android项目获取版本号

private String getVersion(){
        //得到包管理器
        PackageManager packageManager = getPackageManager();
        PackageInfo packageInfo = null;
        try {
            //传入包名
            packageInfo = packageManager.getPackageInfo(getPackageName(),0);
            
        } catch (NameNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return packageInfo.versionName;
        
        
        
    }