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我是 Android 新手，我正在尝试将我的 android 应用程序连接到我的本地服务器 phpmyadmin。我已经看过一些关于通过 PHP 页面（使用 JSON）交互 Android-MySql 的教程，但是我的输出有问题（例如，如何将我从 JSON 获得的内容转换为字符串？）。为了让您更好地理解问题，这是我的代码：

JSONParser.java

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
        List<NameValuePair> params) {

    // Making HTTP request
    try {

        // check for request method
        if(method == "POST"){
            // request method is POST
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            // request method is GET
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        }           


    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

}
}

这是我的 PHP 文件“get_product.php”（数据库连接工作正常）：

<?php

$response = array();
require_once __DIR__ . '/db_connect.php';
$db = new DB_CONNECT();

if (isset($_GET["ID"])) {
$ID_work = $_GET['ID'];

$result = mysql_query("SELECT * FROM PRODUCTS WHERE ID = $ID");

if (!empty($result)) {
    if (mysql_num_rows($result) > 0) {

        $result = mysql_fetch_array($result);

        $product = array();
        $product["ID"] = $result["ID"];
        $product["title"] = $result["title"];
        $product["description"] = $result["description"];

        // success
        $response["success"] = 1;

        // user node
        $response["product"] = array();

        array_push($response["product"], $product);

        // echoing JSON response
        echo json_encode($response);
    } else {
        // no product found
        $response["success"] = 0;
        $response["message"] = "No product found";

        // echo no users JSON
        echo json_encode($response);
    }
} else {
    // no product found
    $response["success"] = 0;
    $response["message"] = "No product found";

    // echo no users JSON
    echo json_encode($response);
}
} else {
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";

echo json_encode($response);
}

?>

在清单中，我插入互联网权限，现在，在我的活动中，我插入：

private static String url = "http://IP_ADDRESS/connect/get_product.php";

但是现在如何保存在字符串中获得的标题和描述？

非常感谢您的帮助！

@Sajmon：这是 LogCat

05-13 19:53:32.322: E/JSON Parser(10336): Error parsing data org.json.JSONException: Value <HTML><HEAD><TITLE> of type java.lang.String cannot be converted to JSONObject
05-13 19:53:32.322: D/AndroidRuntime(10336): Shutting down VM
05-13 19:53:32.322: W/dalvikvm(10336): threadid=1: thread exiting with uncaught exception (group=0x4001d578)
05-13 19:53:32.332: E/AndroidRuntime(10336): FATAL EXCEPTION: main
05-13 19:53:32.332: E/AndroidRuntime(10336): java.lang.RuntimeException: Unable to start activity ComponentInfo{package/package.MyActivity}: java.lang.NullPointerException
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1659)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread.access$1500(ActivityThread.java:121)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.os.Looper.loop(Looper.java:138)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread.main(ActivityThread.java:3701)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at java.lang.reflect.Method.invokeNative(Native Method)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at java.lang.reflect.Method.invoke(Method.java:507)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at dalvik.system.NativeStart.main(Native Method)
05-13 19:53:32.332: E/AndroidRuntime(10336): Caused by: java.lang.NullPointerException
05-13 19:53:32.332: E/AndroidRuntime(10336):    at package.MyActivity.onCreate(MyActivity.java:158)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-13 19:53:32.332: E/AndroidRuntime(10336):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
05-13 19:53:32.332: E/AndroidRuntime(10336):    ... 11 more

第 158 行是：

String title = obj.getString("title");
4

1 回答 1

1

所以你几乎明白了。实际上，您的makeHttpRequest()方法返回JSONObject从PHP脚本返回。

现在您只需要解析JSON并从中检索和保存值。

这是伪代码的解决方案：

JSONParser parser = new JSONParser();
JSONObject obj = parser.makeHttpRequest("GET", <url>, <params>);
// getting data from JSON
String title = obj.getString("title");
String decription = obj.getString("description");
于 2013-05-13T16:52:04.570 回答