手势识别器

最新推荐文章于 2019-05-29 14:26:28 发布

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本文介绍如何在iOS应用中创建一个UIImageView对象，并添加手势识别功能，包括轻拍、长按、旋转、捏合和平移操作。通过实例代码演示手势的初始化、添加到视图以及实现相应动作的方法。

创建一个UIImageView类的对象

注意要把对象imageView的交互开了

// 创建一个imageView 添加手势用
    UIImage *image = [UIImage imageNamed:@"Selected"];
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    imageView.image = image;
    imageView.userInteractionEnabled = YES;
    [self.view addSubview:imageView];
    [imageView release];

创建好imageView后把创建的手势对象添加到imageView上去:

tap – 轻拍

手势类 UIGestureRecognizer
这个类是个抽象类其具体功能交给子类去实现
抽象类就是省代码的类

// 初始化一个轻拍手势的对象
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];

// 添加手势到视图上
    [imageView addGestureRecognizer:tap];

// 释放
    [tap release];

// 实现轻拍方法
- (void)tapAction:(UITapGestureRecognizer *)tap
{
       NSLog(@"你拍我了, 很轻");
       UIImageView *imageView = (UIImageView *)tap.view;
       imageView.image = [UIImage imageNamed:@"Highlighted"];

}

longPress – 长按

// 长按
// 添加手势步骤
// 1. 初始化手势 添加手势触发调用的方法
// 2. 把手势添加到视图上
// 3. 释放手势
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:)];
// 设置长按时间
    longPress.minimumPressDuration = 2.0;
    [imageView addGestureRecognizer:longPress];
    [longPress release];

// 实现长按手势
- (void)longPressAction:(UILongPressGestureRecognizer *)longPress
{
    // 判断一下状态 长按 只需要出发一次方法
    if (longPress.state == UIGestureRecognizerStateBegan) {
        NSLog(@"长按触发了多少次");
    }

}

rotation – 旋转

 UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationAciton:)];
    [imageView addGestureRecognizer:rotation];
    [rotation release];

// 实现旋转手势
- (void)rotationAciton:(UIRotationGestureRecognizer *)rotation
{
    NSLog(@"旋转...跳跃...");
// 形变属性 transform
// 参数一 要改变对应视图的形变属性
// 参数二 根据弧度去创建
    rotation.view.transform = CGAffineTransformRotate(rotation.view.transform, rotation.rotation);
// 每次转需要把旋转的角度 重置为0
// 因为要接替上一次的角度 开始旋转
    rotation.rotation = 0;
}

pinch – 捏合

UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAciton:)];
    [imageView addGestureRecognizer:pinch];
    [pinch release];

// 实现捏合收拾方法
- (void)pinchAciton:(UIPinchGestureRecognizer *)pinch
{
    NSLog(@"捏合");
// 相册的捏合 跟这个手势 没什么关系
// 根据缩放的刻度(比例)改变形变属性
    pinch.view.transform = CGAffineTransformScale(pinch.view.transform, pinch.scale, pinch.scale);
// 重置捏合的比例
    pinch.scale = 1;
}

pan – 平移

    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];
    [imageView addGestureRecognizer:pan];
    [pan release];

// 实现平移方法
- (void)panAction:(UIPanGestureRecognizer *)pan
{
    NSLog(@"平移");
// 获取平移的点(相对于要平移的视图)
    CGPoint p = [pan translationInView:pan.view];
    pan.view.transform = CGAffineTransformTranslate(pan.view.transform, p.x, p.y);
    [pan setTranslation:CGPointMake(0, 0) inView:pan.view];
}

swipe – 清扫

    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeAction:)];
    swipe.direction = UISwipeGestureRecognizerDirectionLeft;
    [imageView addGestureRecognizer:swipe];
    [swipe release];

// 实现轻扫方法
- (void)swipeAction:(UISwipeGestureRecognizer *)swipe
{
    NSLog(@"左扫");
}

screenEdgePan – 边缘扫

这个类继承于UIPanGestureRecognizer

 UIScreenEdgePanGestureRecognizer *screenEdgePan = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:@selector(screenEdgePanAction:)];
// 设置下从哪个边缘开始扫
    screenEdgePan.edges = UIRectEdgeRight;
    [imageView addGestureRecognizer:screenEdgePan];
    [screenEdgePan release];

// 实现边缘扫
- (void)screenEdgePanAction:(UIScreenEdgePanGestureRecognizer *)screenEdgePan
{
    NSLog(@"一定是 靠近屏幕边缘开始扫 才能触发");
}