Android获取应用程序的版本名称和版本号

[code]
    /**
     * 获取版本号
     * @return
     */
    public int getVersionCode(){
        PackageManager manager = getPackageManager();//获取包管理器
        try {
            //通过当前的包名获取包的信息
            PackageInfo info = manager.getPackageInfo(getPackageName(),0);//获取包对象信息
            return  info.versionCode;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 获取坂本明
     * @return
     */
    public String getVersionName(){
        PackageManager manager = getPackageManager();
        try {
            //第二个参数代表额外的信息，例如获取当前应用中的所有的Activity
            PackageInfo packageInfo = manager.getPackageInfo(getPackageName(), PackageManager.GET_ACTIVITIES
            );
            ActivityInfo[] activities = packageInfo.activities;
            showActivities(activities);
            return packageInfo.versionName;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return "";
    }
    public void showActivities(ActivityInfo[] activities){
        for(ActivityInfo activity : activities) {
            Log.i("activity=========", activity.name);
        }
    }