shalty login

package com.example.shalty.login;

import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class Reg extends AppCompatActivity {

    EditText userName;
    EditText password;
    EditText verPassword;
    SharedPreferences prefs;

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


        userName = (EditText)findViewById(R.id.userNameReg);
        password = (EditText)findViewById(R.id.passReg);
        verPassword = (EditText)findViewById(R.id.passVal);
        prefs=getApplicationContext().getSharedPreferences("myPref",MODE_PRIVATE);

    }
    public void SignUp(View v)
    {
        if(password.getText().toString().equals(verPassword.getText().toString()))
        {

                if(prefs.getString(userName.getText().toString(), "notExist").equals("notExist")) {
                    saveData();
                    Intent logIn = new Intent(this, Login.class);
                    this.startActivity(logIn);
                }
                else
                {
                    Toast.makeText(this, "Username already exists Please choose another ", Toast.LENGTH_LONG).show();
                    this.startActivity(new Intent(this,Reg.class));
                }

        }else {
            Toast.makeText(this, "Passwords do not match, please try again", Toast.LENGTH_LONG).show();
            this.startActivity(new Intent(this,Reg.class));
        }
    }
    private void saveData()
    {
        SharedPreferences.Editor editor=prefs.edit();
        editor.putString(userName.getText().toString(), password.getText().toString());
        editor.commit();
       // Toast.makeText(this, "============saveData==============", Toast.LENGTH_LONG).show();

    }
    public void Cancel(View v)
    {
        Intent login = new Intent(this, Login.class);
        this.startActivity(login);

    }



}
=====================================================================================

package com.example.shalty.login;

import android.content.Intent;
import android.content.SharedPreferences;
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.TextView;
import android.widget.Toast;

public class Login extends AppCompatActivity {

    private EditText userName;
    private EditText password;
    SharedPreferences prefs;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        prefs=getApplicationContext().getSharedPreferences("myPref",MODE_PRIVATE);
        userName =(EditText)findViewById(R.id.userName);
        password =(EditText)findViewById(R.id.pass);
        if(prefs.getString(userName.getText().toString(),"logdIn").toString().equals("logdIn"))
        {
            Intent HomePage = new Intent(this,HomePage.class);
            HomePage.putExtra("Name",prefs.getString(userName.getText().toString(), "logdIn"));
        }

    }

   public void signUp(View v)
    {
        Intent signUp = new Intent(this,Reg.class);
        this.startActivity(signUp);
    }
    public void logIn(View v)
    {
        if (!prefs.getString(userName.getText().toString(), "notExist").toString().equals("notExist"))
        {

            if (!prefs.getString(password.getText().toString(), "notExist").toString().equals("notExist"))
            {
                Intent homPage = new Intent(this, HomePage.class);
                homPage.putExtra("name",userName.getText().toString());;
                SharedPreferences.Editor editor=prefs.edit();
                editor.putString(userName.getText().toString(), "logdIn");
                startActivity(homPage);
            } else
                Toast.makeText(this, "The username or password are incorrect", Toast.LENGTH_LONG).show();
        }
        else
            Toast.makeText(this, "Username does not exist please signup ", Toast.LENGTH_LONG).show();
    }
}
===================================================================================================

package com.example.shalty.login;

import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class HomePage extends AppCompatActivity {

    TextView hom ;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home_page);
        hom = (TextView)findViewById(R.id.helow);
        hom.setText("Hello " + getIntent().getStringExtra("name"));


    }
    public void logUot(View v)
    {
        SharedPreferences prefs=getApplicationContext().getSharedPreferences("myPref",MODE_PRIVATE);
        SharedPreferences.Editor editor=prefs.edit();
        editor.remove("logdIn");
        editor.commit();
        Intent login = new Intent(this,Login.class);
        this.startActivity(login);

    }
}