uiview - 使用 UIPanGestureRecognizer 仅在 UIImageview 框架中拖动 UILable

Question

UILable 拖入 UIView 框架不在 UIImageView 框架我正在使用以下代码为拖动标签使用 UIPanGestureRecognizer

 UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture1:)];
    [panGesture setMinimumNumberOfTouches:1];
    [self.imageView setBounds:CGRectMake(self.imageView.frame.origin.x,self.imageView.frame.origin.y ,self.imageView.frame.size.width, self.imageView.frame.size.height)];
    [panGesture setMaximumNumberOfTouches:1];
    panGesture.delegate=self;
    [title addGestureRecognizer:panGesture];
    panGesture = nil;

还有我的行动方法

-(void)handlePanGesture1:(UIPanGestureRecognizer *)sender
{

  CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.imageView];
  if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) 

{

     firstX = [[sender view] center].x;
     firstY = [[sender view] center].y;
}

 translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY+translatedPoint.y);

    [[sender view] setCenter:translatedPoint];
}

Answer 1

好吧，您应该使用以下内容限制您的 x,y:

    CGFloat maxPossibleX = CGRectGetMaxX(self.imageView.frame) - (CGRectGetWidth(sender.view.bounds)/2.0f);
    CGFloat maxPossibleY = CGRectGetMaxY(self.imageView.frame) - (CGRectGetHeight(sender.view.bounds) /2.0f);

    CGFloat minPossibleX = CGRectGetMinX(self.imageView.frame) + CGRectGetMidX(sender.view.bounds);
    CGFloat minPossibleY = CGRectGetMinY(self.imageView.frame) + CGRectGetMidY(sender.view.bounds);


    CGFloat actualX = translatedPoint.x;
    actualX= MAX(minPossibleX, actualX);
    actualX = MIN(maxPossibleX, actualX);

    CGFloat actualY = translatedPoint.y;
    actualY= MAX(minPossibleY, actualY);
    actualY = MIN(maxPossibleY, actualY);

    translatedPoint = CGPointMake(actualX, actualY);

我假设您的标签不是您的 imageView 的 subview 。如果您的标签是 imageView 的 subview :

    CGFloat maxPossibleX = CGRectGetMaxX(self.imageView.bounds) - (CGRectGetWidth(sender.view.bounds)/2.0f);
    CGFloat maxPossibleY = CGRectGetMaxY(self.imageView.bounds) - (CGRectGetHeight(sender.view.bounds) /2.0f);

    CGFloat minPossibleX = CGRectGetMidX(sender.view.bounds);
    CGFloat minPossibleY = CGRectGetMidY(sender.view.bounds);


    CGFloat actualX = translatedPoint.x;
    actualX= MAX(minPossibleX, actualX);
    actualX = MIN(maxPossibleX, actualX);

    CGFloat actualY = translatedPoint.y;
    actualY= MAX(minPossibleY, actualY);
    actualY = MIN(maxPossibleY, actualY);

    translatedPoint = CGPointMake(actualX, actualY);

编辑:我已经在一个测试项目中成功测试了这个方法:

-(void)handlePanGesture1:(UIPanGestureRecognizer *)sender
{

    CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.imageView];
    if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan)

    {

        firstX = [[sender view] center].x;
        firstY = [[sender view] center].y;
    }

    translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY+translatedPoint.y);

    CGFloat maxPossibleX = CGRectGetMaxX(self.imageView.bounds) - (CGRectGetWidth(sender.view.bounds)/2.0f);
    CGFloat maxPossibleY = CGRectGetMaxY(self.imageView.bounds) - (CGRectGetHeight(sender.view.bounds) /2.0f);

    CGFloat minPossibleX = CGRectGetMidX(sender.view.bounds);
    CGFloat minPossibleY = CGRectGetMidY(sender.view.bounds);


    CGFloat actualX = translatedPoint.x;
    actualX= MAX(minPossibleX, actualX);
    actualX = MIN(maxPossibleX, actualX);

    CGFloat actualY = translatedPoint.y;
    actualY= MAX(minPossibleY, actualY);
    actualY = MIN(maxPossibleY, actualY);

    translatedPoint = CGPointMake(actualX, actualY);
    [[sender view] setCenter:translatedPoint];
}