Android 如何在AndEngine中实现广告

我想用startApp在AndEngine上展示一则广告

像这样,

@Override
protected void onSetContentView() 
{
    StartAppAd.init(this, "apiID", "appID");            

    RelativeLayout relativeLayout = new RelativeLayout(this);
    RelativeLayout.LayoutParams layoutParams1 = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.MATCH_PARENT);
    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams( RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    layoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
    layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);

    BannerStandard startAppBanner = new BannerStandard(this);

    relativeLayout.addView(startAppBanner, layoutParams);


    this.addContentView(relativeLayout, layoutParams1); 
}

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但这不管用，请帮帮我。我几乎完成了其他设置，比如添加jar和清单文件。

logcat说“nullpointerexception”，空指针异常在哪里？张贴stacktrace