如何使Java等待方法完成才能继续? [英] How do I make Java wait for a method to finish before continuing?

问题描述

所以我的问题是我需要这些方法一个接一个地运行，但是我无法弄清楚如何让这些方法在运行之前先等待. 任何帮助表示赞赏.谢谢你. 这是我的代码:

So my problem is that I need these methods to run one after another but I cannot work out how to make the methods wait before being run. Any help is appreciated. Thank you. Here is my code:

public void startMoving() throws InterruptedException
{
    moveEnemy("right",3);
    wait();
    moveEnemy("down",3);
    wait();
    moveEnemy("right",2);
    wait();
    moveEnemy("up",1);
    wait();
    moveEnemy("right",2);
    wait();
    moveEnemy("up",2);
    wait();
    moveEnemy("right",2);
    wait();
    moveEnemy("down",4);
    wait();
    moveEnemy("left",1);
    wait();
    moveEnemy("down",2);
    wait();
    moveEnemy("right",3);
    wait();
    moveEnemy("up",2);
    wait();
    moveEnemy("right",1);
    wait();
    moveEnemy("up",1);
    wait();
    moveEnemy("right",3);
}
public void moveEnemy(final String direction, final int numMoves)
{
    Thread moveThread = new Thread(new Runnable()
    {
        public void run()
        {
            isMoving = true;
            int originalX = getX();
            int originalY = getY();
            for(int loop = 0; loop <= 98*numMoves; loop++)
            {
                try 
                {
                    Thread.sleep(5);
                } 
                catch (InterruptedException e){}
                if(direction.equals("up"))
                {
                    setLocation(originalX,originalY+loop);
                }
                if(direction.equals("down"))
                {
                    setLocation(originalX,originalY-loop);
                }
                if(direction.equals("left"))
                {
                    setLocation(originalX-loop,originalY);
                }
                if(direction.equals("right"))
                {
                    setLocation(originalX+loop,originalY);
                }
            }
            try 
            {
                Thread.sleep(50);
            } 
            catch (InterruptedException e){}
            notify();
        }
    });
    moveThread.start();

推荐答案

最简单的解决方案可能是不使用线程，但我怀疑那是您想要的.

The easiest solution might be to not use threads, but i doubt that is what you want.

您可能正在寻找的是锁的概念:

What you might be looking for is the concept of locks:

方法可以通过调用以下内容来获取与对象关联的锁:

A method may acquire the lock associated with an object by calling:

synchronized(nameOfTheLockObject) {
    //do some code here
}

这将获取给定对象的锁，执行代码，然后释放该锁.如果该锁已被另一个方法/线程获取，则代码将暂停，直到另一个方法/线程释放该锁为止.

This acquires the lock of the given Object, executes the code and releases the lock afterwards. If the lock is already acquired by another method/thread, the code pauses until the lock is released by the other method/thread.

您还可以将同步语句添加到类的方法中，以使它们获取父对象的锁.

You can also add the synchronized statement to methods of a class to make them acquire the lock of the parent object.

有关此的更多信息，请参见: http://docs.oracle.com/javase/tutorial/essential/concurrency /locksync.html

More Information on this is given at: http://docs.oracle.com/javase/tutorial/essential/concurrency/locksync.html

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