如何停止setTimeout循环？ [英] How to stop a setTimeout loop?

问题描述

我正在尝试使用图像精灵构建一个加载指示器，我想出了这个功能

I'm trying to build a loading indicator with a image sprite and I came up with this function

function setBgPosition() {
   var c = 0;
    var numbers = [0, -120, -240, -360, -480, -600, -720];
    function run() {
       Ext.get('common-spinner').setStyle('background-position', numbers[c++] + 'px 0px');
        if (c<numbers.length)
        {
            setTimeout(run, 200);
        }else
        {
            setBgPosition();
        }
    }
    setTimeout(run, 200);
}

所以出来看起来像这样

http://jsfiddle.net/TTkre/

我不得不使用setBgPosition（）;在其他的内部保持这个循环运行，所以现在我的问题是如何停止这个循环一旦我想[加载完成]？

I had to use setBgPosition(); inside else to keep this running in a loop so now my problem is how to stop this loop once I want [load finished]?

推荐答案

p> setTimeout 返回一个定时器句柄，您可以使用它来停止超时， clearTimeout 。

setTimeout returns a timer handle, which you can use to stop the timeout with clearTimeout.

所以例如：

function setBgPosition() {
    var c = 0,
        timer = 0;
    var numbers = [0, -120, -240, -360, -480, -600, -720];
    function run() {
        Ext.get('common-spinner').setStyle('background-position', numbers[c++] + 'px 0px');
        if (c >= numbers.length) {
            c = 0;
        }
        timer = setTimeout(run, 200);
    }
    timer = setTimeout(run, 200);

    return stop;

    function stop() {
        if (timer) {
            clearTimeout(timer);
            timer = 0;
        }
}

所以你可以使用它作为：

So you'd use that as:

var stop = setBgPosition();
// ...later, when you're ready to stop...
stop();

请注意，不要将 setBgPosition 调用本身再次，我刚刚设置了 c 返回到 0 。否则，这不行。另请注意，我已经使用 0 作为超时未挂起的句柄值; 0 不是 setTimeout 中的有效返回值，所以它使一个方便的标志。

Note that rather than having setBgPosition call itself again, I've just had it set c back to 0. Otherwise, this wouldn't work. Also note that I've used 0 as a handle value for when the timeout isn't pending; 0 isn't a valid return value from setTimeout so it makes a handy flag.

这也是我认为你最好用 setInterval 而不是 setTimeout 。 setInterval 重复。所以：

This is also one of the (few) places I think you'd be better off with setInterval rather than setTimeout. setInterval repeats. So:

function setBgPosition() {
    var c = 0;
    var numbers = [0, -120, -240, -360, -480, -600, -720];
    function run() {
        Ext.get('common-spinner').setStyle('background-position', numbers[c++] + 'px 0px');
        if (c >= numbers.length) {
            c = 0;
        }
    }
    return setInterval(run, 200);
}

这样使用：

var timer = setBgPosition();
// ...later, when you're ready to stop...
clearInterval(timer);

尽管如此，我想找到一种方法来使 setBgPosition 通过检测到某些完成条件已经得到满足来阻止它们本身。

All of the above notwithstanding, I'd want to find a way to make setBgPosition stop things itself, by detecting that some completion condition has been satisfied.

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