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我正在此应用程序中创建与 GameLoop 相关的应用程序，如果用户单击屏幕，则在屏幕上绘制图像并且它以随机速度和随机方向在屏幕上移动。在代码中没有错误但是当我尝试运行该应用程序时，我最终遇到了强制关闭错误。

这是我的源代码：

源代码：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));
}
}

源代码：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();
    }
}
}

源代码：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();
    }

}
}

源代码：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;
    }
}
}

我得到的错误是：

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)

提前致谢...

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1 回答 1

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java.lang.Thread 的 android java 文档提到 stop 已弃用（请参阅http://developer.android.com/reference/java/lang/Thread.html#stop () ）。您真正需要做的是将 ViewThread 的 mRun 设置为 false 并在 ViewThread 上调用 join 以确保它停止运行。

于 2012-09-07T01:36:18.843 回答