package com.mycompany.myapp;
import android.content.*;
import android.widget.*;
import android.app.*;
import java.security.*;
import android.content.SharedPreferences;
import android.content.Context;

public class MainLogin implements Logger
{
    private String userName = null;
    private String password = null;
    private DBHelper db = null;
    private Context context;
    private SharedPreferences preferences;
    private SharedPreferences loggedInPreferences;

    public void MainLoginSetter(String userName , String password , Context context){
        this.userName = userName;
        this.password = password;
        this.context = context;
    }

    @Override
    public Boolean Login(){
        db = new DBHelper(context);
        preferences = context.getSharedPreferences(SignUpAndRegistrationActivity.SPREFERENCES, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = preferences.edit();


 if(this.userName.toString().equals(db.getUser(this.userName)) && this.password.toString().equals(db.getPassword(this.password))){
            editor.putBoolean("loggedIn", true);
        editor.putString("User",db.getRowUsers("UserName",this.userName));
            editor.commit();
            return true;
            }
        return false;
     }

    @Override
    public Boolean Logout(){
    preferences =  context.getSharedPreferences(SignUpAndRegistrationActivity.SPREFERENCES , Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = preferences.edit();
        editor.clear();
        editor.commit();
        editor.putBoolean("loggedIn", false);
        return true;
    }

 }

package com.mycompany.myapp;

import android.app.*;
import android.os.*;
import android.widget.*;
import android.content.*;
import android.view.View.*;
import android.view.*;
import java.security.*;
import java.nio.charset.*;
import android.util.*;

public class MainActivity extends Activity
{
    private MainLogin mainLogin;
    private FacebookLogin fbLogin;
    private GoogleLogin googleLogin;
    private Intent intent;
    private Boolean LoggedIn = null;
    private Boolean Failure = false;
    private Integer loginAttempts = 3;

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

        final EditText userName = (EditText) findViewById(R.id.credential_one);
        final EditText password = (EditText) findViewById(R.id.credential_two);
        final Button loginButton = (Button) findViewById(R.id.loginButton);

         loginButton.setOnClickListener(new OnClickListener(){
             public void onClick(View view){
                 LoggedIn = true;

if(userName.getText().toString().isEmpty() || password.getText().toString().isEmpty() && userName.getText().toString() == null  && password.getText().toString() == null){
                    Toast.makeText(MainActivity.this, "Please fill in credentials", Toast.LENGTH_LONG).show();
                    intent = new Intent(MainActivity.this , Home.class);
                } else {

                     mainLogin = new MainLogin();

 mainLogin.MainLoginSetter(userName.getText().toString(), password.getText().toString(), MainActivity.this);
                    if(mainLogin.Login() == LoggedIn){
                         intent = new Intent(MainActivity.this , Home.class);
                        startActivity(intent);
                        finish();
                    } else if(mainLogin.Login() == Failure){
                        loginAttempts--;
                    }
                }

                if(loginAttempts == 0){
                    Toast.makeText(MainActivity.this, "Unsuccessful Login", Toast.LENGTH_LONG).show();
                }
                }
        });

        final TextView signup = (TextView) findViewById(R.id.signupTextView);

        signup.setOnClickListener(new OnClickListener(){
             public void onClick(View view){
                intent = new Intent(MainActivity.this, SignUpAndRegistrationActivity.class);
                startActivity(intent);
            }
        });

    }

    @Override
    protected void onResume(){
        SharedPreferences preferences = this.getSharedPreferences(SignUpAndRegistrationActivity.SPREFERENCES , Context.MODE_PRIVATE);
        boolean signedIn = preferences.getBoolean("loggedIn", false);
        if(signedIn == true){
            Intent intent = new Intent(MainActivity.this, Home.class);
            startActivity(intent);
            finish();
         } else if(signedIn == false){
            super.onResume();
        }
        super.onResume();
        }

    @Override
    public void onBackPressed(){
        finish();
        super.onBackPressed();
    }


}