Question

每次单击按钮

时都会调用此代码

   //Thread called when click a button
    Thread a = new Thread(new Runnable() {
        @Override
        public void run() {
            synchronized ((Object) contadordeMierda){
                Random rn = new Random();
                int n= rn.nextInt(10) + 1;
                contador++;

                try {
                    Thread.sleep(n*100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println(contador);
            }
   }
    });

    a.start();

当我快速触摸它几次时，我得到了这个外包：

I / System.out：1

I / System.out：2

I / System.out：5

I / System.out:9

...

如何等待一个线程完成另一个线程？所以印刷品去1 2 3 4 5 6 7 8 9 10 11 12 ......？

Answer 1

这是join() function的确切目的。很多次问过问题：How to wait for a number of threads to complete?。

Answer 2

为什么不这样做：只有当前没有线程运行时才启动新线程：

private boolean isThreadRunning = false;//declare a boolean field to store thread status whether it's running or not
...

if(!isThreadRunning){
    Thread a = new Thread(new Runnable() {
        @Override
        public void run() {
            synchronized ((Object) contadordeMierda){
                Random rn = new Random();
                int n= rn.nextInt(10) + 1;
                contador++;

                try {
                    Thread.sleep(n*100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println(contador);
                isThreadRunning = false;//Set the boolean variable to false because the thread has completed it's operations.
            }
   }
    });

    a.start();
    isThreadRunning = true;// Set the boolean to true because thread.start has been called.

}

如何等待线程在Android中启动另一个？

2 个答案: