获取Android程序内AndroidManifest.xml的version

public static  String getVersionName()   
{  
    try {  
        ComponentName comp = new ComponentName(this , class );  
        PackageInfo pinfo = m_asphalt3.getPackageManager().getPackageInfo(comp.getPackageName(), 0);  
        return pinfo.versionName;  
    } catch (android.content.pm.PackageManager.NameNotFoundException e) {   
        return null;  
    }  
}