pressGestureRecognizer和touchesBegan

Question

我有以下问题。我正在使用UILongPressGestureRecognizer将UIView设置为“切换模式”。如果UIView处于“切换模式”，则用户能够在屏幕上拖动UIView。为了在屏幕上拖动UIView，我使用了touchesBegan、touchesMoved和touchesEnded方法。

它可以工作，但是:我必须抬起手指才能拖动它，因为touchesBegan方法已经被调用，因此不会再次调用，因此我不能在屏幕上拖动UIView。

在UILongPressGestureRecognizer被触发后，有没有办法手动调用touchesBegan (UILongPressGestureRecognizer更改BOOL值，只有当BOOL值设置为YES时，touchesBegan才起作用)。

Answer 1

UILongPressGestureRecognizer是一个连续的手势识别器，所以不要求助于touchesMoved或UIPanGestureRecognizer，只需检查UIGestureRecognizerStateChanged，例如：

- (void)viewDidLoad
{
    [super viewDidLoad];

    UILongPressGestureRecognizer *gesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    [self.view addGestureRecognizer:gesture];
}

- (void)handleGesture:(UILongPressGestureRecognizer *)gesture
{
    CGPoint location = [gesture locationInView:gesture.view];

    if (gesture.state == UIGestureRecognizerStateBegan)
    {
        // user held down their finger on the screen

        // gesture started, entering the "toggle mode"
    }
    else if (gesture.state == UIGestureRecognizerStateChanged)
    {
        // user did not lift finger, but now proceeded to move finger

        // do here whatever you wanted to do in the touchesMoved
    }
    else if (gesture.state == UIGestureRecognizerStateEnded)
    {
        // user lifted their finger

        // all done, leaving the "toggle mode"
    }
}

Answer 2

我建议你使用UIPanGestureRecognizer，因为它是一种推荐的拖拽手势。

1. 您可以配置min。和最大。平移所需的触摸次数，使用以下属性：

maximumNumberOfTouches

minimumNumberOfTouches

• You可以处理像开始、改变和结束这样的状态，就像为所需的状态设置动画一样。

• 使用下面的方法将点转换成你想要的UIView。

- (void)setTranslation:(CGPoint)translation inView:(UIView *)view

示例：

1. You have to use a global variable to retain the old frame. Get this in UIGestureRecognizerStateBegan.
2. When the state is UIGestureRecognizerStateChanged. You can use the

-(void) pannningMyView:(UIPanGestureRecognizer*) panGesture{ if(panGesture.state==UIGestureRecognizerStateBegan){ //保留原始状态}else if(panGesture.state==UIGestureRecognizerStateChanged){ translatedPoint=panGesture translationInView:self.view；//在这里你可以设法获得新的拖动点。}}

1. 阻力的速度。基于速度，您可以提供动画来显示UIView的弹跳

- (CGPoint)velocityInView:(UIView *)view