Фатальное исключение, inflateexception

Я пытаюсь сделать игру, похожую на понг. Я следил за учебником отсюда http://mikeyhogarth.wordpress.com/2010/10/09/how-to-develop-pong-for-android/, но в руководстве были фиксированные высота и ширина для отображения игры. Я пытался изменить код, чтобы найти фактические размеры экрана и использовать их вместо фиксированных настроек. Таким образом, игра будет масштабироваться независимо от размера экрана. В GameState.java я помещаю getWidth и GetHeight. Эти две строки были исходными строками размера экрана из GameState.

Оригинал

//screen width and height
    final int _screenWidth = 300;
    final int _screenHeight = 420;    

Изменено

//screen width and height
    final int _screenWidth = getWidth(null);
    final int _screenHeight = getHeight(null);

Основная деятельность

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

    @Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.dbryant423.classicpong.GameView
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</FrameLayout>

GameView.java

import android.content.Context;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class GameView extends SurfaceView  implements SurfaceHolder.Callback
{
private GameThread _thread;

public GameView(Context context, AttributeSet attrs) {
    super(context, attrs);

    //So we can listen for events...
    SurfaceHolder holder = getHolder();
    holder.addCallback(this);
    setFocusable(true); 

    //and instantiate the thread
    _thread = new GameThread(holder, context, new Handler());
}  

@Override
public boolean onKeyDown(int keyCode, KeyEvent msg) {
    return _thread.getGameState().keyPressed(keyCode, msg);
}

//Implemented as part of the SurfaceHolder.Callback interface
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    //Mandatory, just swallowing it for this example

}

//Implemented as part of the SurfaceHolder.Callback interface
@Override
public void surfaceCreated(SurfaceHolder holder) {
    _thread.start();
}

//Implemented as part of the SurfaceHolder.Callback interface
@SuppressWarnings("deprecation")
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    _thread.stop();
}

private float _x = 0;
private float _y = 0;

@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
_x = event.getX();
_y = event.getY();
}
if (event.getAction() == MotionEvent.ACTION_MOVE) {
final float xdiff = (_x - event.getX());
final float ydiff = (_y - event.getY());
_thread.getGameState().surfaceTouched(_x, _y);

_x = event.getX();
_y = event.getY();
}
return true;
}
}

GameThread.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Handler;
import android.view.SurfaceHolder;

public class GameThread extends Thread {

/** Handle to the surface manager object we interact with */
private SurfaceHolder _surfaceHolder;
private Paint _paint;
private GameState _state;

public GameThread(SurfaceHolder surfaceHolder, Context context, Handler handler)
{
_surfaceHolder = surfaceHolder;
_paint = new Paint();
_state = new GameState();
}

@Override
public void run() {
while(true)
{
Canvas canvas = _surfaceHolder.lockCanvas();
_state.update();
_state.draw(canvas,_paint);
_surfaceHolder.unlockCanvasAndPost(canvas);
}
}

public GameState getGameState()
{
return _state;
}
}

GameState.java

    import android.annotation.TargetApi;
    import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Paint;
    import android.graphics.Point;
    import android.graphics.Rect;
    import android.os.Build;
    import android.view.Display;
    import android.view.KeyEvent;
    import android.view.WindowManager;


    public class GameState {



 @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)  public static int
 getWidth(Context mContext){
        int width=0;
        WindowManager wm = (WindowManager)       mContext.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        if(Build.VERSION.SDK_INT>12){                   
            Point size = new Point();
            display.getSize(size);
            width = size.x;
        }
        else{
            width = display.getWidth();  // deprecated
        }
        return width;   }


    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)   public static int
 getHeight(Context mContext){
        int height=0;
        WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        if(Build.VERSION.SDK_INT>12){               
            Point size = new Point();
            display.getSize(size);
            height = size.y;
        }else{          
            height = display.getHeight();  // deprecated
        }
        return height;          }


    //screen width and height
    final int _screenWidth = getWidth(null);
    final int _screenHeight = getHeight(null);

    //The ball
    final int _ballSize = 10;
    int _ballX = 100;   int _ballY = 100;
    int _ballVelocityX = 3;     int _ballVelocityY = 3;

    //The bats
    final int _batLength = 75;  final int _batHeight = 10;
    int _topBatX = (_screenWidth/2) - (_batLength / 2);
    final int _topBatY = 20;
    int _bottomBatX = (_screenWidth/2) - (_batLength / 2);  
    final int _bottomBatY = 400;
    final int _batSpeed = 3;


    public GameState()
    {
    }

    //The update method
    public void update() {

    _ballX += _ballVelocityX;
    _ballY += _ballVelocityY;

    //DEATH!
    if(_ballY > _screenHeight || _ballY < 0)        
    {_ballX = 100;  _ballY = 100;}      //Collisions with the sides

    if(_ballX > _screenWidth || _ballX < 0)
                _ballVelocityX *= -1;   //Collisions with the bats      

    if(_ballX > _topBatX && _ballX < _topBatX+_batLength && _ballY < _topBatY)      
                     _ballVelocityY *= -1;  //Collisions with the bats      

    if(_ballX > _bottomBatX && _ballX < _bottomBatX+_batLength 
                    && _ballY > _bottomBatY)
                           _ballVelocityY *= -1;
    }

    public boolean keyPressed(int keyCode, KeyEvent msg)
    {
    if(keyCode == KeyEvent.KEYCODE_DPAD_LEFT) //left
    {
    _topBatX += _batSpeed; _bottomBatX -= _batSpeed;
    }

    if(keyCode == KeyEvent.KEYCODE_DPAD_RIGHT) //right
    {
    _topBatX -= _batSpeed; _bottomBatX += _batSpeed;
    }

    return true;
    }

    //the draw method
    public void draw(Canvas canvas, Paint paint) {

    //Clear the screen
    canvas.drawRGB(0, 0, 0);

    //set the colour
    paint.setARGB(255, 255, 255, 255);

    //draw the ball
    canvas.drawRect(new Rect(_ballX,_ballY,_ballX + _ballSize,_ballY + _ballSize),
                                 paint);

    //draw the bats
    canvas.drawRect(new Rect(_topBatX, _topBatY, _topBatX + _batLength,
                                          _topBatY + _batHeight), paint); //top bat
    canvas.drawRect(new Rect(_bottomBatX, _bottomBatY, _bottomBatX + _batLength, 
                                          _bottomBatY + _batHeight), paint); //bottom bat

    canvas.drawRect(new Rect(505, 500, 500, 0), paint); //Right Wall
    canvas.drawRect(new Rect(5, 500, 0, 0), paint); //Left Wall

    }


    public boolean surfaceTouched(float posX, float posY) {
    _topBatX = (int) posX;
    _bottomBatX = (int) posX;

    return true;
    }
    }

И, наконец, логарифм:

    12-01 14:32:43.861: D/AndroidRuntime(2318): Shutting down VM
12-01 14:32:43.861: W/dalvikvm(2318): threadid=1: thread exiting with uncaught exception (group=0x415c3b90)
12-01 14:32:43.871: E/AndroidRuntime(2318): FATAL EXCEPTION: main
12-01 14:32:43.871: E/AndroidRuntime(2318): Process: com.dbryant423.classicpong, PID: 2318
12-01 14:32:43.871: E/AndroidRuntime(2318): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dbryant423.classicpong/com.dbryant423.classicpong.MainActivity}: android.view.InflateException: Binary XML file line #5: Error inflating class com.dbryant423.classicpong.GameView
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread.access$700(ActivityThread.java:135)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.os.Handler.dispatchMessage(Handler.java:102)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.os.Looper.loop(Looper.java:137)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread.main(ActivityThread.java:4998)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at java.lang.reflect.Method.invokeNative(Native Method)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at java.lang.reflect.Method.invoke(Method.java:515)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at dalvik.system.NativeStart.main(Native Method)
12-01 14:32:43.871: E/AndroidRuntime(2318): Caused by: android.view.InflateException: Binary XML file line #5: Error inflating class com.dbryant423.classicpong.GameView
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.createView(LayoutInflater.java:620)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.Activity.setContentView(Activity.java:1928)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.dbryant423.classicpong.MainActivity.onCreate(MainActivity.java:12)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.Activity.performCreate(Activity.java:5243)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
12-01 14:32:43.871: E/AndroidRuntime(2318):     ... 11 more
12-01 14:32:43.871: E/AndroidRuntime(2318): Caused by: java.lang.reflect.InvocationTargetException
12-01 14:32:43.871: E/AndroidRuntime(2318):     at java.lang.reflect.Constructor.constructNative(Native Method)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at android.view.LayoutInflater.createView(LayoutInflater.java:594)
12-01 14:32:43.871: E/AndroidRuntime(2318):     ... 22 more
12-01 14:32:43.871: E/AndroidRuntime(2318): Caused by: java.lang.NullPointerException
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.dbryant423.classicpong.GameState.getWidth(GameState.java:20)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.dbryant423.classicpong.GameState.<init>(GameState.java:50)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.dbryant423.classicpong.GameThread.<init>(GameThread.java:20)
12-01 14:32:43.871: E/AndroidRuntime(2318):     at com.dbryant423.classicpong.GameView.<init>(GameView.java:24)
12-01 14:32:43.871: E/AndroidRuntime(2318):     ... 25 more
12-01 14:32:46.613: I/Process(2318): Sending signal. PID: 2318 SIG: 9