Java 如何在不使用xml的情况下向游戏中添加广告？

我想在我的游戏中添加广告，但我不使用xml。我知道我应该学习，但是，这是我的第一个游戏，我只是想先发布它。这就是我目前所拥有的。我也一直跟踪到说编辑main_activity.xml的部分。我现在应该如何添加广告

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //fullscreen
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.Flag_FULLSCREEN);

    //scale image
    Display display = getWindowManager().getDefaultDisplay();
    size = new Point();
    dispay.getSize(size);
    dispX = size.x;
    dispY = size.y;
    bg = Bitmap.createScaledBitmap(BitmapFactory.decodeResource(
            getResources(), R.drawable.bg),dispX,dispY,true);
    bg = Bitmap.createScaledBitmap(BitmapFactory.decodeResource(
            getResources(), R.drawable.losescreen),GamePanel.rescaleX(805),GamePanelrescaleY(1105),true);
    bg = Bitmap.createScaledBitmap(BitmapFactory.decodeResource(
            getResources(), R.drawable.playbutton),GamePanel.rescaleX(242),GamePanelrescaleY(242),true);

    setContentView(new GamePanel(this));
    contextOfApplication = getApplicationContext();
}

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此代码替代了在xml中添加adview：

AdView adView = new AdView(this, AdSize.BANNER, MY_AD_UNIT_ID);
// Lookup the layout where you want to place the ad unit
// give the layout an id in the layout xml
LinearLayout layout = (LinearLayout)findViewById(R.id.mainLayout);
// Add the adView to the activity's layout
layout.addView(adView);

以下代码的其余部分请参见教程