在执行php文件之前检索数据_Php_Android

在执行php文件之前检索数据

php android

在执行php文件之前检索数据,php,android,Php,Android,如何在android中检索textView文本，以便.php文件在预执行php文件之前将其作为“$\u ID”的ID读取？因为在我的php文件中，我需要在执行json数组之前从我的android studio中检索一个ID，至少在我得到的错误中是这样认为的我是编程新手，所以请在你还是编程新手的时候解释一下这是我的php代码： <?php $host='localhost'; $user='root'; $password=''; $db='employee101'; $_id = $_

如何在android中检索textView文本，以便.php文件在预执行php文件之前将其作为“$\u ID”的ID读取？因为在我的php文件中，我需要在执行json数组之前从我的android studio中检索一个ID，至少在我得到的错误中是这样认为的

我是编程新手，所以请在你还是编程新手的时候解释一下

这是我的php代码：

<?php
$host='localhost';
$user='root';
$password='';
$db='employee101';
$_id = $_POST['id'];

$sql = "select * from employee_comments where id = $_id;";

$con = mysqli_connect($host,$user,$password,$db);

$result = mysqli_query($con, $sql);

$response = array();

while($row = mysqli_fetch_array($result)){

    array_push($response,array("id"=>$row[0],"comment"=>$row[1],"rating"=>$row[2]));

}

echo json_encode(array("server_respo"=>$response));

mysqli_close($con);




?>

PHP中的错误：

注意：C:\wamp64\www\json\u comments.php中的未定义索引：id 6注意：未定义变量：中的响应 C:\wamp64\www\json\u comments.php第25行注意：未定义变量：C:\wamp64\www\json\u comments.php第27行的con警告： mysqli_close期望参数1为mysqli，在第27行的C:\wamp64\www\json\u comments.php

您需要在条件中包装代码

if (!empty($_POST['id'])) {
  # place your code here
}

编辑

首先，u无法在asynctask内的textview中设置值，因为所有与ui相关的操作只能在ui线程上完成，请参见下文

基于Paresh：使用runUnuithRead方法。如果您想在代码中读写文本，您可以执行以下操作：

public class MainActivity extends AppCompatActivity {

String Json_STRING;
TextView textView;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView=findViewById(R.id.text_view_id);
    String text=textview.getText();
    new BackgroundTask().execute(text);
     //new line


}




/*public void getJSON(View view) {

    new BackgroundTask().execute();

}*/

// change first param of asynctask to String to accept array of string params

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

    String json_url;
    String JSON_STRING;

    @Override
    protected void onPreExecute() {

        json_url = "http://10.0.2.2/json_comments.php";
    }

    @Override
    protected String doInBackground(String... params) {
        try {
String param=params[0]; // you can access text of textview from here and pass it to your url like "json_url?id=param"
            URL url = new URL(json_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            while ((JSON_STRING = bufferedReader.readLine()) != null) {

                stringBuilder.append(JSON_STRING + "\n");
            }

            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return stringBuilder.toString().trim();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String result) {
        runOnUiThread(new Runnable() {
           @Override
           public void run() {
              textView.setText(result);       
           }
        });
    }

}

php android

在php文件中，您可以从$u POST['ID']获取ID。所以，在Java文件中，HttpURLConnection HttpURLConnection需要使用方法POST，并将数据ID发送到php文件

import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

    String Json_STRING;
    TextView textView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new BackgroundTask().execute();
        //new line


    }




    /*public void getJSON(View view) {

        new BackgroundTask().execute();

    }*/


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

        String json_url;
        String JSON_STRING;

        @Override
        protected void onPreExecute() {

            json_url = "http://10.0.2.2/json_comments.php";
        }

        @Override
        protected String doInBackground(Void... params) {
            try {

                String urlParameters  = "id=your_id";
                byte[] postData       = urlParameters.getBytes( StandardCharsets.UTF_8 );
                int    postDataLength = postData.length;
                String request        = json_url;;
                URL    url            = new URL( request );
                HttpURLConnection conn= (HttpURLConnection) url.openConnection();
                conn.setDoOutput( true );
                conn.setInstanceFollowRedirects( false );
                conn.setRequestMethod( "POST" );
                conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded");
                conn.setRequestProperty( "charset", "utf-8");
                conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength ));
                conn.setUseCaches( false );
                try( DataOutputStream wr = new DataOutputStream( conn.getOutputStream())) {
                    wr.write( postData );
                }

                if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){
                    is = urlConn.getInputStream();
                    BufferedReader in = new BufferedReader(new InputStreamReader(is));
                    StringBuilder stringBuilder = new StringBuilder();
                    while ((inputLine = in.readLine()) != null)
                        stringBuilder.append(inputLine + "\n");
                    in.close();
                    return stringBuilder.toString().trim();



                    //Your code read data return here ...

                } else {
                    is = urlConn.getErrorStream();
                }

                return null;


            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
        }

        @Override
        protected void onPostExecute(String result) {
            TextView textView = (TextView)findViewById(R.id.textView2);
            textView.setText(result);
            Json_STRING = result;
        }

    }

我应该把那个条件放在哪里，你们能告诉我吗？更新答案，保持线路的其余部分不变。它将不会执行你的代码，直到它有idI仍然有相同的错误，未定义的变量thingy与id：我如何做rununui thingy，你能指导我如何做，我对编程非常陌生，只需在postExecute中使用上述代码，因为它将超出android的主UI线程，然后可以访问此线程上的所有元素，并且所有视图都位于此线程上。我在您的oncreate textView=findviewbydr.id.text\u view\u id中遇到错误；String text=textview.getText；。它表示不兼容的类型字符串text=textview.getText.toString；并确保您将xml中textview的id设置为与java文件相同，并且变量'result'是从内部类中访问的，需要声明为finalupdated my answer，只需将代码替换为file@RizalJulianBlanco，将其置于受保护字符串doInBackgroundVoid。。。params，替换try-catch块。

if (!empty($_POST['id'])) {
  # place your code here
}

<?php 
$host='localhost';
$user='root';
$password='';
$db='employee101';

if (!empty($_POST['id'])) {
    $_id = $_POST['id'];

    $sql = "select * from employee_comments where id = $_id;";

    $con = mysqli_connect($host,$user,$password,$db);

    $result = mysqli_query($con, $sql);

    $response = array();

    while($row = mysqli_fetch_array($result)){

        array_push($response,array("id"=>$row[0],"comment"=>$row[1],"rating"=>$row[2]));

    }

echo json_encode(array("server_respo"=>$response));

mysqli_close($con);

}
?>

public class MainActivity extends AppCompatActivity {

String Json_STRING;
TextView textView;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView=findViewById(R.id.text_view_id);
    String text=textview.getText();
    new BackgroundTask().execute(text);
     //new line


}




/*public void getJSON(View view) {

    new BackgroundTask().execute();

}*/

// change first param of asynctask to String to accept array of string params

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

    String json_url;
    String JSON_STRING;

    @Override
    protected void onPreExecute() {

        json_url = "http://10.0.2.2/json_comments.php";
    }

    @Override
    protected String doInBackground(String... params) {
        try {
String param=params[0]; // you can access text of textview from here and pass it to your url like "json_url?id=param"
            URL url = new URL(json_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();
            while ((JSON_STRING = bufferedReader.readLine()) != null) {

                stringBuilder.append(JSON_STRING + "\n");
            }

            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return stringBuilder.toString().trim();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String result) {
        runOnUiThread(new Runnable() {
           @Override
           public void run() {
              textView.setText(result);       
           }
        });
    }

}

import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

    String Json_STRING;
    TextView textView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new BackgroundTask().execute();
        //new line


    }




    /*public void getJSON(View view) {

        new BackgroundTask().execute();

    }*/


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

        String json_url;
        String JSON_STRING;

        @Override
        protected void onPreExecute() {

            json_url = "http://10.0.2.2/json_comments.php";
        }

        @Override
        protected String doInBackground(Void... params) {
            try {

                String urlParameters  = "id=your_id";
                byte[] postData       = urlParameters.getBytes( StandardCharsets.UTF_8 );
                int    postDataLength = postData.length;
                String request        = json_url;;
                URL    url            = new URL( request );
                HttpURLConnection conn= (HttpURLConnection) url.openConnection();
                conn.setDoOutput( true );
                conn.setInstanceFollowRedirects( false );
                conn.setRequestMethod( "POST" );
                conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded");
                conn.setRequestProperty( "charset", "utf-8");
                conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength ));
                conn.setUseCaches( false );
                try( DataOutputStream wr = new DataOutputStream( conn.getOutputStream())) {
                    wr.write( postData );
                }

                if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){
                    is = urlConn.getInputStream();
                    BufferedReader in = new BufferedReader(new InputStreamReader(is));
                    StringBuilder stringBuilder = new StringBuilder();
                    while ((inputLine = in.readLine()) != null)
                        stringBuilder.append(inputLine + "\n");
                    in.close();
                    return stringBuilder.toString().trim();



                    //Your code read data return here ...

                } else {
                    is = urlConn.getErrorStream();
                }

                return null;


            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
        }

        @Override
        protected void onPostExecute(String result) {
            TextView textView = (TextView)findViewById(R.id.textView2);
            textView.setText(result);
            Json_STRING = result;
        }

    }