将点击事件添加到图像答案

【问题标题】：Adding click event to image将点击事件添加到图像
【发布时间】：2013-04-10 06:03:19
【问题描述】：

我是目标 c 的新手。我有一张图片，我想在点击它时显示一些警告消息像这样添加图像-

AHolder = [[UIImageView alloc] initWithFrame:CGRectMake(5, 80, 40, 40)];
    UIImage *imageA = [UIImage imageNamed:@"A.png"];
    AHolder.image = imageA;
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(aPressed:) name:@"aPressed" object:nil];
    [view addSubview:AHolder]

它的事件是这样的-

 -(IBAction)aPressed:(id)sender
{
    UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"hello" message:@"a pressed" delegate:self cancelButtonTitle:@"cancle" otherButtonTitles:@"ok",nil];
    [alert show];
    [alert release];
}

它没有给我任何错误，但当我点击图像时也没有任何反应。请建议我任何解决方案。

【问题讨论】：

标签： iphone ios objective-c cocoa-touch uiimageview

【解决方案1】：

向图像视图添加点击手势。

UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture)];
tapGesture.numberOfTapsRequired=1;
[AHolder setUserInteractionEnabled:YES];
[AHolder addGestureRecognizer:tapGesture];
[tapGesture release];

-(void)handleTapGesture{
//do what ever you want here
}

否则，只需使用带有背景图像的按钮。

【讨论】：

【解决方案2】：

使用 tapGestureRecognizer。因此，每当用户点击 iamgeview 时，您都可以做任何您想做的事情

UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(aPressed)];
tapGesture.numberOfTapsRequired=1;
[aHolder setUserInteractionEnabled:YES];
[aHolder addGestureRecognizer:tapGesture];

-(void)aPressed{
//do what ever you want here
}

【讨论】：

【解决方案3】：

对于您的问题，非常简单且最受欢迎的解决方案是在您的图像上使用自定义 UIButton。然后只需将选择器设置为您想要在单击按钮时调用的方法。确保 UIButton 和 UIImage 的框架相同。

【讨论】：

【解决方案4】：

在 xib 文件中添加“圆形矩形按钮”对象。将“Type”属性设置为“custom”，将“Background”属性设置为“nameofyourimage.extension”。

将 aPressed: 方法连接到圆形矩形按钮的 touch up inside 事件。

【讨论】：

【解决方案5】：

不需要将UIButton 放在您的图像上。只需使用UIButton 而不是UIImageView。您可以将UIButton backgroundimage 或image 属性设置为您想要的图像。

除此之外，您还可以像这样使用UITapGestureRecognizer：

将此代码发送至viewDidLoad

UITapGestureRecognizer *rec = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapRecognized:)];
[yourImage addGestureRecognizer:rec];
[yourImage setUserInteractionEnabled:YES]; //!! this is important

并实现这个委托方法

#define unused_related_to_gesture
- (void)tapRecognized:(UITapGestureRecognizer *)recognizer
{
    if(recognizer.state == UIGestureRecognizerStateBegan)
    {
        NSLog(@"\nUIGestureRecognizerStateBegan\n");
    }
    if(recognizer.state == UIGestureRecognizerStateCancelled)
    {
        NSLog(@"\nUIGestureRecognizerStateCancelled\n");
    }
    if(recognizer.state == UIGestureRecognizerStateChanged)
    {
        NSLog(@"\nUIGestureRecognizerStateChanged\n");
    }
    if(recognizer.state == UIGestureRecognizerStateEnded)
    {
        NSLog(@"\nUIGestureRecognizerStateEnded\n");
    }
    if(recognizer.state == UIGestureRecognizerStateFailed)
    {
        NSLog(@"\nUIGestureRecognizerStateFailed\n");
    }
    if(recognizer.state == UIGestureRecognizerStatePossible)
    {
        NSLog(@"\nUIGestureRecognizerStatePossible\n");
    }
    if(recognizer.state == UIGestureRecognizerStateRecognized)
    {
        NSLog(@"\nUIGestureRecognizerStateRecognized\n");
        // this section will contain your code of clicking the image.
        UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"hello" message:@"a pressed" delegate:self cancelButtonTitle:@"cancle" otherButtonTitles:@"ok",nil];
        [alert show];
        [alert release];
    }
}

【讨论】：