在Android中創建GameLoop

Question

我在此應用程序中創建與GameLoop相關的應用程序，如果用戶單擊屏幕上的圖像並在屏幕上以隨機速度在隨機方向上移動。該代碼有沒有錯誤，但是當我嘗試運行應用程序，我結束了一個強制關閉erroe ..

這是我的源代碼：

源代碼：GameLoop.java

public class GameLoop extends Activity { 
/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(new Sview(this)); 
} 
} 

源代碼爲：Sview.java

public class Sview extends SurfaceView implements Callback{ 

Bitmap bmp; 
public static float mHeight; 
public static float mWidth; 
ViewThread mThread; 
private ArrayList<elements> mElements=new ArrayList <elements>(); 
Paint p1; 

public Sview(Context context) { 
    super(context); 
    // TODO Auto-generated constructor stub 
    mThread = new ViewThread(); 
    getHolder().addCallback(this); 
} 

@Override 
public boolean onTouchEvent(MotionEvent event) 
{ 
    synchronized (mElements) { 
     mElements.add(new elements(getResources(), (int)event.getX(), (int)event.getY())); 
    } 
    return super.onTouchEvent(event); 
} 

public void update(long elapsed) 
{ 
    synchronized (mElements) 
    { 
     for(elements el : mElements) 
     { 
      el.animate_ele(elapsed); 
     } 
    } 
} 

public void mydraw(long elapsed, Canvas c) 
{ 
    c.drawColor(Color.BLACK); 
    synchronized (mElements) 
    { 
     for(elements el : mElements) 
     { 
      el.draw_ele(c); 
     } 
    } 
    c.drawText("FPS: "+Math.round(1000f/elapsed), 40, 40, p1); 
} 

public void surfaceChanged(SurfaceHolder holder, int format, int width, 
     int height) { 
    // TODO Auto-generated method stub 
    mHeight = height; 
    mWidth = width; 
} 

public void surfaceCreated(SurfaceHolder holder) { 
    // TODO Auto-generated method stub 
    if(!mThread.isAlive()) 
    { 
     mThread.setRun(true); 
     mThread.start(); 
    } 
} 

public void surfaceDestroyed(SurfaceHolder holder) { 
    // TODO Auto-generated method stub 
    if(mThread.isAlive()) 
    { 
     mThread.setRun(false); 
     mThread.stop(); 
    } 
} 
} 

源代碼：ViewThread.java

public class ViewThread extends Thread{ 

private Sview myView; 
private SurfaceHolder mHolder; 
private boolean mRun = false; 
private long StartTime, elapsed; 

public View Thread (Sview sv) 
{ 
    myView = sv; 
    mHolder = myView.getHolder(); 
    return sv; 
} 

public void setRun(boolean b) 
{ 
    mRun = b; 
} 

@Override 
public void run() 
{ 
    Canvas can = null; 
    StartTime = System.currentTimeMillis(); 
    while(mRun) 
    { 
     can = mHolder.lockCanvas(); 
     if(can!=null) 
     { 
      myView.update(elapsed); 
      myView.mydraw(elapsed, can); 
      elapsed = System.currentTimeMillis() - StartTime; 
      mHolder.unlockCanvasAndPost(can); 
     } 
     StartTime = System.currentTimeMillis(); 
    } 

} 
} 

源代碼：elements.java

public class elements { 

private int mx, my, mspeedx, mspeedy; 
Bitmap bmp1; 

public elements(Resources res, int x, int y) 
{ 
    bmp1 = BitmapFactory.decodeResource(res, R.drawable.ic_launcher); 
    mx = x; 
    my = y; 
    Random r1 = new Random(); 
    mspeedx = r1.nextInt(7)-3; 
    mspeedy = r1.nextInt(7)-3; 
} 

public void draw_ele(Canvas c) 
{ 
    c.drawBitmap(bmp1, mx, mx, null); 
} 

public void animate_ele(long elapsed) 
{ 
    mx+=mspeedx*(elapsed/50f); 
    my+=mspeedy*(elapsed/50f); 
    checkborder(); 
} 

private void checkborder() 
{ 
    if(mx<=0) 
    { 
     mspeedx=-mspeedx; 
     mx=0; 
    } 
    else if(mx>=Sview.mWidth) 
    { 
     mspeedx=-mspeedx; 
     mx=(int)Sview.mWidth; 
    } 
    if(my<=0) 
    { 
     mspeedy=-mspeedy; 
     my=0; 
    } 
    else if(my>=Sview.mHeight) 
    { 
     mspeedy=-mspeedy; 
     my=(int)Sview.mHeight; 
    } 
} 
} 

我得到的錯誤是：提前

08-29 00:05:55.982: E/AndroidRuntime(2295): FATAL EXCEPTION: Thread-8 
08-29 00:05:55.982: E/AndroidRuntime(2295): java.lang.NullPointerException 
08-29 00:05:55.982: E/AndroidRuntime(2295):  at com.pnf.game.ViewThread.run(ViewThread.java:31) 
08-29 00:05:56.292: E/global(2295): Deprecated Thread methods are not supported. 
08-29 00:05:56.292: E/global(2295): java.lang.UnsupportedOperationException 
08-29 00:05:56.292: E/global(2295):  at java.lang.VMThread.stop(VMThread.java:85) 
08-29 00:05:56.292: E/global(2295):  at java.lang.Thread.stop(Thread.java:1379) 
08-29 00:05:56.292: E/global(2295):  at java.lang.Thread.stop(Thread.java:1344) 
08-29 00:05:56.292: E/global(2295):  at com.pnf.game.Sview.surfaceDestroyed(Sview.java:85) 
08-29 00:05:56.292: E/global(2295):  at android.view.SurfaceView.reportSurfaceDestroyed(SurfaceView.java:568) 
08-29 00:05:56.292: E/global(2295):  at android.view.SurfaceView.updateWindow(SurfaceView.java:472) 
08-29 00:05:56.292: E/global(2295):  at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:206) 
08-29 00:05:56.292: E/global(2295):  at android.view.View.dispatchWindowVisibilityChanged(View.java:3891) 
08-29 00:05:56.292: E/global(2295):  at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719) 
08-29 00:05:56.292: E/global(2295):  at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719) 
08-29 00:05:56.292: E/global(2295):  at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719) 
08-29 00:05:56.292: E/global(2295):  at android.view.ViewRoot.performTraversals(ViewRoot.java:744) 
08-29 00:05:56.292: E/global(2295):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1727) 
08-29 00:05:56.292: E/global(2295):  at android.os.Handler.dispatchMessage(Handler.java:99) 
08-29 00:05:56.292: E/global(2295):  at android.os.Looper.loop(Looper.java:123) 
08-29 00:05:56.292: E/global(2295):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
08-29 00:05:56.292: E/global(2295):  at java.lang.reflect.Method.invokeNative(Native Method) 
08-29 00:05:56.292: E/global(2295):  at java.lang.reflect.Method.invoke(Method.java:521) 
08-29 00:05:56.292: E/global(2295):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
08-29 00:05:56.292: E/global(2295):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
08-29 00:05:56.292: E/global(2295):  at dalvik.system.NativeStart.main(Native Method) 

感謝。 。 。

Answer 1

java.lang.Thread的android java doc提到停止已棄用（請參閱​​（））。你真正需要做的是將ViewThread的mRun設置爲false，並在ViewThread上調用join以確保它停止運行。