为什么张贴和放大器;取消了在不同bahviour一个查看和处理程序结果的可运行？ [英] Why is posting & cancelled a runnable on a View and Handler result in different bahviour?

问题描述

我已经打有关与的Runnable 和发现，如果你 postDelayed A 的Runnable 在查看然后去除回调将无法正常工作，但是如果你做同样的，但发布可运行在处理程序然后去除回调不工作。

为什么这项工作（的Runnable 的run（）code从不被执行）：

 可运行的可运行=新的Runnable（）{
    @覆盖
    公共无效的run（）{
        //执行一些code
    }
};处理程序处理程序=新的处理程序（）;
handler.postDelayed（可运行，10000）;
handler.removeCallbacks（可运行）;
 

在这里，因为这不（的Runnable 的run（）code总会被执行）：

 可运行的可运行=新的Runnable（）{
    @覆盖
    公共无效的run（）{
        //执行一些code
    }
};查看查看= findViewById（R.id.some_view）;
view.postDelayed（可运行，10000）;
view.removeCallbacks（可运行）;
 

解决方案

如果在查看不附加到一个窗口，我可以看到这种情况发生，什么看起来礼貌像Android的一个bug。战术上，因此，它可能是时间问题，确保你不张贴或删除的Runnable 后才查看附着到窗

如果你碰巧有一个示例项目躺在附近进行复制这个问题，我想看看它。否则，我会尽量做我自己，所以我可以有一些我可以用它来报告我的presumed错误。

---

更新

由于在评论中提到的， removeCallbacks（）上更多的普通部件的作品，所以才出现，这是一个的WebView 特异性问题，每OP的样本code。

I've been playing about with Runnables and have discovered that if you postDelayed a Runnable on a View then removing the callback won't work, however if you do the same but post the Runnable on a Handler then removing the callback does work.

Why does this work (Runnable run() code never gets executed):

Runnable runnable = new Runnable() {
    @Override
    public void run() {
        // execute some code
    }
};

Handler handler = new Handler();
handler.postDelayed(runnable, 10000);
handler.removeCallbacks(runnable);

where as this doesn't (Runnable run() code always gets executed)?:

Runnable runnable = new Runnable() {
    @Override
    public void run() {
        // execute some code
    }
};

View view = findViewById(R.id.some_view);
view.postDelayed(runnable, 10000);
view.removeCallbacks(runnable);

解决方案

If the View is not attached to a window, I can see this happening, courtesy of what looks like a bug in Android. Tactically, therefore, it may be a question of timing, making sure that you do not post or remove the Runnable until after the View is attached to the window.

If you happen to have a sample project lying around that replicates this problem, I'd like to take a look at it. Otherwise, I will try making my own, so I can have something I can use to report my presumed bug.

---

UPDATE

As mentioned in the comments, removeCallbacks() on more ordinary widgets works, so it appears this is a WebView-specific problem, per the OP's sample code.

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