UITapGestureRecognizer无法在UIImageView中运行

Question

我有以下代码:

UITapGestureRecognizer *showStoryTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(showNewsStory:)];
[showStoryTapRecognizer setDelegate:self];
[self.storyImageView_ addGestureRecognizer:showStoryTapRecognizer];
[showStoryTapRecognizer release];

然而这并没有触发showNewsStory,为什么会这样呢？我在图像视图中启用了userInteraction.

Answer 1

您应该为UIImageView对象启用用户交互:

[self.storyImageView_ setUserInteractionEnabled:YES];

编辑:

尝试删除

[showStoryTapRecognizer setDelegate:self];

UITapGestureRecognizer据我所知,我认为它没有代表方法.

Answer 2

UITapGestureRecognizer *oneTouch=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(OneTouchHandeler)];

[oneTouch setNumberOfTouchesRequired:1];

[imageView addGestureRecognizer:oneTouch];

imageView.userInteractionEnabled = YES;

Answer 3

UIImageView是默认情况下禁用用户交互的UIView内部唯一子类UIKit.

Answer 4

我还注意到，在swift3中，如果要添加也要查找目标的手势识别器，而目标通常是self，则必须将要添加手势识别器的UIView设置为lazy var。否则，手势识别器将无法工作。我认为这是swift3中的错误。理想情况下，如果您在类完全初始化之前访问变量中的self，则它应该引发错误。以下代码无法检测到手势识别器。

let messageImageView: CachedImageView = {
    let iv = CachedImageView()
    iv.translatesAutoresizingMaskIntoConstraints = false
    iv.layer.cornerRadius = 16
    iv.layer.masksToBounds = true
    iv.contentMode = .scaleAspectFill
    iv.isUserInteractionEnabled = true
    let zoomTap = UITapGestureRecognizer(target: self, action: #selector(handleZoomTap))
    zoomTap.numberOfTapsRequired = 1
    iv.addGestureRecognizer(zoomTap)
    return iv
}()

要解决此问题，您必须使用 lazy var

lazy var messageImageView: CachedImageView = {
    let iv = CachedImageView()
    iv.translatesAutoresizingMaskIntoConstraints = false
    iv.layer.cornerRadius = 16
    iv.layer.masksToBounds = true
    iv.contentMode = .scaleAspectFill
    iv.isUserInteractionEnabled = true
    let zoomTap = UITapGestureRecognizer(target: self, action: #selector(handleZoomTap))
    zoomTap.numberOfTapsRequired = 1
    iv.addGestureRecognizer(zoomTap)
    return iv
}()