LoginViewExample_step1_MainActivity.java

package it.enricocandino.loginviewexample;

import android.content.Context;
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;

public class MainActivity extends AppCompatActivity {

    private Context mContext = MainActivity.this;

    private EditText usernameEditText;
    private EditText passwordEditText;
    private Button loginButton;

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

        usernameEditText = (EditText) findViewById(R.id.username_edittext);
        passwordEditText = (EditText) findViewById(R.id.password_edittext);
        loginButton = (Button) findViewById(R.id.login_button);

        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = usernameEditText.getText().toString();
                String password = passwordEditText.getText().toString();

                if (!username.equals("") && !password.equals("")) {
                    Toast.makeText(mContext, "Logging in", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(mContext, "Missing username or password", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}