将触摸传输到 UIImageView 的副本

Question

我经历了漫长的旅程，试图将 UIImageViews 从 UITableView 拖放到另一个视图。

我让一切都按部就班。我对 UIPanGestureRecognizer 进行子类化，并将此自定义识别器附加到我加载到表视图中的所有 UIImageView。

然后，我重写识别器的 TouchMoved 方法，除其他外，将临时视图添加到应用程序键窗口上，然后将所选 UIImageView 的副本添加到该临时视图上，如下所示：

UIView *dragAndDropView = [[UIView alloc] initWithFrame: [[UIScreen mainScreen] applicationFrame]];
        dragAndDropView.backgroundColor = [UIColor whiteColor];

        [[UIApplication sharedApplication].keyWindow addSubview: dragAndDropView]; 

        ElementImageView * sourceImageView = (ElementImageView*)self.view;

        ElementImageView *newImageView =  [[ElementImageView alloc] initWithImage:sourceImageView.image];
        newImageView.userInteractionEnabled = YES;
        newImageView.frame = [self.view convertRect:sourceImageView.frame toView:dragAndDropView];

        [dragAndDropView addSubview:newImageView];

作为此代码的结果，我确实得到了我的dragAndDropView 顶部的源图像视图的副本（我可以看出，因为我将dragAndDropView 的背景颜色设置为白色）。如果我抬起手指并再次触摸复制的图像视图，我当然可以根据需要将其在屏幕上拖动。但我找不到一种方法将现有的触摸无缝转移到新对象。

有什么想法吗？

Answer 1

我认为您可以在 UIPanGestureRecognizer 处理程序上执行以下操作：

-(void) handlePan:(UIPanGestureRecognizer *)recognizer  {

if (recognizer.state == UIGestureRecognizerStateBegan) {

    // the initial position
    initialPanPositionX = self.transform.tx;
    initialPanPositionY = self.transform.ty;

    // create a copy of the imageview
    panImage = [[UIImageView alloc] initWithImage:imageView.image];
    panImage.frame = imageView.frame;

    [self.view addSubview:panImage];

}
else if (recognizer.state == UIGestureRecognizerStateChanged) {

    if (!startedMoving) {
        startedMoving = YES;

        [UIView beginAnimations:nil context:NULL]; {
            [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
            [UIView setAnimationDuration:0.2f];

            // an effect to increase a copy a little bit when start dragging
            CGAffineTransform zt = CGAffineTransformScale(CGAffineTransformIdentity, 1.2, 1.2);

            panImage.bounds = CGRectApplyAffineTransform(panImage.bounds, zt);

        }
        [UIView commitAnimations];

    }

    // translation
    CGPoint point = [recognizer translationInView:self];
    panImage.transform = CGAffineTransformMakeTranslation(initialPanPositionX + point.x, initialPanPositionY + point.y);


}
else if (recognizer.state == UIGestureRecognizerStateEnded ) {

    startedMoving = NO;

    // drop the imageView if it's inside the droppable view


    [panImage release], panImage = nil;

}

}

希望有帮助。