Question

我正在使用PHP＆amp; amp;从我的Android应用程序连接到外部数据库JSON。它是一个简单的登录系统，如果用户名和密码存在于数据库上，它会进入Main2activity但是如果不同的用户并通过它会显示错误消息我成功连接到数据库并在浏览器中获得结果，但是虽然来到android我没有得到任何结果它显示：错误解析数据org.json.JSONException：类型java.lang.String的值无法转换为JSONArray。 以下是我的代码：

MainActivity.java：

package com.example.hussienalrubaye.mysqlsystemlogin;

import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

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

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class MainActivity extends AppCompatActivity {

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

    public void bulogin(View view) {
   //get user name and password
        EditText txtusername=(EditText)findViewById(R.id.etusername);
        EditText txtpassword=(EditText)findViewById(R.id.etpassword);
        new MyAsyncTaskresources().execute("http://l3pfe.byethost33.com/db.php?username="+txtusername.getText().toString()+"&password=" +txtpassword.getText().toString());
    }


    String result = "";
    public class MyAsyncTaskresources extends AsyncTask<String, String, String> {
        @Override
        protected void onPreExecute() {

        }
        @Override
        protected String  doInBackground(String... params) {


            InputStream isr = null;

            try{
 String URL=params[0];
                URL url = new URL( URL);
                URLConnection urlConnection = url.openConnection();
                isr  = new BufferedInputStream(urlConnection.getInputStream());

            }

            catch(Exception e){

                Log.e("log_tag", "Error in http connection " + e.toString());



            }

//convert response to string

            try{

                BufferedReader reader = new BufferedReader(new InputStreamReader(isr,"iso-8859-1"),8);

                StringBuilder sb = new StringBuilder();

                String line = null;

                while ((line = reader.readLine()) != null) {

                    sb.append(line + "\n");

                }

                isr.close();

                result=sb.toString();

            }

            catch(Exception e){

                Log.e("log_tag", "Error  converting result " + e.toString());

            }

//parse json data


            return null;
        }

        protected void onPostExecute(String  result2){
            try {

                String s = "";

                JSONArray jArray = new JSONArray(result);

                for (int i = 0; i < jArray.length(); i++) {

                    JSONObject json = jArray.getJSONObject(i);

                    s = s + "login info : " + json.getString("id") + " " + json.getString("username") + " " + json.getString("password");
                break;}
                if(s.length()>0){
                    Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show();
                Intent in=new Intent(getApplicationContext(),Main2Activity.class);
                startActivity(in);}
                else
                    Toast.makeText(getApplicationContext(),"user name or password isnot correct",Toast.LENGTH_LONG).show();


            } catch (Exception e) {

// TODO: handle exception

                Log.e("log_tag", "Error Parsing Data "+e.toString());

            }
        }




    }
}

Main2Activity.java：

package com.example.hussienalrubaye.mysqlsystemlogin;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

}

activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true">

        <LinearLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal">

            <EditText
                android:hint="Enter user name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:inputType="textPersonName"
                android:ems="10"
                android:id="@+id/etusername" />
        </LinearLayout>

        <LinearLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"></LinearLayout>

        <EditText
            android:hint="Enter password"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:inputType="textPassword"
            android:ems="10"
            android:id="@+id/etpassword" />

        <LinearLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal">

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Login"
                android:id="@+id/button"
                android:onClick="bulogin" />
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

activity_main2.xml：

    <?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout
        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" android:fitsSystemWindows="true"
        tools:context="com.example.hussienalrubaye.mysqlsystemlogin.Main2Activity">

        <android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
            android:layout_width="match_parent" android:theme="@style/AppTheme.AppBarOverlay">

            <android.support.v7.widget.Toolbar android:id="@+id/toolbar"
                android:layout_width="match_parent" android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.AppBarLayout>

        <include layout="@layout/content_main2" />

        <android.support.design.widget.FloatingActionButton android:id="@+id/fab"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:layout_gravity="bottom|end" android:layout_margin="@dimen/fab_margin"
            android:src="@android:drawable/ic_dialog_email" />

    </android.support.design.widget.CoordinatorLayout>
***content_main2.xml :***
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/activity_main2"
    tools:context="com.example.hussienalrubaye.mysqlsystemlogin.Main2Activity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="my control pannel"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

db.php：

    <?php

mysql_connect("sql306.byethost33.com","b33_19513012","loool");//change server name  //pass username according your settings

mysql_select_db("b33_19513012_pfe");// also chang the Mysql database name


$sql1=mysql_query("select * from admins WHERE username ='" . $_GET['username'] . "' and password='" . $_GET['password'] ."'"); //querstirng

if (!$sql1) {

echo "Could not successfully run query ($sql) from DB: " . mysql_error();

exit;

}

while($row=mysql_fetch_assoc($sql1))

$output[]=$row;



print(json_encode($output));// this will print the output in json

mysql_close();

?>

Answer 1

我很乐意警告你，mysql_connect已被弃用，PHP 7再也没有mysql_connect。请改用mysqli。

正如mysql_connect doc所说，您应该指定连接链接。检查$link变量。

$link = mysql_connect("sql306.byethost33.com", "b33_19513012", "loool");//change server name  //pass username according your settings
mysql_select_db("b33_19513012_pfe", $link);// also chang the Mysql database name
$sql1 = mysql_query("select * from admins WHERE username ='" . $_GET['username'] . "' and password='" . $_GET['password'] . "'", $link); //querstirng

if (!$sql1) {
    echo "Could not successfully run query ($sql) from DB: " . mysql_error($link);
    exit;
}

while ($row = mysql_fetch_assoc($sql1)) {
    $output[] = $row;
}
print(json_encode($output));// this will print the output in json

mysql_close($link);

祝你好运！

使用JSON＆amp; amp;将DB Mysql与Android应用程序连接起来PHP

1 个答案: