从 Mysql 数据库获取数据到 Android

Question

我正在尝试将 user_details 从 mysql 获取到我的 android 应用程序。为此，我从 android 发布数据，并在我的 php 页面中通过 $_POST['mobile'] 和 $_POST['usertype'] 方法获取值。要检查数据是否正在发布，我首先尝试了下面的插入语句

//this works 

$mobile = $_POST['mobile'];
$usertype = $_POST['usertype'];
sql = "INSERT INTO etc(id, etc) VALUES('$mobile', '$usertype')"

它工作正常，这意味着我的 post 方法正在发送数据。 但是，当我尝试使用下面 where 语句中的发布值来读取数据时，它不会将任何数据返回到我的应用程序

// this doesn't work

$mobile = $_POST['mobile'];
$usertype = $_POST['usertype'];
$sql = "SELECT * FROM users where mobile_number='$mobile' and user_type='$usertype'";

如果我像下面这样硬编码两个变量并使用相同的 它正在向我的应用程序返回数据

//this returning data to my application

$mobile = 1812043433;
$usertype = Driver;
$sql = "SELECT * FROM users where mobile_number='$mobile' and user_type='$usertype'";

我在这里做错了什么

这是我的php页面

  $mobile = $_POST['mobile'];
  $usertype = $_POST['usertype'];

  // Create connection
  $con=mysqli_connect("**","***","**","**");

  // Check connection
 if (mysqli_connect_errno())
 {
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
 }

 $sql = "SELECT * FROM users where mobile_number='$mobile' and user_type='$usertype'";

  if ($result = mysqli_query($con, $sql))
   {
   $resultArray = array();
   $tempArray = array();

   while($row = $result->fetch_object())
   {
   // Add each result into the results array
   $tempArray = $row;
   array_push($resultArray, $tempArray);
   }
   echo json_encode($resultArray);
   }
   // Close connections
   mysqli_close($con);

这是我正在解析的 android

private void downloadJSON(final String urlWebService) {

    class DownloadJSON extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }


        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            // Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
            // Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).setText("Posting Bid");

            try {
                loadIntoListView(s);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        @Override
        protected String doInBackground(Void... voids) {
            try {
                URL url = new URL(urlWebService);
                HttpURLConnection con = (HttpURLConnection) url.openConnection();
                StringBuilder sb = new StringBuilder();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
                String json;
                while ((json = bufferedReader.readLine()) != null) {
                    sb.append(json + "\n");
                }
                return sb.toString().trim();
            } catch (Exception e) {
                return null;
            }
        }
    }
    DownloadJSON getJSON = new DownloadJSON();
    getJSON.execute();
}

private void loadIntoListView(String json) throws JSONException {

    JSONArray jsonArray = new JSONArray(json);
    String[] stocks = new String[jsonArray.length()];
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject obj = jsonArray.getJSONObject(i);

        //stocks[i] = obj.getString("name") + " " + obj.getString("price");
        String driverid=stocks[i] = obj.getString("id");
        String driverfname=stocks[i] = obj.getString("first_name");
        String driverlname=stocks[i] = obj.getString("last_name");
        String driveravator="url";
        String driverratings="3.8";

        /*
        tvhiddendriverId.setText(driverid);
        tvhiddendriverfName.setText(driverfname);
        tvhiddendriverlName.setText(driverlname);
        tvhiddendriverAvator.setText(driveravator);
        tvhiddendriverRatings.setText(driverratings);*/

        /*Inserting to SQLITE directly from here

        this.deleteDatabase("ContactsDB"); 

        ContactsDB db=new ContactsDB(this);
        db.open();
        db.createEntry(driverid,driverfname,driverlname,driveravator,driverratings);
        db.close();
        Toast.makeText(this, "saved to db", Toast.LENGTH_SHORT).show();

     }
}

Answer 1

嗯....我们这里有 2 个部分。将数据插入我们的数据库的 API：

 <?php
 $mobile = $_GET['mobile'];
 $usertype = $_GET['usertype'];

  // Create connection
  $con=mysqli_connect("localhost","root","","test");

  // Check connection
 if (mysqli_connect_errno())
 {
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
 }

 $sql = "INSERT into users (mobile_number, user_type) VALUES ('$mobile','$usertype')";

 if ($con->query($sql) === TRUE) {
     echo "New record created";
 } else {
     echo "Error: ";
 }

 $con->close();
?>

还有另一个 API 可以将数据返回给我们：

<?php
 $mobile = $_GET['mobile'];
 $usertype = $_GET['usertype'];

  // Create connection
  $con=mysqli_connect("localhost","root","","test");

  // Check connection
 if (mysqli_connect_errno())
 {
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
 }

 $sql = "SELECT * FROM users where mobile_number='$mobile' and user_type='$usertype'";

  if ($result = mysqli_query($con, $sql))
   {
   $resultArray = array();
   $tempArray = array();

   while($row = $result->fetch_object())
   {
   // Add each result into the results array
   $tempArray = $row;
   array_push($resultArray, $tempArray);
   }
   echo json_encode($resultArray);
   }
   // Close connections
   mysqli_close($con);

?>

好吧，我们已经完成了 API 部分。现在我们需要完成android部分。要在数据库中插入用户，首先需要将Volley 添加到您的程序中：

dependencies {
    ...
    implementation 'com.android.volley:volley:1.1.1'
}

要使用 Volley，您必须将 android.permission.INTERNET 权限添加到应用的清单中。没有这个，您的应用将无法连接到网络。

RequestQueue queue = Volley.newRequestQueue(this);
String url ="YOUR_TARGET_URL";

// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
    @Override
    public void onResponse(String response) {
         //get your response and parse it with Gson
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        // Something went wrong
    }
});

// Add the request to the RequestQueue.
queue.add(stringRequest);