RxLoginExample

Events.java

package com.example.vrajeevan.rxloginexample.rx;

import android.text.Editable;
import android.text.TextWatcher;
import android.view.MotionEvent;
import android.widget.Button;
import android.widget.TextView;

import rx.Observable;
import rx.subjects.BehaviorSubject;
import rx.subjects.PublishSubject;

/**
 * Created by vrajeevan on 10/9/14.
 */
public class Events {
    /*
        * Creates a subject that emits events for the current text and each text change event
        */
    public static Observable<String> observableFromTextView(TextView view) {
        String currentText = String.valueOf(view.getText());
        final BehaviorSubject<String> subject = BehaviorSubject.create(currentText);
        view.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
            }

            @Override
            public void afterTextChanged(Editable editable) {
                subject.onNext(editable.toString());
            }
        });
        return subject;
    }

    public static Observable<Boolean> observableFromButtonClick(Button button) {
        final PublishSubject<Boolean> subject = PublishSubject.create();
        button.setOnClickListener(v -> subject.onNext(true));
        return subject;
    }

    public static Observable<Boolean> observableFromButtonDown(Button button) {
        final PublishSubject<Boolean> subject = PublishSubject.create();
        button.setOnTouchListener((v, event) -> {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    subject.onNext(true);
                    break;
                case MotionEvent.ACTION_UP:
                    subject.onNext(false);
                    break;
            }
            return false;
        });

        return subject;
    }
}

LoginActivity.java

package com.example.vrajeevan.rxloginexample;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;

import com.example.vrajeevan.rxloginexample.rx.Events;

import butterknife.ButterKnife;
import butterknife.InjectView;
import rx.Observable;


/**
 * A login screen that offers login via email/password.
 */
public class LoginActivity extends Activity {

    @InjectView(R.id.email) AutoCompleteTextView mEmail;
    @InjectView(R.id.password) EditText mPassword;
    @InjectView(R.id.email_sign_in_button) Button mEmailSignInButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        ButterKnife.inject(this);

        // Set up the login form.
        mEmailSignInButton.setBackgroundColor(getResources().getColor(android.R.color.holo_red_dark));

        Observable.combineLatest(Events.observableFromTextView(mEmail),
                                 Events.observableFromTextView(mPassword),
                                 (emailText, passwordText) -> !TextUtils.isEmpty(emailText) && !TextUtils.isEmpty(passwordText))
                  .map(fieldsFilled -> getResources().getColor(fieldsFilled
                                                               ? android.R.color.holo_green_light
                                                               : android.R.color.holo_red_dark))
                  .subscribe(color -> mEmailSignInButton.setBackgroundColor(color));

        Events.observableFromButtonDown(mEmailSignInButton)
                .map(isDown -> isDown ? "Down" : "Up")
                .subscribe(s -> mEmailSignInButton.setText(s));
    }


}