将图像从 UIPopoverController 拖放到 UIViewController

Question

我在 ViewController 中显示 UIPopoverController，并且我想将一张图像从弹出窗口拖到 ViewController。

我知道要做到这一点，我需要使用 UIGestureRecognizer，但我不知道如何做。我可以在弹出窗口周围移动图像，但无法将其拖放到 ViewController 中。

我的代码：

-(void)viewDidLoad
{
    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(moveImage:)];
    [panGesture setMinimumNumberOfTouches:1];
    [panGesture setMaximumNumberOfTouches:1];
    [self.view addGestureRecognizer:panGesture];    
}

- (void)moveImage:(UIPanGestureRecognizer *)recognizer 
{
    CGPoint newCenter = [recognizer translationInView:self.view];

    if([recognizer state] == UIGestureRecognizerStateBegan) {

        beginX = ball.center.x; 
        beginY = ball.center.y;
    }

    newCenter = CGPointMake(beginX + newCenter.x, beginY + newCenter.y);

    [ball setCenter:newCenter];
}