Android获取本应用的版本号

public String getVersion() {    PackageManager manager = this.getPackageManager();    try {        PackageInfo info = manager.getPackageInfo(this.getPackageName(),0);        String version = info.versionName;        return version;    } catch (PackageManager.NameNotFoundException e) {        e.printStackTrace();    }    return String.valueOf(5);}