子线程执行完毕之后在执行其他方法
//几个线程,写几个数
final CountDownLatch mCountDownLatch = new CountDownLatch(3);
new Thread(() -> {
System.out.println(“线程1”);
mCountDownLatch.countDown();
}).start();
new Thread(() -> {
System.out.println(“线程2”);
mCountDownLatch.countDown();
}).start();
new Thread(() -> {
System.out.println(“线程3”);
mCountDownLatch.countDown();
}).start();
//必须前面的线程执行完毕
System.out.println("最后执行的方法");