如何跟踪iPhone的多点触控事件？(how to track multitouch events

我希望跟踪从单独的触摸序列touchesBegan通过touchesMoved直到touchesEnded 。我得到单点触摸事件的坐标，但我想知道哪些触摸事件对应于触摸事件序列 。

举例来说，如果我移动整个屏幕上的第一个手指，然后触摸屏幕与第二根手指，并删除第一个手指 - 我想显示红色的第一根指头的坐标和第二手指在坐标蓝色。

这可能吗？如果是的话，我怎么确定哪些事件应该是“红”的事件应该是“蓝”？

这是我的代码：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self handleTouches:[event allTouches]];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [self handleTouches:[event allTouches]];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [self handleTouches:[event allTouches]];
}
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [self handleTouches:[event allTouches]];
}

- (BOOL)handleTouches: (NSSet*)touches {
    for (UITouch* touch in touches) {
        // ...
    }
}

Answer 1:

触摸对象是通过活动相一致，因此，如果你想跟踪一个红色和蓝色的接触，你会宣布为每个伊娃，当触摸开始，你指定你想要的是伊娃取其触摸，然后在你的循环，你会检查是否触摸是一样的，你存储指针。

UITouch *red;
UITouch *blue;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    for (UITouch* touch in touches) {
        if(something) red = touch;
        else blue = touch;
    }
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [self handleTouches:touches];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    for (UITouch* touch in touches) {
        if(red == touch) red = nil;
        if(blue == touch) blue = nil;
    }
}
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    for (UITouch* touch in touches) {
        if(red == touch) red = nil;
        if(blue == touch) blue = nil;
    }
}

- (BOOL)handleTouches: (NSSet*)touches {
    for (UITouch* touch in touches) {
        if(red == touch) //Do something
        if(blue == touch) //Do something else
    }
}