Android通过PHP和MySQL注册表格

Question

I'm going to create a simple register form app that when user insert their username and password , EditText in UI shows the id of their record in database.

My app insert users into database correctly; Just my EditText doesn't show id ...

activity_main.xml

<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:background="#00aeef"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="50dp"
    android:layout_marginTop="18dp"
    android:text="Register Example"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/textView3"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="45dp"
    android:text="Username:"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<EditText
    android:id="@+id/edt_username"
    android:layout_width="250dp"
    android:layout_height="40dp"
    android:layout_below="@+id/textView3"
    android:layout_centerHorizontal="true"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" >

    <requestFocus />
</EditText>

<Button
    android:id="@+id/btn_insert"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/edt_result"
    android:layout_below="@+id/edt_password"
    android:layout_marginTop="16dp"
    android:background="#ffffff"
    android:text="Insert"
    android:textColor="#00aeef" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/textView1"
    android:layout_below="@+id/edt_username"
    android:text="Password:"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<EditText
    android:id="@+id/edt_password"
    android:layout_width="250dp"
    android:layout_height="40dp"
    android:layout_alignLeft="@+id/edt_username"
    android:layout_below="@+id/textView2"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" />

<EditText
    android:id="@+id/edt_result"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:layout_below="@+id/btn_insert"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="22dp"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" />

</RelativeLayout>

InsertClass.java

package com.example.testphp;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;

public class InsertClass extends AsyncTask<String, Void, String>{

private Context context;
private ProgressDialog pDialog;
private EditText edt;
private String json = "";   
private JSONObject jObj = null;

public InsertClass(Context context, EditText edt)
{
    this.context = context;
    pDialog = new ProgressDialog(context);
    this.edt = edt;
}

@Override
protected void onPreExecute() {
    pDialog.setMessage("Loading... Please wait");
    pDialog.show();
    super.onPreExecute();
}

@Override
protected String doInBackground(String... arg0) {

    try
    {
    String username = (String)arg0[0];
    String password = (String)arg0[1];
    String link = "http://10.0.2.2:8020/test/test.php";
    String data = URLEncoder.encode("username","utf-8") + 
    "=" + URLEncoder.encode(username,"utf-8");
    data += "&" + URLEncoder.encode("password","utf-8") + 
            "=" + URLEncoder.encode(password,"utf-8");
    URL url = new URL(link);
    URLConnection conn = url.openConnection();
    conn.setDoOutput(true);
    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(data);
    wr.flush();
    BufferedReader reader = new BufferedReader
            (new InputStreamReader(conn.getInputStream()));
    StringBuilder sb = new StringBuilder();
    String line = null;
    while((line = reader.readLine()) != null)
    {
        sb.append(line);
        break;
    }
    json = sb.toString();
    jObj = new JSONObject(json);
    edt.setText(jObj.getString("id"));
    return sb.toString();
    }
    catch(JSONExeption e)
    {
        return new String("Exeption: " + e.getMessage());
    }
    catch(Exception e)
    {
        return new String("Exeption: " + e.getMessage());
    }
}

@Override
protected void onPostExecute(String result) {
    pDialog.dismiss();
    super.onPostExecute(result);
}
}

MainActivity.java

package com.example.testphp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

String username;
String password;
EditText edtUsername;
EditText edtPassword;
EditText edtResult;
Button btnInsert;


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

    btnInsert = (Button) findViewById(R.id.btn_insert);
    edtPassword = (EditText) findViewById(R.id.edt_password);
    edtUsername = (EditText) findViewById(R.id.edt_username);
    edtResult = (EditText) findViewById(R.id.edt_result);

    btnInsert.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {

            username = edtUsername.getText().toString();
            password = edtPassword.getText().toString();
            new InsertClass(MainActivity.this, edtResult).execute(username,password);

        }
    });

}

    @Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

test.PHP

<?php

$con = mysqli_connect("localhost" , "root" , "","test");
if(mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_errno();
} 
$username = $_POST['username'];
$password = $_POST['password'];

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES '$username','$password')");
if($result)
{
$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = $username");
if($id_result)
{
$response = array("id" => $id_result);
echo json_encode($response);
}
}
mysqli_close($con);
?>

Any suggestion, would be appreciated ...

Answer 1

Far as I can see, you have 2 errors in your SQL.

This line is missing a bracket:

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES  '$username','$password')");
                                                                     ^ bracket

Which should read as:

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES ('$username','$password')");

This line is missing quotes for $username

$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = $username");

Which should read as:

$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = '$username'");

Add or die(mysqli_error($con)) to mysqli_query() to see the actual error.

You should also guard against SQL injection, change your POST variables to:

$username = stripslashes($_POST['username']);
$username = mysqli_real_escape_string($con, $_POST['username']);

$password = stripslashes($_POST['password']);
$password = mysqli_real_escape_string($con, $_POST['password']);

Look into mysqli with prepared statements , or PDO with prepared statements , they're much safer .

I won't be able to help you with the Android code, but see what Selvin mentioned in a comment:

"you are catching an exception and do nothing with it (do at least e.printStackTrace() to see it in Logcat) ... and i'm pretty sure that you are hurting UI with bad touch, UI doesn't like to be touched from not UI thread"