Question

我正在使用android studio，mysql数据库和notepad ++来处理php文件。该数据库有一个名为登录的表，并有3个属性：

ID
姓名
名字

所有类型都是varchar 当我尝试执行android和php的代码时，我没有收到任何错误，代码执行成功，但数据库中的数据没有显示在模拟器上。

   *******************Android code************************
package com.example.digi.college;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 import android.widget.TextView;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;

import java.util.HashMap;
 import java.util.Map;


 public class MainActivity extends AppCompatActivity {

EditText firstname, lastname, id;
Button insert, show;
TextView result;
RequestQueue requestQueue;
String inserturl = "http://192.168.1.104/android/register.php";
String displayurl = "http://192.168.1.104/android/display.php";
String hello="hello how are you";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    id = (EditText) findViewById(R.id.editText);
    firstname = (EditText) findViewById(R.id.editText2);
    lastname = (EditText) findViewById(R.id.editText3);
    insert = (Button) findViewById(R.id.button);
    show = (Button) findViewById(R.id.button2);
    result = (TextView) findViewById(R.id.textView);

    requestQueue = Volley.newRequestQueue(getApplicationContext());



    show.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {



           JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST,
                    displayurl, new Response.Listener<JSONObject>() {
                    public void onResponse(JSONObject response) {
                        try {
                            JSONArray students = response.getJSONArray("students");

                            for (int i = 0; i < students.length(); i++) {
                                JSONObject login = students.getJSONObject(i);

                                String id = login.getString("id");
                                String firstname = login.getString("firstname");
                                String lastname = login.getString("lastname");

                                result.append(id+" "+firstname+" "+lastname+"\n");

                            }
                            result.append("===\n");

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }
            }, new Response.ErrorListener() {

                public void onErrorResponse(VolleyError error) {

                }

            });
            requestQueue.add(jsonObjectRequest);
        }
    });

    insert.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            StringRequest request = new StringRequest(Request.Method.POST,    inserturl, new Response.Listener<String>() {
                @Override
                public void onResponse(String s) {

                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError volleyError) {

                }

        }){

                @Override
                protected Map<String, String> getParams() throws AuthFailureError {
                   Map<String,String> parameters = new HashMap<String, String>();
                    parameters.put("id",id.getText().toString());
                    parameters.put("firstname",firstname.getText().toString());
                    parameters.put("lastname",lastname.getText().toString());

                    return parameters;
                }
            };
            requestQueue.add(request);
        }
    });

    }

  }



 *****************Php Code for insert.php******************



<?php
 if($_SERVER["REQUEST_METHOD"] == "POST")
 {
  $id=$_POST['id'];
   $firstname = $_POST['firstname'];
  $lastname = $_POST['lastname'];

  $db = mysql_connect("localhost", "root", "");
  mysql_select_db("ntu", $db);

  $sql = mysql_query("INSERT INTO login (id,firstname,lastname) VALUES           ('$id','$firstname', '$lastname')");

 mysql_close($db);

  }

 ?>


  *************Php code for display.php*************


<?php



   $db = mysql_connect("localhost", "root", "");
   mysql_select_db("ntu", $db);


   $sql = mysql_query("SELECT * FROM login");


  $a = array(); 


   $index = 0;
  while($row = mysql_fetch_assoc($sql)) 
   {
 $a[$index] = $row;
 $index++;
   }




   echo json_encode(array("students"=>$a));
  mysql_close($db);



  ?>

Answer 1

我认为你错过了androidmanifeast.xml文件中的互联网权限，并获得了互联网许可并进行了检查。

无法在android studio中的模拟器上获取json数据

1 个答案: