php - 如何优化通过 php/android 从 mysql 获取数据？

Question

简介

我有一个应用程序，如果 google play 市场上有新版本，我想强制用户更新它。这适用于以下代码，但不是很稳定。我正在通过 AsyncTask 执行此操作并从 php 文件获取数据。但它给我的感觉是，一定有更好的方法，或者可以让它更稳定的方法。

问题

我如何为该过程设置超时，例如因为用户的互联网连接非常低？

代码

get_newest_apk.php

<?PHP

    /*  GET APK VERSION FROM ANDROID DEVICE
        Example: [PATH]/get_newest_apk.php?apkversion=6
    */
    if($_GET["apkversion"]){
        $apkversion= $_GET["apkversion"];

        //MYSQL LOGIN PARAMETERS
        $host = '*****';
        $user = '*****';
        $pass = '*****';
        $db =   '*****';

        $mysqli = new mysqli($host, $user, $pass, $db);

            $result = $mysqli->query("SELECT MAX(VERSION) FROM TBL_APK");
            $row = $result->fetch_row();
            $count = $row[0];

            if($count > $apkversion){
                //Newer APK is avaiable
                echo "1";
            }else{
                //There is no never APK avaiable
                echo "2";
            }

    }else{
        //Error by GETTING apkversion from Android device
        echo "3";
    }
?>

AsyncTask 类

class checkForNewAPK extends AsyncTask<Void, Void, String> {
    @Override
    protected void onPreExecute() {
        //Do not show the user a progress because he don't want to see it in every onResume
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        int intResult = Integer.parseInt(s);

        //strResult as intResult; 1 = Newer APK avaiable, 2 = No newer APK avaiable, 3 = Error at $_GET["apkversion"] line 6
        if(intResult == 1){
            //Force to Update App
            Log.v("APKResult: ", "1");
        }else if(intResult == 2){
            //No update needed
            Log.v("APKResult: ", "2");
        }else if(intResult == 3){
            //Error in PHP-File
            Log.v("APKResult: ", "3");
        }else{
            //Unknown error
            Log.v("APKResult: ", "Unkown Error");
        }
    }

    //in this method we are fetching the json string
    @Override
    protected String doInBackground(Void... voids) {
        try {
            int intApkVersion = getApplication().getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;
            URL url = new URL(strUrlGetNewestAPK+"?apkversion="+intApkVersion);
            String strResultFromEcho;

            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            StringBuilder strResult = new StringBuilder();

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            while ((strResultFromEcho = bufferedReader.readLine()) != null) {
                strResult.append(strResultFromEcho + "\n");
            }

            return strResult.toString().trim();
        } catch (Exception e) {
            return null;
        }
    }
}

Answer 1

How can I set a timeout to the procedure, for example because of a very low internetconnection from the user?

您需要使用 setConnectTimeout和 setReadTimeout

setConnectTimeout

• 设置指定的超时值(以毫秒为单位)，以在打开指向此 URLConnection 引用的资源的通信链接时使用。如果在建立连接之前超时到期，则会引发 java.net.SocketTimeoutException。零超时被解释为无限超时。

setReadTimeout

• 将读取超时设置为指定的超时，以毫秒为单位。非零值指定在与资源建立连接时从输入流读取时的超时。如果超时在有数据可供读取之前到期，则会引发 java.net.SocketTimeoutException。零超时被解释为无限超时。

示例代码

   HttpURLConnection con = (HttpURLConnection) url.openConnection();
   con.setConnectTimeout(3000); //set connection time out in milliseconds
   con.setReadTimeout(3000); // set read time out in milliseconds

在您的代码中进行以下更改

class checkForNewAPK extends AsyncTask<Void, Void, String> {
    @Override
    protected void onPreExecute() {
        //Do not show the user a progress because he don't want to see it in every onResume
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        int intResult = Integer.parseInt(s);

        //strResult as intResult; 1 = Newer APK avaiable, 2 = No newer APK avaiable, 3 = Error at $_GET["apkversion"] line 6
        if(intResult == 1){
            //Force to Update App
            Log.v("APKResult: ", "1");
        }else if(intResult == 2){
            //No update needed
            Log.v("APKResult: ", "2");
        }else if(intResult == 3){
            //Error in PHP-File
            Log.v("APKResult: ", "3");
        }else{
            //Unknown error
            Log.v("APKResult: ", "Unkown Error");
        }
    }

    //in this method we are fetching the json string
    @Override
    protected String doInBackground(Void... voids) {
        try {
            int intApkVersion = getApplication().getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;
            URL url = new URL(strUrlGetNewestAPK+"?apkversion="+intApkVersion);
            String strResultFromEcho;

            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            con.setConnectTimeout(3000); //set connection time outt in milliseconds
            con.setReadTimeout(3000); // set read time outt in milliseconds

            StringBuilder strResult = new StringBuilder();

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            while ((strResultFromEcho = bufferedReader.readLine()) != null) {
                strResult.append(strResultFromEcho + "\n");
            }

            return strResult.toString().trim();
        } catch (SocketTimeoutException e) {
            // this block code execute when time out exception is occur
            // you need to perform your logic here when time out exception occur
            return "Request timeout occur.\nTap on \'TRY AGAIN\' to retry";
        }
    }
}

注意:您也可以使用库进行API调用

You can use Volley library

• Volley 是一个 HTTP 库，它使 Android 应用程序的网络连接变得更容易，最重要的是，速度更快。 Volley 在 GitHub 上可用.

来自文档

Volley offers the following benefits:

• 自动安排网络请求。

• 多个并发网络连接。

• 具有标准 HTTP 缓存一致性的透明磁盘和内存响应缓存。支持请求优先级排序。

• 取消请求 API。您可以取消单个请求，也可以设置要取消的请求 block 或范围。

• 易于定制，例如重试和退避。

• 强大的顺序让您可以轻松地使用从网络异步获取的数据正确填充您的 UI。

• 调试和跟踪工具。

You can use Retrofit library

• Square, Inc. 适用于 Android 和 Java 的类型安全 HTTP 客户端。 Retrofit Github link

Retrofit vs Volley

请阅读这篇文章Comparison of Android networking libraries: OkHTTP, Retrofit, and Volley