package com.alilozano.chatbazinga;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.alilozano.chatbazinga.utils.BazingaPreferences;

public class MainActivity extends AppCompatActivity {
    private BazingaPreferences prefs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        prefs = new BazingaPreferences(this);
        String currentUser = prefs.getString(BazingaPreferences.USUARIO_LOGUEADO, null);
        if(currentUser == null){
            Intent intent = new Intent(this, LoginActivity.class);
            startActivity(intent);
        }
    }
}









































package com.alilozano.chatbazinga;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.alilozano.chatbazinga.utils.BazingaPreferences;

public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
    private BazingaPreferences prefs;
    private Button btnLogin;
    private EditText txtUsuario;
    private EditText txtPassword;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        prefs = new BazingaPreferences(this);
        btnLogin = findViewById(R.id.btnLogin);
        txtUsuario = findViewById(R.id.txtUsuario);
        txtPassword = findViewById(R.id.txtPassword);
        btnLogin.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if(txtUsuario.getText().toString().equals("admin")
                && txtPassword.getText().toString().equals("admin")){
            Intent intent = new Intent(this, MainActivity.class);
            startActivity(intent);
            prefs.setString(BazingaPreferences.USUARIO_LOGUEADO, "admin");
        }else{
            Toast.makeText(this,
                    "Usuario/Contraseña incorrecta", Toast.LENGTH_SHORT).show();
        }
    }
}


























package com.alilozano.chatbazinga.utils;

import android.content.Context;
import android.content.SharedPreferences;

public class BazingaPreferences {
    private SharedPreferences prefs;
    private static String PREFERENCES_NAME="BazingaPreferences";
    public static String USUARIO_LOGUEADO="USUARIO_LOGUEADO";
    public BazingaPreferences(Context ctx) {
        prefs = ctx.getSharedPreferences(PREFERENCES_NAME, Context.MODE_PRIVATE);
    }
    public String getString(String key, String default_){
        return prefs.getString(key, default_);
    }
    public void setString(String key, String value){
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(key, value);
        editor.apply();
    }
}