Question

所以我正在做自定义手势识别，我遇到了麻烦。我需要监控所有当前触摸，但touchesBegan，touchesEnded，touchesMoved和touchesCancelled都只能给我他们正在监控的触摸。我需要对所有触摸进行计算，无论它们是否受到监控。我做了一些研究，我已经看到了自己监控触摸的建议，但对我来说并不顺利。这是我的代码：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    /* Called when a touch begins */
    [myTouches unionSet:touches];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    NSArray *objects = [myTouches allObjects];

    for (UITouch *touch in touches) {
        for (UITouch *touch2 in objects) {
            if (CGPointEqualToPoint([touch2 locationInView:self.view], [touch previousLocationInView:self.view])) {
                [myTouches removeObject:touch2];
                [myTouches addObject:touch];
            }
        }
    }
}
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [myTouches minusSet:touches];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    [myTouches minusSet:touches];

    NSArray *objects = [myTouches allObjects];

    for (UITouch *touch in touches) {
        for (UITouch *touch2 in objects) {
            if (CGPointEqualToPoint([touch2 locationInView:self.view], [touch previousLocationInView:self.view])) {
                [myTouches removeObject:touch2];
            }
        }
    }
}

我想要的是：myTouches应该是屏幕上所有触摸的准确表示。我得到的是：myTouches不断增长，尽管有时从事件中触及的内容被正确注册为与myTouches中的触摸相同。我还做了一个测试，我在整数中计算了touchesBegan中注册的触摸次数，并减去了touchesEnded中注册的触摸，并且数字总是显示为正数，这意味着正在注册更多触摸比结束了。请帮忙！

Answer 1

尝试使用UIApplication的子类来监控应用程序中的所有触摸。

    @interface MyUIApplication : UIApplication

然后使用sendEvent

中的事件MyUIApplication

    - (void)sendEvent:(UIEvent *)event {

        [super sendEvent:event];
        NSSet *allTouches = [event allTouches];
        if ([allTouches count] > 0) {

             //To get phase of a touch
             UITouchPhase phase = ((UITouch *)[allTouches anyObject]).phase;
             if (phase == UITouchPhaseBegan){

                 //Do the stuff
             }
             //also you can use UITouchPhaseMoved, UITouchPhaseEnded,
             // UITouchPhaseCancelled and UITouchPhaseStationary
        }
    }

并且不要忘记在main

中添加该类

    int main(int argc, char *argv[])
    {
          @autoreleasepool {
                return UIApplicationMain(argc, argv, NSStringFromClass([MyUIApplication class]), NSStringFromClass([AppDelegate class]));
          }
    }

获取所有当前的UITouches，包括未更新的UITouches

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