Ios 发生触摸事件时UIImageView跳转

好的，基本上这段代码现在做的是根据用户拖动图像的位置沿Y轴上下拖动图像，然后图像返回到原始位置。我的问题是，如果有人不直接触摸UIImageView的中心并开始拖动，它会摇晃（非常不平滑）。当有人触摸UIImageView并开始拖动UIImageView时，UIImageView会稍微晃动，以直接移动到触摸事件的中心

我在考虑使用动画只是为了将其移动到图像需要移动的地方，还是有其他方法

如果这是一种低效的方式，我很抱歉。我对IOS的世界相当陌生

以下是我所拥有的：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    //Gets location of UIImageView.
    self.originalFrame = self.foregroundImage.frame;
}
//This method is used for moving the UIImageView along the y axis depending on touch events.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [[event allTouches] anyObject];
    if([touch view]==self.foregroundImage) {
        CGPoint location = [touch locationInView:self.view];
        location.x=self.foregroundImage.center.x;
        self.foregroundImage.center=location;
    }
}
//This method sets the UIImageView back to its original position.
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    CGRect newFrame = self.foregroundImage.frame;
    newFrame.origin.y = self.originalFrame.origin.y;
    [UIView animateWithDuration:1.1 animations:^{
        self.foregroundImage.frame = newFrame;
    }];
}

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您还需要保存ToucheSStart中相对于父视图的第一个位置。然后，您可以使用该值通过上一个位置和新位置之间的差异来更改帧。请参阅以下代码

- (void) touchesBegan: (NSSet*)   touches
            withEvent: (UIEvent*) event
{
  if (touches.count == 1)
  {
    UITouch* touch = [touches anyObject];
    self.touchLocation = [touch locationInView: self.view];
  }
}

- (void) touchesMoved: (NSSet*)   touches
            withEvent: (UIEvent*) event
{
  if (touches.count == 1)
  {
    UITouch* touch = [touches anyObject];
    CGPoint newTouchLocation = [touch locationInView: self.view];

    if (touch.view == self.foregroundImage)
    {
      /* Determine the difference between the last touch locations */
      CGFloat deltaX = newTouchLocation.x - self.touchLocation.x;
      CGFloat deltaY = newTouchLocation.y - self.touchLocation.y;

      /* Offset the foreground image */
      self.foregroundImage.center
        = CGPointMake(self.foregroundImage.center.x + deltaX,
                      self.foregroundImage.center.y + deltaY);
    }

    /* Keep track of the new touch location */
    self.touchLocation = newTouchLocation;
  }
}

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非常感谢你！我现在可以看到了。这正是我想要的。再次感谢你！