java - Android 应用程序上传到远程服务器后崩溃？

Question

我制作了一个具有登录功能的应用程序，它将显示用户的信息。使用 localhost 工作正常，但是当我在主机上上传 PHP 时，配置文件页面崩溃了？

崩溃报告

12-18 13:36:38.023: E/AndroidRuntime(1332): FATAL EXCEPTION: main
12-18 13:36:38.023: E/AndroidRuntime(1332): java.lang.NullPointerException
12-18 13:36:38.023: E/AndroidRuntime(1332):     at com.example.itmaproject.EditContactsActivity$GetProductDetails$1.run(EditContactsActivity.java:141)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at android.os.Handler.handleCallback(Handler.java:725)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at android.os.Handler.dispatchMessage(Handler.java:92)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at android.os.Looper.loop(Looper.java:137)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at android.app.ActivityThread.main(ActivityThread.java:5041)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at java.lang.reflect.Method.invokeNative(Native Method)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at java.lang.reflect.Method.invoke(Method.java:511)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
12-18 13:36:38.023: E/AndroidRuntime(1332):     at dalvik.system.NativeStart.main(Native Method)

Java

/**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditContactsActivity.this);
            pDialog.setMessage("Loading contact details. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        /**
         * Getting product details in background thread
         * */
        protected String doInBackground(String... params) {

            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    // Check for success tag
                    int success;
                    try {
                        // Building Parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("username", username));

                        // getting product details by making HTTP request
                        // Note that product details url will use GET request
                        JSONObject json = jsonParser.makeHttpRequest(
                                url_contact_details, "GET", params);

                        // check your log for json response
                        Log.d("Single Contact Details", json.toString());

                        // json success tag
                        success = json.getInt(TAG_SUCCESS);
                        if (success == 1) {
                            // successfully received product details
                            JSONArray contactObj = json.getJSONArray(TAG_CONTACT); // JSON Array

                            // get first product object from JSON Array
                            JSONObject contact = contactObj.getJSONObject(0);

                            // product with this pid found
                            // Edit Text
                            txtName = (TextView) findViewById(R.id.inputName);
                            txtDepart = (TextView) findViewById(R.id.department);
                            //txtAbout = (TextView) findViewById(R.id.inputDesc);
                             txtUser = (TextView) findViewById(R.id.inputPrice);
                            // display product data in EditText
                            String fullname = contact.getString(TAG_LASTNAME)+' '+ contact.getString(TAG_FIRSTNAME);
                            txtName.setText(fullname);
                            txtDepart.setText(contact.getString(TAG_DEPART));
                            //txtAbout.setText(contact.getString(TAG_LASTNAME));
                            txtUser.setText(contact.getString(TAG_ID));

                            Log.v("blahhhhh", "blah hhhhblah");

                        }else{
                            // product with pid not found
                            Log.v("blah", "blah blah");
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            });

            return null;
        }


        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once got all details
            pDialog.dismiss();
        }
    }

141行

Log.d("Single Contact Details", json.toString());

PHP

text/x-generic get_contact_details.php
PHP script text

<?php

/*
 * Following code will get single product details
 * A product is identified by product id (pid)
 */

// array for JSON response
$response = array();


// include db connect class
require_once __DIR__ . '/db_connect.php';

// connecting to db
$db = new DB_CONNECT();

// check for post data
if (isset($_GET["username"])) {
    $username = $_GET['username'];

    // get a product from products table
    $result = mysql_query("SELECT * FROM accounts WHERE username = '".$username."' ");

    if (!empty($result)) {
        // check for empty result
        if (mysql_num_rows($result) > 0) {

            $result = mysql_fetch_array($result);

            $contacts = array();
            $contacts["firstname"] = $result["firstname"];
            $contacts["middlename"] = $result["middlename"];
            $contacts["lastname"] = $result["lastname"];
            $contacts["email"] = $result["email"];
             $contacts["user_id"] = $result["user_id"];
             $contacts["department"] = $result["department"];
            // success
            $response["success"] = 1;

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

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

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

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

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

    // echoing JSON response
    echo json_encode($response);
}
?>

Answer 1

从 logCat 中你得到一个空指针(java.lang.NullPointerException)

如果这是一行:

Log.d("Single Contact Details", json.toString());

那么这意味着您的服务器没有返回 JSON 数据。

还有一件事是错误的，您不应该在 doInBackground 中的控件上设置文本，而应该在主线程 onPostExecute() 中完成。因此，您实际上不需要使用 runOnUiThread，因为 AsyncTask 已经是一个具有自己的线程回调的类。

最后一件事，您正在使用已弃用的库，甚至没有转义。更糟糕的是它是一个 GET 参数。使用准备好的语句来避免 SQL 注入(inject)。 (PDO 或 mysqli)