我是Android上的新手，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Android-MySql通过PHP页面交互的教程（使用JSON），但是输出有问题（例如，如何将我从JSON获得的内容转换为String？）。为了让您更好地理解这个问题，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Manifest中我插入了Internet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String中获得的标题和描述？
非常感谢你的帮助！
@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
并且第158行是：
String title = obj.getString("title");
答案 0 :(得分：1)
所以你几乎得到了它。实际上，您的makeHttpRequest()方法会返回JSONObject脚本返回的PHP。
现在您只需要解析JSON并从中检索并保存值。
此解决方案为伪代码：
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");