iphone - 来自 UITapGestureRecognizer 的 CGPoint

Question

我需要获取 UITapGestureRecognizer 的 x 和 y 位置，但在这样做时我的应用程序崩溃了

这是我创建识别器的代码

-(void)imagePickerController:(UIImagePickerController *) picker didFinishPickingMediaWithInfo:(NSDictionary *) info
{

    [[picker parentViewController] dismissModalViewControllerAnimated:YES];

    UIImage * image =[info objectForKey:@"UIImagePickerControllerOriginalImage"];

    [image drawInRect:CGRectMake(0,0, 200, 400)];

    MyImg =[[UIImageView alloc] initWithImage:image]; 

    UITapGestureRecognizer *recognizer;

    MyImg.userInteractionEnabled=YES;

    recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(getTouchColor:)];
    [MyImg addGestureRecognizer:recognizer];    
    [recognizer release];

    [self.view addSubview:MyImg];

    [picker release];

}

还有我的事件 GetTouchColor

-(void)getTouchColor:(UITapGestureRecognizer *) recognizer
{
    if (recognizer.state==UIGestureRecognizerStateEnded)
    {

    CGPoint point = [recognizer locationInView:MyImg];

        NSLog(@"%@", NSStringFromCGPoint(point));
}

如果我删除行

 CGPoint point = [recognizer locationInView:MyImg];

代码运行完美，应用程序不会崩溃。

我做错了什么？

谢谢

//对不起我的英语来自谷歌

Answer 1

检查 recognizer 不是 nil。向 nil 发送消息通常会返回 nil 或 0，这取决于返回类型，但是当它是一个结构返回类型时，结果是未定义的，并且可能(以及其他事情)导致崩溃。