UIScrollview 中的手势识别器

Question

我的视图中有一个滚动条，并且该滚动条内有几张图像。

我想将这些图像拖放到（和放入）我的滚动条中。我实现了 LongPressGestureRecognizer。

我还想知道（通过代码）哪个图像被长按。我想我使用 CGRectContainsPoint 修复了最后一个问题。但是我的代码没有对 CGRectContainsPoint 做出反应。它仍然记录“失败”。

- (void)viewDidLoad{

    //scroller properties
    scroller.contentSize = CGSizeMake(1300, 130);
    scroller.scrollEnabled = YES;
    scroller.directionalLockEnabled =YES;
    scroller.frame = CGRectMake(0, 874, 768, 130);

    UILongPressGestureRecognizer *longPress =
    [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];

    [image1 addGestureRecognizer:longPress];
    [image2 addGestureRecognizer:longPress];
    [image3 addGestureRecognizer:longPress];
    [longPress release];

}

-(void)longPressed:(UILongPressGestureRecognizer *)sender {


    CGPoint location = [sender locationInView:self.view];

    if(CGRectContainsPoint(image1.frame,  location)) {
        NSLog(@"image1 has been longpressed");
        // do something
    }

    if(CGRectContainsPoint(image2.frame,  location)) {
        NSLog(@"image2 has been longpressed");
        // do something
    }

    if(CGRectContainsPoint(image3.frame,  location)) {
        NSLog(@"image3 has been longpressed");
        // do something


    }

         else {
                 NSLog(@"fail");
}

有人有过这个 LongPressGestureRecognizer 的经验以及可以响应此功能的图像数量吗？

---

我确实成功地实现了两个手势识别器。所以我的滚动条中的图像现在可以拖动了。然而，它将自身限制在滚动视图内。我想要一些函数来负责将图像放在滚动视图前面，以便我可以将图像拖出滚动视图。

在我实现的 viewDidLoad 方法中

[scroller addSubview:image1];
[scroller addSubview:image2];
[scroller addSubview:image3];

[[self view] addSubview:scroller];

以及在我实现的 longPressed 方法中

[image1 bringSubviewToFront:self.view];

有人有好的提示吗？他们非常感激！

Answer 1

添加滚动视图并创建一个 IBOutlet

将三张图像添加到您的项目中，在此答案中我使用名称
image1.png、image2.png 和 image3.png

最后是代码

- (void) viewDidLoad{
        [super viewDidLoad];

        for (int i=1; i<=3; i++) {
            NSString *file = [NSString stringWithFormat:@"image%d.png", i];
            UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:file]];
            imageView.frame = CGRectMake(i * 200, 0, 200, 200);
            imageView.userInteractionEnabled = YES;
            imageView.tag = i;
                      
            UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer              alloc] initWithTarget:self action:@selector(longPress:)];
           
            [thumbView addGestureRecognizer:recognizer];
            [scrollView addSubview:thumbView];
        }
    }    

-(void)longPress: (UILongPressGestureRecognizer *)recognizer
{
        UIView *view  = recognizer.view;
        int index = view.tag;
        NSLog(@"image pressed : %i", índex);
}

通过这种方法，您将能够创建 3 个 imageView，并用更少的代码向它们添加一个手势识别器，并告诉您哪个 imageView 被长按了

但如果您想拖动 imageView UILongPressGestureRecognizer 不会为您工作，对于该任务，您应该使用 UIPanGestureRecognizer

如果您想将 imageView 拖出滚动视图，您可以模仿该效果
从scrollView中删除/隐藏imageView并添加具有相同图像的imageView
您隐藏/删除的 imageView 到底在哪里，您想要拖动 imageView 更像

是一种视觉效果，但有效

Answer 2

只需修改您的课程，如下所示：

 @implementation longGestureViewController

// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView 
{
    UIView *view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];

    self.view = view;
    self.view.tag = 100;
    [view release];

    mImageView1 = [[UIImageView alloc] initWithFrame:CGRectMake(10.0, 10.0, 100.0, 120.0)];
    mImageView1.image = [UIImage imageNamed:@"tile07.png"];
    [self.view addSubview:mImageView1];
    mImageView1.userInteractionEnabled = YES;
    mImageView1.tag = 1;
    [mImageView1 release];

    mImageView2 = [[UIImageView alloc] initWithFrame:CGRectMake(120.0, 10.0, 100.0, 120.0)];
    mImageView2.image = [UIImage imageNamed:@"tile08.png"];
    mImageView2.userInteractionEnabled = YES;
    mImageView2.tag = 2;
    [self.view addSubview:mImageView2];
    [mImageView2 release];

    mImageView3 = [[UIImageView alloc] initWithFrame:CGRectMake(10.0, 140.0, 100.0, 120.0)];
    mImageView3.image = [UIImage imageNamed:@"tile09.png"];
    mImageView3.tag = 3;
    mImageView3.userInteractionEnabled = YES;
    [self.view addSubview:mImageView3];
    [mImageView3 release];
}


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad 
{
    [super viewDidLoad];

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];

    [mImageView1 addGestureRecognizer:longPress];
    [longPress release];

    longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];

    [mImageView2 addGestureRecognizer:longPress];
    [longPress release];

    longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];

    [mImageView3 addGestureRecognizer:longPress];
    [longPress release];
}

-(void)longPressed:(UILongPressGestureRecognizer *)sender 
{
    CGPoint location = [sender locationInView:self.view];
    UIView *view = [self.view hitTest:location withEvent:UIEventTypeTouches];
    NSLog(@"%d", view.tag);
}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc 
{
    [super dealloc];
}