在php连接和mysql连接中单击登录按钮时应用程序崩溃
我正在尝试创建一个登录活动,在这里我验证并检查值是否正确且不为空。请帮助我。。。在这里,我用以下代码单击登录按钮,我的应用程序崩溃。请先帮我谢谢。 我是android studio编程新手,请耐心等待,谢谢 LoginActivity.java在php连接和mysql连接中单击登录按钮时应用程序崩溃,php,android,mysql,android-studio,Php,Android,Mysql,Android Studio,我正在尝试创建一个登录活动,在这里我验证并检查值是否正确且不为空。请帮助我。。。在这里,我用以下代码单击登录按钮,我的应用程序崩溃。请先帮我谢谢。 我是android studio编程新手,请耐心等待,谢谢 LoginActivity.java package com.map.laurence.dbtest; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.uti
package com.map.laurence.dbtest;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
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 org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
public class Login extends AppCompatActivity {
EditText user,pass;
Button login,register;
String loginUrl = "http://192.168.56.1/login.php";
RequestQueue requestQueue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
register = (Button) findViewById(R.id.btnRegister);
login = (Button) findViewById(R.id.btnLogin);
user = (EditText) findViewById(R.id.user);
pass = (EditText) findViewById(R.id.pass);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(Login.this, "You clicked insert", Toast.LENGTH_LONG).show();
StringRequest request = new StringRequest(Request.Method.POST, loginUrl, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
System.out.println(response.toString());
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> parameters = new HashMap<String, String>();
parameters.put("user", user.getText().toString());
return parameters;
}
};
requestQueue.add(request);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST,
loginUrl, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
System.out.println(response.toString());
Toast.makeText(Login.this, "You clicked Login", Toast.LENGTH_LONG).show();
try {
JSONArray students = response.getJSONArray("user");
for (int i = 0; i < students.length(); i++) {
JSONObject student = students.getJSONObject(i);
String user = student.getString("username");
String password = student.getString("password");
String access = student.getString("access");
if (user != null) {
if (password == pass.toString()) {
Toast.makeText(Login.this, "not null", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(Login.this, "password incorrect", Toast.LENGTH_LONG).show();
}
} else {
Toast.makeText(Login.this, "its null", Toast.LENGTH_LONG).show();
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
System.out.append(error.getMessage());
}
});
requestQueue.add(jsonObjectRequest);
}
});
}
}
package com.map.laurence.dbtest;
导入android.support.v7.app.AppActivity;
导入android.os.Bundle;
导入android.util.Log;
导入android.view.view;
导入android.widget.Button;
导入android.widget.EditText;
导入android.widget.Toast;
导入com.android.volley.AuthFailureError;
导入com.android.volley.Request;
导入com.android.volley.RequestQueue;
导入com.android.volley.Response;
导入com.android.volley.VolleyError;
导入com.android.volley.toolbox.JsonObjectRequest;
导入com.android.volley.toolbox.StringRequest;
导入org.json.JSONArray;
导入org.json.JSONException;
导入org.json.JSONObject;
导入java.util.HashMap;
导入java.util.Map;
公共类登录扩展了AppCompatActivity{
编辑文本用户,通过;
按钮登录、注册;
字符串loginUrl=”http://192.168.56.1/login.php";
请求队列请求队列;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u登录);
寄存器=(按钮)findViewById(R.id.btnRegister);
登录=(按钮)findViewById(R.id.btnLogin);
user=(EditText)findViewById(R.id.user);
pass=(EditText)findViewById(R.id.pass);
login.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
Toast.makeText(Login.this,“您单击了插入”,Toast.LENGTH_LONG.show();
StringRequest=newStringRequest(request.Method.POST、loginUrl、new Response.Listener()){
@凌驾
公共void onResponse(字符串响应){
System.out.println(response.toString());
}
},new Response.ErrorListener(){
@凌驾
公共无效onErrorResponse(截击错误){
}
}) {
@凌驾
受保护的映射getParams()引发AuthFailureError{
映射参数=新的HashMap();
parameters.put(“user”,user.getText().toString());
返回参数;
}
};
添加(请求);
JsonObjectRequest JsonObjectRequest=新的JsonObjectRequest(Request.Method.POST,
loginUrl,新的Response.Listener(){
@凌驾
公共void onResponse(JSONObject响应){
System.out.println(response.toString());
Toast.makeText(Login.this,“您点击了登录”,Toast.LENGTH_LONG.show();
试一试{
JSONArray students=response.getJSONArray(“用户”);
for(int i=0;i
布局文件login.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.map.laurence.dbtest.Login">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="50sp"
android:id="@+id/user"
android:hint="Username"/>
<EditText
android:layout_width="match_parent"
android:layout_height="50sp"
android:id="@+id/pass"
android:hint="Password"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btnLogin"
android:text="LOGIN"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btnRegister"
android:text="REGISTER"/>
</LinearLayout>
</RelativeLayout>
login.php
<?php
if($_SERVER["REQUEST_METHOD"]=="POST"){
include 'connection.php';
loginStudent();
}
function loginStudent()
{
$user = $_POST["user"];
$pass = $_POST["pass"];
global $connect;
$query = "select * from user where username='$user';";
$result = mysqli_query($connect,$query);
$number_of_rows = mysqli_num_rows($result);
$temp_array = array();
if($number_of_rows > 0 ){
while($row = mysqli_fetch_assoc($result)){
$temp_array[] = $row;
}
}
header('Content-Type: application/json');
echo json_encode(array("students"=>$temp_array));
mysqli_close($connect);
}
?>
此行负责NullPointerException。
您正在对空对象调用requestQueue.add(request)方法
首先初始化requestQueue对象,如下面的示例代码所示
RequestQueue requestQueue = VolleySingleton.getInstance(this).getRequestQueue();
把你的Logcat放进去。刚刚用错误siri更新了它。我想你忘了初始化requestQueue参数。我应该把它当作字符串值吗?
RequestQueue requestQueue = VolleySingleton.getInstance(this).getRequestQueue();