onKeyDown не показывает диалог

В моем приложении я попытался переопределить метод onKeyDown и вызвал пользовательский диалог, но при запуске на устройстве этот пользовательский диалог не отображается. Я использовал отладчик и увидел, что метод onKeyDown вызывается, но диалоговое окно не появляется, и приложение завершает работу.

Это мой onKeyDown метод,

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    if ((keyCode == KeyEvent.KEYCODE_BACK))
    {
        LayoutInflater factory = LayoutInflater.from(FirstScreenActivity.this);

        View DialogView = factory.inflate(R.layout.exit_dialog, null);

        final Dialog exit_dialog = new Dialog(FirstScreenActivity.this,R.style.Theme_Dialog);
        exit_dialog.setContentView(DialogView);
        exit_dialog.show();
        Button btnYes = (Button) exit_dialog.findViewById(R.id.btnYes);
        btnYes.setOnClickListener(new View.OnClickListener() 
        {

            @Override
            public void onClick(View v) 
            {
                android.os.Process.killProcess(android.os.Process.myPid());
            }
        });
        Button btnNo = (Button) exit_dialog.findViewById(R.id.btnNo);
        btnNo.setOnClickListener(new View.OnClickListener() 
        {

            @Override
            public void onClick(View v) 
            {
                exit_dialog.dismiss();
            }
        });
    }
    return super.onKeyDown(keyCode, event);
}

А также получить эту ошибку в LogCat,

02-22 17:40:30.653: E/WindowManager(18524): Activity com.example.FirstScreenActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@417e7348 that was originally added here
02-22 17:40:30.653: E/WindowManager(18524): android.view.WindowLeaked: Activity com.example.FirstScreenActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@417e7348 that was originally added here
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.ViewRootImpl.<init>(ViewRootImpl.java:415)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:322)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:234)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:153)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.Window$LocalWindowManager.addView(Window.java:557)
02-22 17:40:30.653: E/WindowManager(18524):     at android.app.Dialog.show(Dialog.java:277)
02-22 17:40:30.653: E/WindowManager(18524):     at com.example.onKeyDown(FirstScreenActivity.java:173)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.KeyEvent.dispatch(KeyEvent.java:2715)
02-22 17:40:30.653: E/WindowManager(18524):     at android.app.Activity.dispatchKeyEvent(Activity.java:2431)
02-22 17:40:30.653: E/WindowManager(18524):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2071)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3960)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.ViewRootImpl.handleImeFinishedEvent(ViewRootImpl.java:3908)
02-22 17:40:30.653: E/WindowManager(18524):     at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3042)
02-22 17:40:30.653: E/WindowManager(18524):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-22 17:40:30.653: E/WindowManager(18524):     at android.os.Looper.loop(Looper.java:137)
02-22 17:40:30.653: E/WindowManager(18524):     at android.app.ActivityThread.main(ActivityThread.java:4963)
02-22 17:40:30.653: E/WindowManager(18524):     at java.lang.reflect.Method.invokeNative(Native Method)
02-22 17:40:30.653: E/WindowManager(18524):     at java.lang.reflect.Method.invoke(Method.java:511)
02-22 17:40:30.653: E/WindowManager(18524):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
02-22 17:40:30.653: E/WindowManager(18524):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
02-22 17:40:30.653: E/WindowManager(18524):     at dalvik.system.NativeStart.main(Native Method)

Пожалуйста помоги.

Спасибо.