当我运行我的应用程序时，MenuView 显示正常，但是当我单击帮助图像所在的位置时，应用程序会强制关闭....
主要活动：
public class MainActivity extends Activity {
private static final String TAG = MainActivity.class.getSimpleName();
MenuView menuView;
HelpView helpView;
GameView gameView;
Handler myHandler = new Handler(){
public void handleMessage(Message msg) {
if(msg.what == 2){
if(menuView != null){
menuView = null;
}
MainActivity.this.setContentView(menuView);
new Thread(){
public void run(){
Looper.prepare();
gameView = new GameView(MainActivity.this);
Looper.loop();
}
}.start();
}
else if(msg.what == 3){
initHelpView();
}
}
};
public void initHelpView(){
helpView = new HelpView(this);
this.setContentView(helpView);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(new MenuView(this));
Log.d(TAG, "View added");
new Thread(){
public void run(){
Looper.prepare();
menuView = new MenuView(MainActivity.this);
}
}.start();
}
@Override
protected void onDestroy() {
Log.d(TAG, "Destroying...");
super.onDestroy();
}
@Override
protected void onStop() {
Log.d(TAG, "Stopping...");
super.onStop();
}
}
菜单视图：
public class MenuView extends SurfaceView implements
SurfaceHolder.Callback {
private static final String TAG = MenuView.class.getSimpleName();
private MenuViewThread thread;
private MainActivity activity;
public MenuView(Context context) {
super(context);
getHolder().addCallback(this);
thread = new MenuViewThread(getHolder(),this);
setFocusable(true);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
thread.setRunning(true);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
Log.d(TAG, "Surface is being destroyed");
boolean retry = true;
while (retry){
try {
thread.join();
retry = false;
}catch ( InterruptedException e){
//try again shutting down the thread
}
}
}
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.background), 0,0,null);
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.opensound), 105,240,null);
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.help), 225,240,null);
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.exit), 345,240,null);
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.startgame), 190,150,null);
}
public boolean onTouchEvent(MotionEvent event) {
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(event.getX()>225 && event.getX()<255 + 30
&& event.getY()>240& event.getY() <270 + 30){
activity.myHandler.sendEmptyMessage(3);
}else {
Log.d(TAG, "Coords: x=" + event.getX() + ",y=" + event.getY());
}
}return super.onTouchEvent(event);
}
}
菜单视图线程：
public class MenuViewThread extends Thread {
private static final String TAG = MenuViewThread.class.getSimpleName();
private MenuView menu;
private SurfaceHolder surfaceHolder;
private boolean running;
public void setRunning(boolean running){
this.running = running;
}
public MenuViewThread( SurfaceHolder surfaceHolder, MenuView menu){
super();
this.surfaceHolder = surfaceHolder;
this.menu = menu;
}
@Override
public void run() {
Canvas canvas;
while (running) {
canvas = null;
// try locking the canvas for exclusive pixel editing on the surface
try {
canvas = this.surfaceHolder.lockCanvas();
synchronized (surfaceHolder) {
// update game state
// draws the canvas on the panel
this.menu.onDraw(canvas);
}
} finally {
// in case of an exception the surface is not left in
// an inconsistent state
if (canvas != null) {
this.surfaceHolder.unlockCanvasAndPost(canvas);
}
} // end finally
}
}
}
这个应用程序看起来没有错误，但是当我点击图像时它出错了，有人有什么问题吗？
日志猫：
12-12 06:50:20.792: D/MainActivity(1342): View added
12-12 06:50:24.312: D/AndroidRuntime(1342): Shutting down VM
12-12 06:50:24.312: W/dalvikvm(1342): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
12-12 06:50:24.312: E/AndroidRuntime(1342): FATAL EXCEPTION: main
12-12 06:50:24.312: E/AndroidRuntime(1342): java.lang.NullPointerException
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.example.demo.MenuView.onTouchEvent(MenuView.java:75)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.view.View.dispatchTouchEvent(View.java:3766)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863)
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1671)
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1655)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.view.ViewRoot.handleMessage(ViewRoot.java:1785)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.os.Handler.dispatchMessage(Handler.java:99)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.os.Looper.loop(Looper.java:123)
12-12 06:50:24.312: E/AndroidRuntime(1342): at android.app.ActivityThread.main(ActivityThread.java:4627)
12-12 06:50:24.312: E/AndroidRuntime(1342): at java.lang.reflect.Method.invokeNative(Native Method)
12-12 06:50:24.312: E/AndroidRuntime(1342): at java.lang.reflect.Method.invoke(Method.java:521)
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-12 06:50:24.312: E/AndroidRuntime(1342): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-12 06:50:24.312: E/AndroidRuntime(1342): at dalvik.system.NativeStart.main(Native Method)
12-12 06:50:39.443: D/dalvikvm(1342): GC_FOR_MALLOC freed 6747 objects / 375136 bytes in 64ms
新的日志猫：
12-12 07:11:15.433: I/Process(1461): Sending signal. PID: 1461 SIG: 9
12-12 07:15:58.392: D/MainActivity(1491): View added
12-12 07:16:08.022: D/MenuView(1491): Surface is being destroyed
12-12 07:16:14.212: I/dalvikvm(1491): threadid=3: reacting to signal 3
12-12 07:16:14.222: I/dalvikvm(1491): Wrote stack traces to '/data/anr/traces.txt'
12-12 07:16:26.433: D/MainActivity(1501): View added
12-12 07:16:28.153: D/MenuView(1501): Coords: x=224.0,y=250.0
12-12 07:16:29.113: D/MenuView(1501): Surface is being destroyed
12-12 07:16:35.072: I/dalvikvm(1501): threadid=3: reacting to signal 3
12-12 07:16:35.072: I/dalvikvm(1501): Wrote stack traces to '/data/anr/traces.txt'
12-12 07:16:53.493: D/dalvikvm(1501): GC_FOR_MALLOC freed 7084 objects / 359392 bytes in 72ms