.......启动那些线程
while(true){
  if (都停止了){
   showMessage("");
   break;
}
}

解决方案 »

  1.   

    用join()方法。
    下面是示例:        class MyThread extends Thread
            {
                String name ;
                public MyThread(String str){
                    name = str;
                }
                public void run(){
                    int i  = 0;
                    try{
                        while (i < 100) {
                            sleep(100);
                            System.out.println(name + ":" + i);
                            i ++;
                        }
                    }
                    catch(InterruptedException e){
                        e.printStackTrace();
                    }
                }
            };
            Thread aa = new MyThread("aa");
            Thread bb = new MyThread("bb");
            Thread cc = new MyThread("cc");
            aa.start();
            bb.start();
            cc.start();
            try{
                aa.join();
            }
            catch(Exception e){
                e.printStackTrace();
            }
            try{
                bb.join();
            }
            catch(Exception e){
                e.printStackTrace();
            }
            try{
                cc.join();
            }
            catch(Exception e){
                e.printStackTrace();
            }
            System.out.println("Finished");