Question

Can any one please tell me where to find a simple tutorial that shows how to make an Android application that connects to a external MySQL database, and report back some data?

The tutorials I found on the Internet are not exact – they dont work or the code is not complete.

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import android.widget.Toast;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;

public class main extends Activity {
    /** Called when the activity is first created. */
    Button login;
    String name = "", pass = "";
    EditText username, password;
    TextView tv;
    byte[] data;
    HttpPost httppost;
    StringBuffer buffer;
    HttpResponse response;
    HttpClient httpclient;
    InputStream inputStream;
    SharedPreferences app_preferences;
    List<NameValuePair> nameValuePairs;
    CheckBox check;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        app_preferences = PreferenceManager.getDefaultSharedPreferences(this);
        username = (EditText) findViewById(R.id.username);
        password = (EditText) findViewById(R.id.password);
        login = (Button) findViewById(R.id.login);
        check = (CheckBox) findViewById(R.id.check);

        String Str_user = app_preferences.getString("username", "0");
        String Str_pass = app_preferences.getString("password", "0");
        String Str_check = app_preferences.getString("checked", "no");
        if (Str_check.equals("yes")) {
            username.setText(Str_user);
            password.setText(Str_pass);
            check.setChecked(true);
        }

        login.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                name = username.getText().toString();
                pass = password.getText().toString();
                String Str_check2 = app_preferences.getString("checked", "no");
                if (Str_check2.equals("yes")) {
                    SharedPreferences.Editor editor = app_preferences.edit();
                    editor.putString("username", name);
                    editor.putString("password", pass);
                    editor.commit();
                }
                if (name.equals("") || pass.equals("")) {
                    Toast.makeText(main.this, "Blank Field..Please Enter",
                            Toast.LENGTH_LONG).show();
                } else {
                    try {
                        httpclient = new DefaultHttpClient();
                        httppost = new HttpPost(
                                "http://www.****.com/android/check.php");

                        // Add your data
                        nameValuePairs = new ArrayList<NameValuePair>(2);
                        nameValuePairs.add(new BasicNameValuePair("UserEmail",
                                name.trim()));
                        nameValuePairs.add(new BasicNameValuePair("Password",
                                pass.trim()));
                        httppost.setEntity(new UrlEncodedFormEntity(
                                nameValuePairs));

                        // Execute HTTP Post Request
                        response = httpclient.execute(httppost);
                        inputStream = response.getEntity().getContent();

                        data = new byte[256];

                        buffer = new StringBuffer();
                        int len = 0;
                        while (-1 != (len = inputStream.read(data))) {
                            buffer.append(new String(data, 0, len));
                        }

                        inputStream.close();
                    } catch (Exception e) {
                        Toast.makeText(main.this, "error" + e.toString(),
                                Toast.LENGTH_LONG).show();
                    }

                    if (buffer.charAt(0) == 'Y') {
                        Toast.makeText(main.this, "login successfull",
                                Toast.LENGTH_LONG).show();
                    } else {
                        Toast.makeText(main.this,
                                "Invalid Username or password",
                                Toast.LENGTH_LONG).show();
                    }
                }
            }
        });
        check.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // Perform action on clicks, depending on whether it's now
                // checked
                SharedPreferences.Editor editor = app_preferences.edit();
                if (((CheckBox) v).isChecked()) {

                    editor.putString("checked", "yes");
                    editor.commit();
                } else {
                    editor.putString("checked", "no");
                    editor.commit();
                }
            }
        });
    }

    public void Move_to_next() {
        // startActivity(new Intent(this, zzz.class));
    }
}

Answer 1

I couldn’t easily find a fully described example. But heres where i would start.

1. Look at content providers for managing your app data and accessing it and storing it for local use. The link below gives an extensive explanation of how content providers work. Though you don’t have to use one.

http://www.satyakomatineni.com/akc/display?url=DisplayNoteIMPURL&reportId=2882&ownerUserId=satya

The android content provider example also shows this.

1. On your server at home look at providing a rest full service layer for your app to request the information from. Rather than perhaps trying to directly access the database iteself. Discussed to some extent here on what to do (not specifically how to do it) https://groups.google.com/forum/?fromgroups#!topic/android-developers/rzV9tYpQZ5Y%5B1-25%5D

Afraid i don’t have coded examples.