有很多方法可以做到这一点。Android 确实支持普通的 JavaThread
对象,您可以使用它们。您可以搜索(SO)android game loop
并可能找到很多示例。但是,如果您想尝试AsyncTask
,这里有一个示例实现:
public class PongView extends View {
public PongView(Context context) {
super(context);
}
public void setBallPosition(int x, int y) {
// relocate the ball graphic
}
}
然后,您的活动:
public class PongDriverActivity extends Activity implements OnSeekBarChangeListener {
private enum GameSpeed { SLOW, MEDIUM, FAST };
private PongView mGameView;
private PongDriverTask mWorker;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mGameView = new PongView(this);
mWorker = new PongDriverTask(GameSpeed.MEDIUM);
// if you need to pass some data to the worker:
mWorker.execute("one", "two", "three");
// else, declare the AsyncTask's first generic param as Void, and do:
//mWorker.execute();
setContentView(mGameView);
}
// you would connect this up to a button, to allow the user to stop
public void onStopClicked(View sender) {
if (mWorker.isRunning()) {
mWorker.stopRunning();
}
}
// you could connect this up to a slider, to allow the user to control the paddle
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
// you may need to convert progress to a y-coordinate
mWorker.setPaddlePosition(progress);
}
然后(可能在内部类 PongDriverActivity.java 中):
private class PongDriverTask extends AsyncTask<String, Integer, Integer> {
private int mDelay;
private boolean mRunning = true;
private int mPaddleY = 0;
public PongDriverTask(GameSpeed speed) {
if (speed == GameSpeed.SLOW) {
mDelay = 100;
} else if (speed == GameSpeed.MEDIUM) {
mDelay = 50;
} else if (speed == GameSpeed.FAST) {
mDelay = 10;
}
}
public synchronized boolean isRunning() {
return mRunning;
}
public synchronized void stopRunning() {
mRunning = false;
}
public synchronized void setPaddlePosition(int y) {
mPaddleY = 0;
}
private synchronized int getPaddlePosition() {
return mPaddleY;
}
@Override
protected void onPostExecute(Integer score) {
super.onPostExecute(score);
// here you could show a UI that shows the final score
}
@Override
protected void onPreExecute() {
super.onPreExecute();
mGameView.setBallPosition(0, 0);
// here you could throw up some UI that shows just
// before the game really starts
}
@Override
protected void onProgressUpdate(Integer... params) {
super.onProgressUpdate(params);
// retrieve updated game coordinates from params
mGameView.setBallPosition(params[0], params[1]); // x,y
}
@Override
protected Integer doInBackground(String... args) {
// If you have some information to pass to the background worker,
// it would be passed in args[0], args[1], etc.
// It doesn't have to be String data. you could change the generic
// to take something other than String as the first param, in which
// case, doInBackground() would take a variable length list of that
// other data type.
int ballX = 0;
int ballY = 0;
int score = 0;
while (isRunning()) {
// use your game engine to recalculate the ball position
// on this background thread
int paddleY = getPaddlePosition();
ballX += 1;
ballY += 2;
score++;
// now, update the UI, which must happen on the UI thread
publishProgress(ballX, ballY);
try {
Thread.sleep(mDelay);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return score;
}
}
任务的doInBackground()
方法将在后台线程上运行,因此您不能直接从那里修改 UI。但是,AsyncTask
我在上面覆盖的所有其他方法都是在 UI 线程上调用的,因此在其中任何一个中执行 UI 工作都是安全的。
此代码假定桨由搜索栏控制,您将Activity
为其设置更改侦听器。还有很多其他方法可以做到这一点。
我刚刚实现了一个粗略的游戏停止机制,你可以连接到一个按钮。如果您想允许用户暂停和恢复,您可以搜索暂停/恢复线程的实现,这也应该适用于此。例如:
如何在 Java 中从另一个线程暂停和恢复一个线程
更多阅读...
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