未能在Android遊戲

Question

我想提出一個Android遊戲，應該顯示你已經失去了某一點的消息執行代碼。但是，由於某種原因，我無法弄清楚它的失敗。在checkLivesLeftValue（）上，如果用戶已經用完了他所得到的三個生命，它就調用onMethod（）。但是，當我創建敬酒時，應用程序失敗，爲什麼？

這是我的Java代碼：

import java.util.ArrayList; 

import android.app.AlertDialog; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.media.MediaPlayer; 
import android.os.Bundle; 
import android.os.Handler; 
import android.os.Message; 
import android.view.MotionEvent; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.widget.TextView; 
import android.widget.Toast; 

public class ExampleView extends SurfaceView implements SurfaceHolder.Callback 
{ 
class ExampleThread extends Thread 
{ 
    private ArrayList<Parachuter> parachuters; 
    private Bitmap parachuter; 
    private Paint black; 

    private boolean running; 

    private SurfaceHolder mSurfaceHolder; 
    private Context mContext; 
    private Handler mHandler; 
    private GameScreenActivity mActivity; 

    private long frameRate; 
    private boolean loading; 
    public float x; 
    public float y; 
    public MediaPlayer mp1; 
    public int parachuterIndexToResetAndDelete; 
    public int canvasGetWidth; 
    public int livesLeftValue; 

    public ExampleThread(SurfaceHolder sHolder, Context context, Handler handler) 
    { 
     mSurfaceHolder = sHolder; 
     mHandler = handler; 
     mContext = context; 
     mActivity = (GameScreenActivity) context; 

     parachuters = new ArrayList<Parachuter>(); 
     parachuter = BitmapFactory.decodeResource(getResources(), R.drawable.parachuteman); 
     black = new Paint(); 
     black.setStyle(Paint.Style.FILL); 
     black.setColor(Color.WHITE); 

     running = true; 

     // This equates to 26 frames per second. 
     frameRate = (long) (1000/26); 
     loading = true; 
    } 

    @Override 
    public void run() 
    { 
     while (running) 
     { 
      Canvas c = null; 
      try 
      { 
       c = mSurfaceHolder.lockCanvas(); 

       synchronized (mSurfaceHolder) 
       { 
        long start = System.currentTimeMillis(); 
        doDraw(c); 
        long diff = System.currentTimeMillis() - start; 

        if (diff < frameRate) 
         Thread.sleep(frameRate - diff); 
       } 
      } catch (InterruptedException e) 
      { 
      } 
      finally 
      { 
       if (c != null) 
       { 
        mSurfaceHolder.unlockCanvasAndPost(c); 
       } 
      } 
     } 
    } 

    protected void doDraw(Canvas canvas) 
    { 
     canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), black); 
     canvasGetWidth = canvas.getWidth(); 

     //Draw 
     for (int i = 0; i < parachuters.size(); i++) 
     { 
      canvas.drawBitmap(parachuter, parachuters.get(i).getX(), parachuters.get(i).getY(), null); 
      parachuters.get(i).tick(); 
     } 

     //Remove 
     for (int i = 0; i < parachuters.size(); i++) 
     { 
     if (parachuters.get(i).getY() > canvas.getHeight()) { 
      parachuters.remove(i); 
      onPlaySound(); 
      onMethod(); 
      checkLivesLeftValue(); 
     } 
    } 
    } 


    public void onPlaySound() 
    { 
     try { 
     mp1 = MediaPlayer.create(getContext(), R.raw.bombsound); 
     mp1.start(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
      mp1.release(); 
     } 
    } 

    public void onMethod() { 
     Toast.makeText(getContext(), "You lost!", 15).show(); 
    } 

    private void checkLivesLeftValue() { 
     // TODO Auto-generated method stub 
     if (livesLeftValue == 3) { 
      //Message to display: "You lost!" 
      onMethod(); 
     } 
     else { 
      livesLeftValue = livesLeftValue + 1; 
     } 
    } 

    public boolean onTouchEvent(MotionEvent event) 
    { 
     if (event.getAction() != MotionEvent.ACTION_DOWN) 
      return false; 
     float x1 = event.getX(); 
     float y1 = event.getY(); 

     initiateDrawParachuters(); 

     return true; 
    } 

    public void initiateDrawParachuters() 
    { 
     drawParachuter1(); 
    } 

    private void drawParachuter1() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 1 
     x = 68; 
     y = 40; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
     drawParachuter2(); 
    } 

    private void drawParachuter2() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 2 
     x = 100; 
     y = 80; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
     drawParachuter3(); 
    } 

    private void drawParachuter3() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 3 
     x = 150; 
     y = 120; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
     drawParachuter4(); 
    } 

    private void drawParachuter4() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 4 
     x = 170; 
     y = 150; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
     drawParachuter5(); 
    } 

    private void drawParachuter5() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 5 
     x = 180; 
     y = 170; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
     drawParachuter6(); 
    } 

    private void drawParachuter6() { 
     // TODO Auto-generated method stub 
     //Parachuter nr. 6 
     x = 200; 
     y = 180; 

     Parachuter p = new Parachuter(x, y); 
     parachuters.add(p); 
    } 

    public void drawParachuters() 
    { 
      Parachuter p = new Parachuter(x, y); 
      parachuters.add(p); 
      Toast.makeText(getContext(), "x=" + x + " y=" + y, 15).show(); 
    } 

    public void setRunning(boolean bRun) 
    { 
     running = bRun; 
    } 

    public boolean getRunning() 
    { 
     return running; 
    } 
} 

/** Handle to the application context, used to e.g. fetch Drawables. */ 
private Context mContext; 

/** Pointer to the text view to display "Paused.." etc. */ 
private TextView mStatusText; 

/** The thread that actually draws the animation */ 
private ExampleThread eThread; 

public ExampleView(Context context) 
{ 
    super(context); 

    // register our interest in hearing about changes to our surface 
    SurfaceHolder holder = getHolder(); 
    holder.addCallback(this); 

    // create thread only; it's started in surfaceCreated() 
    eThread = new ExampleThread(holder, context, new Handler() 
    { 
     @Override 
     public void handleMessage(Message m) 
     { 
      // mStatusText.setVisibility(m.getData().getInt("viz")); 
      // mStatusText.setText(m.getData().getString("text")); 
     } 
    }); 

    setFocusable(true); 
} 

@Override 
public boolean onTouchEvent(MotionEvent event) 
{ 
    return eThread.onTouchEvent(event); 
} 

public ExampleThread getThread() 
{ 
    return eThread; 
} 

@Override 
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) 
{ 
    // TODO Auto-generated method stub 
} 

public void surfaceCreated(SurfaceHolder holder) 
{ 
    if (eThread.getState() == Thread.State.TERMINATED) 
    { 
     eThread = new ExampleThread(getHolder(), getContext(), getHandler()); 
     eThread.start(); 
    } 
    else 
    { 
     eThread.start(); 
    } 
} 

@Override 
public void surfaceDestroyed(SurfaceHolder holder) 
{ 
    boolean retry = true; 
    eThread.setRunning(false); 

    while (retry) 
    { 
     try 
     { 
      eThread.join(); 
      retry = false; 
     } 
     catch (InterruptedException e) 
     { 
     } 
    } 
} 
} 

，這是我的logcat輸出：

03-24 16:32:59.442: W/dalvikvm(363): threadid=7: thread exiting with uncaught exception (group=0x4001d800) 
03-24 16:32:59.641: E/AndroidRuntime(363): FATAL EXCEPTION: Thread-8 
03-24 16:32:59.641: E/AndroidRuntime(363): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 
03-24 16:32:59.641: E/AndroidRuntime(363): at android.os.Handler.<init>(Handler.java:121) 
03-24 16:32:59.641: E/AndroidRuntime(363): at android.widget.Toast.<init>(Toast.java:68) 
03-24 16:32:59.641: E/AndroidRuntime(363): at android.widget.Toast.makeText(Toast.java:231) 
03-24 16:32:59.641: E/AndroidRuntime(363): at com.mysoftwaremobileapps.ParachuteHunter.ExampleView$ExampleThread.onMethod(ExampleView.java:135) 
03-24 16:32:59.641: E/AndroidRuntime(363): at com.mysoftwaremobileapps.ParachuteHunter.ExampleView$ExampleThread.doDraw(ExampleView.java:116) 
03-24 16:32:59.641: E/AndroidRuntime(363): at com.mysoftwaremobileapps.ParachuteHunter.ExampleView$ExampleThread.run(ExampleView.java:79) 
03-24 16:33:03.842: I/Process(363): Sending signal. PID: 363 SIG: 9 

Answer 1

您正在創建自Thread敬酒，這是不是有一個活套連接到它。最簡單的解決方案是從UI線程創建Toast，默認情況下是Looper。

而且，你已經有一個處理程序，這是一個視圖構造函數中創建的。您可以使用此處理程序將一些Runnable發佈到UI線程並在那裏創建Toast。

public void onMethod() { 
    mHandler.post(new Runnable() { 
     @Override 
     public void run() { 
      Toast.makeText(getContext(), "You lost!", 15).show(); 
     } 
    }); 
}