安卓获取包名，版本号，

private String getAppInfo() {    try {        String pkName = this.getPackageName();        String versionName = this.getPackageManager().getPackageInfo(                pkName, 0).versionName;        int versionCode = this.getPackageManager()                .getPackageInfo(pkName, 0).versionCode;        return pkName + "   " + versionName + "  " + versionCode;    } catch (Exception e) {    }    return null;}