iOS-如何正确获取接触点？

当用户在视图上移动手指时，我需要获取每个接触点

这就是我在

CustomView.m

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesMoved:touches withEvent:event];

    UITouch *touch = [[touches allObjects] objectAtIndex:0];

    CGPoint touchLocation = [touch locationInView:self];

    NSLog(@"touch location is %f", touchLocation.x);
}

然后我检查日志，输出为：

2016-05-23 19:49:45.116 AutoLayoutTest[32321:3809723] touch location is 6.000000
2016-05-23 19:49:45.134 AutoLayoutTest[32321:3809723] touch location is 10.500000
2016-05-23 19:49:45.151 AutoLayoutTest[32321:3809723] touch location is 17.500000
2016-05-23 19:49:45.169 AutoLayoutTest[32321:3809723] touch location is 29.000000
2016-05-23 19:49:45.185 AutoLayoutTest[32321:3809723] touch location is 41.500000
2016-05-23 19:49:45.202 AutoLayoutTest[32321:3809723] touch location is 52.000000
2016-05-23 19:49:45.220 AutoLayoutTest[32321:3809723] touch location is 62.500000
2016-05-23 19:49:45.237 AutoLayoutTest[32321:3809723] touch location is 68.500000
2016-05-23 19:49:45.254 AutoLayoutTest[32321:3809723] touch location is 77.000000
2016-05-23 19:49:45.272 AutoLayoutTest[32321:3809723] touch location is 84.500000
2016-05-23 19:49:45.288 AutoLayoutTest[32321:3809723] touch location is 90.000000
2016-05-23 19:49:45.305 AutoLayoutTest[32321:3809723] touch location is 96.000000
2016-05-23 19:49:45.322 AutoLayoutTest[32321:3809723] touch location is 100.500000
2016-05-23 19:49:45.339 AutoLayoutTest[32321:3809723] touch location is 105.500000
2016-05-23 19:49:45.357 AutoLayoutTest[32321:3809723] touch location is 109.500000
2016-05-23 19:49:45.374 AutoLayoutTest[32321:3809723] touch location is 116.000000
2016-05-23 19:49:45.391 AutoLayoutTest[32321:3809723] touch location is 121.000000
2016-05-23 19:49:45.409 AutoLayoutTest[32321:3809723] touch location is 127.000000
2016-05-23 19:49:45.426 AutoLayoutTest[32321:3809723] touch location is 132.500000
2016-05-23 19:49:45.443 AutoLayoutTest[32321:3809723] touch location is 138.500000
2016-05-23 19:49:45.460 AutoLayoutTest[32321:3809723] touch location is 145.000000
2016-05-23 19:49:45.478 AutoLayoutTest[32321:3809723] touch location is 151.000000
2016-05-23 19:49:45.495 AutoLayoutTest[32321:3809723] touch location is 156.000000
2016-05-23 19:49:45.512 AutoLayoutTest[32321:3809723] touch location is 161.500000
2016-05-23 19:49:45.529 AutoLayoutTest[32321:3809723] touch location is 166.500000
2016-05-23 19:49:45.546 AutoLayoutTest[32321:3809723] touch location is 173.000000
2016-05-23 19:49:45.563 AutoLayoutTest[32321:3809723] touch location is 178.500000
2016-05-23 19:49:45.580 AutoLayoutTest[32321:3809723] touch location is 183.500000
2016-05-23 19:49:45.597 AutoLayoutTest[32321:3809723] touch location is 189.000000
2016-05-23 19:49:45.614 AutoLayoutTest[32321:3809723] touch location is 194.000000
2016-05-23 19:49:45.632 AutoLayoutTest[32321:3809723] touch location is 199.500000
2016-05-23 19:49:45.649 AutoLayoutTest[32321:3809723] touch location is 204.000000
2016-05-23 19:49:45.666 AutoLayoutTest[32321:3809723] touch location is 209.500000
2016-05-23 19:49:45.683 AutoLayoutTest[32321:3809723] touch location is 214.500000
2016-05-23 19:49:45.700 AutoLayoutTest[32321:3809723] touch location is 220.000000
2016-05-23 19:49:45.717 AutoLayoutTest[32321:3809723] touch location is 224.000000
2016-05-23 19:49:45.735 AutoLayoutTest[32321:3809723] touch location is 229.000000
2016-05-23 19:49:45.752 AutoLayoutTest[32321:3809723] touch location is 233.500000
2016-05-23 19:49:45.769 AutoLayoutTest[32321:3809723] touch location is 237.500000
2016-05-23 19:49:45.786 AutoLayoutTest[32321:3809723] touch location is 240.500000
2016-05-23 19:49:45.803 AutoLayoutTest[32321:3809723] touch location is 244.000000
2016-05-23 19:49:45.821 AutoLayoutTest[32321:3809723] touch location is 247.000000
2016-05-23 19:49:45.838 AutoLayoutTest[32321:3809723] touch location is 249.000000
2016-05-23 19:49:45.855 AutoLayoutTest[32321:3809723] touch location is 251.000000
2016-05-23 19:49:45.872 AutoLayoutTest[32321:3809723] touch location is 252.000000
2016-05-23 19:49:45.889 AutoLayoutTest[32321:3809723] touch location is 254.000000
2016-05-23 19:49:45.907 AutoLayoutTest[32321:3809723] touch location is 255.000000
2016-05-23 19:49:45.925 AutoLayoutTest[32321:3809723] touch location is 256.000000
2016-05-23 19:49:45.955 AutoLayoutTest[32321:3809723] touch location is 256.500000
2016-05-23 19:49:46.056 AutoLayoutTest[32321:3809723] touch location is 257.500000
2016-05-23 19:49:46.073 AutoLayoutTest[32321:3809723] touch location is 258.500000
2016-05-23 19:49:46.090 AutoLayoutTest[32321:3809723] touch location is 260.500000
2016-05-23 19:49:46.108 AutoLayoutTest[32321:3809723] touch location is 261.500000
2016-05-23 19:49:46.125 AutoLayoutTest[32321:3809723] touch location is 262.500000
2016-05-23 19:49:46.142 AutoLayoutTest[32321:3809723] touch location is 263.500000
2016-05-23 19:49:46.159 AutoLayoutTest[32321:3809723] touch location is 264.500000
2016-05-23 19:49:46.191 AutoLayoutTest[32321:3809723] touch location is 265.000000
2016-05-23 19:49:46.268 AutoLayoutTest[32321:3809723] touch location is 265.500000
2016-05-23 19:49:46.293 AutoLayoutTest[32321:3809723] touch location is 266.500000
2016-05-23 19:49:46.317 AutoLayoutTest[32321:3809723] touch location is 267.000000
2016-05-23 19:49:46.334 AutoLayoutTest[32321:3809723] touch location is 268.000000
2016-05-23 19:49:46.355 AutoLayoutTest[32321:3809723] touch location is 269.000000
2016-05-23 19:49:46.387 AutoLayoutTest[32321:3809723] touch location is 269.500000
2016-05-23 19:49:46.412 AutoLayoutTest[32321:3809723] touch location is 270.000000
2016-05-23 19:49:46.443 AutoLayoutTest[32321:3809723] touch location is 271.000000
2016-05-23 19:49:46.488 AutoLayoutTest[32321:3809723] touch location is 272.000000
2016-05-23 19:49:46.544 AutoLayoutTest[32321:3809723] touch location is 272.500000
2016-05-23 19:49:46.598 AutoLayoutTest[32321:3809723] touch location is 273.500000
2016-05-23 19:49:46.624 AutoLayoutTest[32321:3809723] touch location is 274.000000

请注意：打印值仅为X轴上的值。因为我只关心x轴的变化

问题是为什么有些点没有被检测到？我希望当用户在视图上拖动手指时，捕获的点应该是6、7、8、9、10、11，而不是6、10、17、29、41

我非常确定，当我在视图上拖动手指进行测试时，我是以正常速度进行的，而不是滑动。所以我不认为捕获的点应该是这样的

我还尝试从平移手势识别器中获取点。结果基本相同

---

我做错了吗？或者有没有更好的方法呢？

这是关于精度的问题。用户移动手指太快，无法获取每个像素的值，因此无法执行任何操作。

iPad屏幕的扫描频率为60 Hz。你得到的接触点坐标是在手指位置进行扫描时手指所在的位置。扫描本身是通过每行数字化仪栅极持续400µs的电脉冲完成的

对于较新的iPad，这个频率被提升到120赫兹（iPad Air 2和2 mini），iPad Pro甚至可以在240赫兹的频率下进行扫描。你们可以用这个函数得到这些中间点。以下是如何在objC中完成的：

- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    for (UITouch *touch in touches) {
        for (UITouch* coalescedTouch in [event coalescedTouchesForTouch:touch]) {
            CGPoint newPoint = [coalescedTouch locationInView:self];
        }
    }
}

---

如果手指移动足够快，即使如此，坐标中也会有间隙。插值以获取手指位于中间位置的时间-屏幕不会提供更高的精度。

如果我可以问一下，你想对收集的点做什么？@booleanBoy我正在尝试在用户移动手指时画一条线。当用户的手指通过该点时，我想改变该线某一点的颜色。当用户的手指沿着x轴移动时，你是否试图画一条直线？不是一条直线，而是当用户的手指通过某一点时，一条有彩色点的线。嗯。。如果是这样的话。忘记点的准确性。当用户的手指触摸一个看起来像点的视图时，我是否有可能检测到用户在该视图上的触摸？是的，您必须使用功能CGRECT INTERSECTSRECT来检测手指是否触摸该点视图