如何在Android游戏中重新启动Java线程?
我正在用Android创建一个演示游戏,用于学习。在游戏中,当两个物体之间发生碰撞时,我想显示一个“游戏结束”对话框。对话框中有一个“再次播放”按钮。按下时,螺纹应再次开始
我收到以下错误java.lang.IllegalThreadStateException: Thread already started
这是我的密码:
public class GamePanel extends SurfaceView implements Runnable {
private Thread thread = null;
private Ball ball;
private SurfaceHolder surfaceHolder;
private Paint paint;
private Canvas canvas;
volatile boolean playing = true;
private int hurdleCount = 3;
private Hurdles[] hurdles;
private int screenX, screenY;
private Rect ball_detectCollision;
public GamePanel(Context context, final int screenX, final int screenY) {
super(context);
ball = new Ball(context, screenX, screenY);
surfaceHolder = getHolder();
this.screenX = screenX;
this.screenY = screenY;
paint = new Paint();
canvas = new Canvas();
hurdles = new Hurdles[hurdleCount];
for (int i = 0; i < hurdleCount; i++) {
hurdles[i] = new Hurdles(context, screenX, screenY);
}
ball_detectCollision = new Rect(ball.getBall_x(), ball.getBall_y(), ball.getBitmap().getWidth(), ball.getBitmap().getHeight());
surfaceHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) {
System.out.println("Surface Created");
setUpdated_x(ball.getBall_x());
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
System.out.println("Surface Changed");
thread = new Thread(GamePanel.this);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
System.out.println("Surface Destroyed");
}
});
}
public int getUpdated_x() {
return updated_x;
}
public void setUpdated_x(int updated_x) {
this.updated_x = updated_x;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
setUpdated_x((int) event.getX());
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_UP:
break;
case MotionEvent.ACTION_DOWN:
initial_X = getUpdated_x();
break;
case MotionEvent.ACTION_MOVE:
if (getUpdated_x() < screenX - ball.getBitmap().getWidth() || getUpdated_x() > screenX - ball.getBitmap().getWidth()) {
draw(getUpdated_x());
}
break;
}
return true;
}
private void draw(int updatedValue) {
canvas = surfaceHolder.lockCanvas();
canvas.drawColor(Color.RED);
canvas.drawBitmap(ball.getBitmap(), updatedValue, ball.getBall_y(), paint);
ball.setBall_x(updatedValue);
ball_detectCollision.left = ball.getBall_x();
ball_detectCollision.top = screenY - ball.getBitmap().getHeight() - 260;
ball_detectCollision.right = ball.getBall_x() + ball.getBitmap().getWidth();
ball_detectCollision.bottom = screenY - ball.getBitmap().getHeight() - 260 + ball.getBitmap().getHeight();
for (int i = 0; i < hurdleCount; i++) {
canvas.drawBitmap(hurdles[i].getBitmap(), hurdles[i].getX(), hurdles[i].getY(), paint);
}
surfaceHolder.unlockCanvasAndPost(canvas);
}
@Override
public void run() {
while (playing) {
update();
draw(getUpdated_x());
control();
}
}
private void update() {
for (int i = 0; i < hurdleCount; i++) {
hurdles[i].update();
if (Rect.intersects(getBall_detectCollision(), hurdles[i].getDetectCollision())) {
System.out.println("Collision Detected");
playing = false;
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
@Override
public void run() {
showGameOverMessage();
}
});
}
}
}
public void pause() {
playing = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void showGameOverMessage() {
Toast.makeText(getContext(), "Game Over", Toast.LENGTH_SHORT).show();
Dialog showDialog = new Dialog(getContext());
showDialog.setContentView(R.layout.dialog_game_over);
Button playAgainButton = (Button) showDialog.findViewById(R.id.playAgainButton);
playAgainButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
playing = true;
thread.start();
}
});
showDialog.show();
}
}
# 1 楼答案
当游戏结束时,只需停止线程并再次播放按钮即可启动新线程
如果需要保存上一个线程的任何实例,请将它们保存在外部变量中。无论如何,在这种情况下有很多选择
编辑
你完全停止了你的线程。当你想开始新游戏时,你只需要开始一个新的线程
我建议保留这样的函数并删除
implements Runnable
# 2 楼答案
无法重新启动已停止的线程。解决方案是简单地实例化一个新的并启动它