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我已经创建了一个应用程序，该应用程序应该在用户可以登录到应用程序的数据库（mySQL）中注册新用户。我遇到的问题是，当我尝试按下按钮进行登录或注册时，出现无法将java字符串转换为JSONObject的错误。Android注册和登录应用程序错误
LoginActivity.java
package com.loginregister.loginregister;
import android.content.Intent;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
public class LoginActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
final EditText etUsername = (EditText) findViewById(R.id.etUsername);
final EditText etPassword = (EditText) findViewById(R.id.etPassword);
final Button bLogin = (Button) findViewById(R.id.bLogin);
final TextView tvRegisterHere = (TextView) findViewById(R.id.tvRegisterHere);
tvRegisterHere.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent registerIntent = new Intent(LoginActivity.this, RegisterActivity.class);
LoginActivity.this.startActivity(registerIntent);
}
});
bLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final String username = etUsername.getText().toString();
final String password = etPassword.getText().toString();
Response.Listener<String> responseListener = new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try{
JSONObject jsonResponse = new JSONObject(response);
boolean success = jsonResponse.getBoolean("success");
if(success){
String name = jsonResponse.getString("name");
int age = jsonResponse.getInt("age");
Intent intent = new Intent(LoginActivity.this, UserAreaActivity.class);
intent.putExtra("name", name);
intent.putExtra("username", username);
intent.putExtra("age", age);
LoginActivity.this.startActivity(intent);
} else{
AlertDialog.Builder builder = new AlertDialog.Builder(LoginActivity.this);
builder.setMessage("Login Failed").setNegativeButton("Retry", null).create().show();
}
} catch (JSONException e){
e.printStackTrace();
}
}
};
LoginRequest loginRequest = new LoginRequest(username, password, responseListener);
RequestQueue queue = Volley.newRequestQueue(LoginActivity.this);
queue.add(loginRequest);
}
});
}
}
LoginRequest.java
package com.loginregister.loginregister;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.toolbox.StringRequest;
import java.util.HashMap;
import java.util.Map;
/**
* Created by ---- on 2016-09-24.
*/
public class LoginRequest extends StringRequest {
private static final String LOGIN_REQUEST_URL = "Webserver with my php file";
private Map<String, String> params;
public LoginRequest(String username, String password, Response.Listener<String> listener){
super(Request.Method.POST, LOGIN_REQUEST_URL, listener, null);
params = new HashMap<>();
params.put("username", username);
params.put("password", password);
}
@Override
public Map<String, String> getParams() {
return params;
}
}
RegisterActivity.java
package com.loginregister.loginregister;
import android.content.Intent;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
public class RegisterActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
final EditText etName = (EditText) findViewById(R.id.etName);
final EditText etUsername = (EditText) findViewById(R.id.etUsername);
final EditText etPassword = (EditText) findViewById(R.id.etPassword);
final EditText etAge = (EditText) findViewById(R.id.etAge);
final Button bRegister = (Button) findViewById(R.id.bRegister);
bRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final String name = etName.getText().toString();
final String username = etUsername.getText().toString();
final String password = etPassword.getText().toString();
final int age = Integer.parseInt(etAge.getText().toString());
Response.Listener<String> responseListener = new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jsonResponse = new JSONObject(response);
boolean success = jsonResponse.getBoolean("success");
if (success){
Intent intent = new Intent(RegisterActivity.this, LoginActivity.class);
startActivity(intent);
}else{
AlertDialog.Builder builder = new AlertDialog.Builder(RegisterActivity.this);
builder.setMessage("Register Failed").setNegativeButton("Retry", null).create().show();
}
} catch (JSONException e){
e.printStackTrace();
}
}
};
RegisterRequest registerRequest = new RegisterRequest(name, username, age, password, responseListener);
RequestQueue queue = Volley.newRequestQueue(RegisterActivity.this);
queue.add(registerRequest);
}
});
}
}
RegisterRequest.java
package com.loginregister.loginregister;
import com.android.volley.Response;
import com.android.volley.toolbox.StringRequest;
import java.util.HashMap;
import java.util.Map;
/**
* Created by ---- on 2016-09-24.
*/
public class RegisterRequest extends StringRequest {
private static final String REGISTER_REQUEST_URL = "Webserver with my php file";
private Map<String, String> params;
public RegisterRequest(String name, String username, int age, String password, Response.Listener<String> listener){
super(Method.POST, REGISTER_REQUEST_URL, listener, null);
params = new HashMap<>();
params.put("name", name);
params.put("username", username);
params.put("password", password);
params.put("age", age + "");
}
@Override
public Map<String, String> getParams() {
return params;
}
}
的login.php
<?php
$con = mysqli_connect("my_host", "my_user", "my_password", "my_db");
$username = $_POST["username"];
$password = $_POST["password"];
$statement = mysqli_prepare($con, "SELECT * FROM user WHERE username = ? AND password = ?");
mysqli_stmt_bind_param($statement, "ss", $username, $password);
mysqli_stmt_execute($statement);
mysqli_stmt_store_result($statement);
mysqli_stmt_bind_result($statement, $userID, $name, $username, $age, $password);
$response = array();
$response["success"] = false;
while(mysqli_stmt_fetch($statement)){
$response["success"] = true;
$response["name"] = $name;
$response["age"] = $age;
$response["username"] = $username;
$response["password"] = $password;
}
echo json_encode($response);
?>
Register.php
<?php
$con = mysqli_connect("my_host", "my_user", "my_password", "my_db");
$name = $_POST["name"];
$age = $_POST["age"];
$username = $_POST["username"];
$password = $_POST["password"];
$statement = mysqli_prepare($con, "INSERT INTO user (name, username, age, password) VALUES (?, ?, ?, ?)");
mysqli_stmt_bind_param($statement, "siss", $name, $username, $age, $password);
mysqli_stmt_execute($statement);
$response = array();
$response["success"] = true;
echo json_encode($response);
?>
AndroidManifest.xml中
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.loginregister.loginregister">
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".LoginActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".RegisterActivity" />
<activity android:name=".UserAreaActivity"></activity>
</application>
</manifest>¨
错误日志LoginActivity
W/System.err: org.json.JSONException: Value <br><table of type java.lang.String cannot be converted to JSONObject
W/System.err: at org.json.JSON.typeMismatch(JSON.java:111)
W/System.err: at org.json.JSONObject.<init>(JSONObject.java:160)
W/System.err: at org.json.JSONObject.<init>(JSONObject.java:173)
W/System.err: at com.loginregister.loginregister.LoginActivity$2$1.onResponse(LoginActivity.java:49)
W/System.err: at com.loginregister.loginregister.LoginActivity$2$1.onResponse(LoginActivity.java:45)
W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:60)
W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
W/System.err: at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
W/System.err: at android.os.Handler.handleCallback(Handler.java:751)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err: at android.os.Looper.loop(Looper.java:154)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6077)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
错误日志RegisterActivity
W/System.err: org.json.JSONException: Value <br><table of type java.lang.String cannot be converted to JSONObject
W/System.err: at org.json.JSON.typeMismatch(JSON.java:111)
W/System.err: at org.json.JSONObject.<init>(JSONObject.java:160)
W/System.err: at org.json.JSONObject.<init>(JSONObject.java:173)
W/System.err: at com.loginregister.loginregister.RegisterActivity$1$1.onResponse(RegisterActivity.java:44)
W/System.err: at com.loginregister.loginregister.RegisterActivity$1$1.onResponse(RegisterActivity.java:40)
W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:60)
W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
W/System.err: at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
W/System.err: at android.os.Handler.handleCallback(Handler.java:751)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err: at android.os.Looper.loop(Looper.java:154)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6077)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
响应字符串没有正确的JSON –
但是，它不是在PHP文件中转换为JSON字符串吗？ echo json_encode（$ response）; – user2125673
通过REST API客户端检查你的API响应 –