MainActivity.java

package com.example.jin.java1d;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    public static final String DEFAULT_MESSAGE = "Someone";

    EditText username, password;
    Button button_login;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        username = (EditText)findViewById(R.id.enterusername);
        password = (EditText)findViewById(R.id.enterpassword);
        button_login = (Button)findViewById(R.id.loginbutton);

        button_login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(username.getText().toString().equals("admin")){
                    if(password.getText().toString().equals("password")){
                        Intent intenttohome = new Intent(MainActivity.this, newtabbed.class);
                        String loginmessage = username.getText().toString();
                        intenttohome.putExtra(DEFAULT_MESSAGE, loginmessage);
                        startActivity(intenttohome);
                    } else {
                        Toast.makeText(MainActivity.this, "Invalid Login", Toast.LENGTH_LONG).show();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "Invalid Login", Toast.LENGTH_LONG).show();
                }
            }
        });
    }




    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}