!CGRectContainsPoint(self.view.bounds, imageView.center)) 
     { 
      [sender.view removeFromSuperView]; 
     } 

     // else maybe comming back to the original position 
    } 
} 

Answer 2

只要做到这一点。

self.imageView.image = nil; 

Answer 3

- (void)pan:(UIPanGestureRecognizer *)sender 
{ 

typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) { 
    UIPanGestureRecognizerDirectionUndefined, 
    UIPanGestureRecognizerDirectionUp, 
    UIPanGestureRecognizerDirectionDown, 
    UIPanGestureRecognizerDirectionLeft, 
    UIPanGestureRecognizerDirectionRight 
}; 

static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined; 

switch (sender.state) { 

    case UIGestureRecognizerStateBegan: { 

     if (direction == UIPanGestureRecognizerDirectionUndefined) { 

      CGPoint velocity = [sender velocityInView:recognizer.view]; 

      BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x); 

      if (isVerticalGesture) { 
       if (velocity.y > 0) { 
        direction = UIPanGestureRecognizerDirectionDown; 
       } else { 
        direction = UIPanGestureRecognizerDirectionUp; 
       } 
      } 

      else { 
       if (velocity.x > 0) { 
        direction = UIPanGestureRecognizerDirectionRight; 
       } else { 
        direction = UIPanGestureRecognizerDirectionLeft; 
       } 
      } 
     } 

     break; 
    } 

    case UIGestureRecognizerStateChanged: { 
     switch (direction) { 
      case UIPanGestureRecognizerDirectionUp: { 
       [self handleUpwardsGesture:sender]; 
       break; 
      } 
      case UIPanGestureRecognizerDirectionDown: { 
       [self handleDownwardsGesture:sender]; 
       break; 
      } 
      case UIPanGestureRecognizerDirectionLeft: { 
       [self handleLeftGesture:sender]; 
       break; 
      } 
      case UIPanGestureRecognizerDirectionRight: { 
       [self handleRightGesture:sender]; 
       break; 
      } 
      default: { 
       break; 
      } 
     } 
    } 

    case UIGestureRecognizerStateEnded: { 
     direction = UIPanGestureRecognizerDirectionUndefined; 
     break; 
    } 

    default: 
     break; 
} 

} 

- (void)handleUpwardsGesture:(UIPanGestureRecognizer *)sender 
{ 
    NSLog(@"Up"); 
} 

- (void)handleDownwardsGesture:(UIPanGestureRecognizer *)sender 
{ 
    NSLog(@"Down"); 
} 

- (void)handleLeftGesture:(UIPanGestureRecognizer *)sender 
{ 
    NSLog(@"Left"); 
} 

- (void)handleRightGesture:(UIPanGestureRecognizer *)sender 
{ 
    NSLog(@"Right"); 
} 

让我知道它是否适合你与否。