啥也不是，直接看代码

public int getVersionCode(){
    int versionCode = 0;
    try {
        PackageInfo packageInfo = getPackageManager().getPackageInfo(getPackageName(),0);
        versionCode = packageInfo.versionCode;
    } catch (PackageManager.NameNotFoundException e) {
        e.printStackTrace();
    }
    return versionCode;
}