Login.java

package com.coba.aplikasiku;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Patterns;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.net.Uri;

import com.basgeekball.awesomevalidation.AwesomeValidation;
import com.basgeekball.awesomevalidation.ValidationStyle;

import java.io.BufferedWriter;
import java.io.OutputStream;
import java.io.OutputStreamWriter;


public class Login extends Activity {

    // CONNECTION_TIMEOUT and READ_TIMEOUT are in milliseconds

    public static final int CONNECTION_TIMEOUT=10000;
    public static final int READ_TIMEOUT=15000;
    private EditText etEmail;
    private EditText etPassword;
    private Button btnLogin;

    private AwesomeValidation awesomeValidation;

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

        // Get Reference to variables
        etEmail = (EditText) findViewById(R.id.et_email);
        etPassword = (EditText) findViewById(R.id.et_password);
        btnLogin = (Button) findViewById(R.id.btn_login);

        awesomeValidation = new AwesomeValidation(ValidationStyle.BASIC);

        //adding validation to edittexts
        awesomeValidation.addValidation(this, R.id.et_email, Patterns.EMAIL_ADDRESS, R.string.emailerror);
        awesomeValidation.addValidation(this, R.id.et_password, "^[A-Za-z\\s]{1,}[\\.]{0,1}[A-Za-z\\s]{0,}$", R.string.passworderror);

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (awesomeValidation.validate()) {

                    // Get text from email and passord field
                    final String email = etEmail.getText().toString();
                    final String password = etPassword.getText().toString();

                    // Initialize  AsyncLogin() class with email and password
                    new AsyncLogin().execute(email,password);
                }

            }
        });

    }

    private class AsyncLogin extends AsyncTask<String, String, String> {
        ProgressDialog pdLoading = new ProgressDialog(Login.this);
        HttpURLConnection conn;
        URL url = null;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            //this method will be running on UI thread
            pdLoading.setMessage("\tMohon Ditunggu ...");
            pdLoading.setCancelable(false);
            pdLoading.show();

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

                // Enter URL address where your php file resides
                url = new URL("http://alamathosting.com/code/login.php");

            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                return "exception";
            }
            try {
                // Setup HttpURLConnection class to send and receive data from php and mysql
                conn = (HttpURLConnection)url.openConnection();
                conn.setReadTimeout(READ_TIMEOUT);
                conn.setConnectTimeout(CONNECTION_TIMEOUT);
                conn.setRequestMethod("POST");

                // setDoInput and setDoOutput method depict handling of both send and receive
                conn.setDoInput(true);
                conn.setDoOutput(true);

                // Append parameters to URL
                Uri.Builder builder = new Uri.Builder()
                        .appendQueryParameter("username", params[0])
                        .appendQueryParameter("password", params[1]);
                String query = builder.build().getEncodedQuery();

                // Open connection for sending data
                OutputStream os = conn.getOutputStream();
                BufferedWriter writer = new BufferedWriter(
                        new OutputStreamWriter(os, "UTF-8"));
                writer.write(query);
                writer.flush();
                writer.close();
                os.close();
                conn.connect();

            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
                return "exception";
            }

            try {

                int response_code = conn.getResponseCode();

                // Check if successful connection made
                if (response_code == HttpURLConnection.HTTP_OK) {

                    // Read data sent from server
                    InputStream input = conn.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(input));
                    StringBuilder result = new StringBuilder();
                    String line;

                    while ((line = reader.readLine()) != null) {
                        result.append(line);
                    }

                    // Pass data to onPostExecute method
                    return(result.toString());

                }else{

                    return("unsuccessful");
                }

            } catch (IOException e) {
                e.printStackTrace();
                return "exception";
            } finally {
                conn.disconnect();
            }

        }

        @Override
        protected void onPostExecute(String result) {

            //this method will be running on UI thread
            pdLoading.dismiss();

            if(result.equalsIgnoreCase("true")){
                /* Here launching another activity when login successful. If you persist login state
                use sharedPreferences of Android. and logout button to clear sharedPreferences.
                 */

                Intent intent = new Intent(Login.this,MainActivity.class);
                startActivity(intent);
                Login.this.finish();

            }else if (result.equalsIgnoreCase("false")){

                // If username and password does not match display a error message
                Toast.makeText(Login.this, "Username dan Password tidak sesuai", Toast.LENGTH_LONG).show();

            } else if (result.equalsIgnoreCase("exception") || result.equalsIgnoreCase("unsuccessful")) {

                Toast.makeText(Login.this, "Terjadi Kesalahan. Periksa Koneksi Anda.", Toast.LENGTH_LONG).show();

            }
        }

    }


    public void onClickRegister(View theButton) {
        Intent register = new Intent(this, Register.class);
        startActivity(register);
    }

    public void onClickForgot(View theButton) {
        Intent forgot = new Intent(this, ForgotPass.class);
        startActivity(forgot);
    }

}