java - 使用 volatile 变量停止线程

Question

基本上，如果我删除不必要的东西，我就会得到以下代码:

public class Foo {
    private volatile boolean isFinished = false;
    private long timeOut = 60 * 1000;
    ...

    // Called asynchronously from another thread
    public setFinished(boolean value) {
        isFinished = value;
    }

    public wait() {
       ...
       long start = SystemClock.uptimeMillis();
       while(!isFinished && (SystemClock.uptimeMillis() - start) <= timeOut) {
           ...
       }

       if (isFinished) {
           // Log success!!!
           ...
       }
       else {
           // Log time out!!!
           ...
       }
    }
}

这段代码在 95% 的情况下都能工作。日志文件类似于:

`wait()` is called waiting starts
`setFinished(true)` is called
`setFinished(true)` returns
"success" entry in the log

但有时，根据日志文件会发生以下情况:

`wait()` is called waiting starts
`setFinished(true)` is called
`setFinished(true)` returns
about 60 seconds pass
"time out" entry in the log

有什么想法吗？

Answer 1

我唯一的猜测是这三个点内有一些东西阻止了循环执行:

while(!isFinished && (SystemClock.uptimeMillis() - start) <= timeOut) {
       ...
}

更新:您也可以尝试使用 System.currentTimeMillis()，因为 uptimeMillis() 时钟可能会因环境变化而停止。