EventBus Demo

1) ChildActivity.java

package eventbusdemo.credencys.com.eventbusdemo;

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.widget.Button;
import android.widget.EditText;

import org.greenrobot.eventbus.EventBus;

public class ChildActivity extends AppCompatActivity implements View.OnClickListener {
    private EditText messageEditText;
    private Button triggerEventButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_child);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        messageEditText = (EditText) findViewById(R.id.activity_child_edt_message);
        triggerEventButton = (Button) findViewById(R.id.activity_child_btn_trigger);

        triggerEventButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.activity_child_btn_trigger:
                String message = messageEditText.getText().toString().trim();

                CustomMessageEvent event = new CustomMessageEvent();
                event.setCustomMsg(message);
                EventBus.getDefault().post(event);
                finish();
                break;
        }
    }
}

2)CustomMessageEvent  .java

package eventbusdemo.credencys.com.eventbusdemo;

/**

 * Created by manisha on 20/2/17.

 */

public class CustomMessageEvent  {

    public String customMsg;

    public String getCustomMsg() {

        return customMsg;

    }

    public void setCustomMsg(String customMsg) {

        this.customMsg = customMsg;

    }

}

3)MainActivity .java

package eventbusdemo.credencys.com.eventbusdemo;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import org.greenrobot.eventbus.EventBus;

import org.greenrobot.eventbus.Subscribe;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText resultsEditText;

    private Button launchButton;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        resultsEditText = (EditText)findViewById(R.id.activity_main_edt_result);

        launchButton = (Button)findViewById(R.id.activity_main_btn_launch);

        launchButton.setOnClickListener(this);

        EventBus.getDefault().register(this);

    }

    @Subscribe

    public void onEvent(CustomMessageEvent event){

        Log.e("","Event bus::"+event.getCustomMsg());

        resultsEditText.setText(event.getCustomMsg());

    }

    @Override

    public void onClick(View v) {

        switch (v.getId()){

            case R.id.activity_main_btn_launch:

                Intent intent = new Intent(MainActivity.this,ChildActivity.class);

                startActivity(intent);

                break;

        }

    }

}

Gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "eventbusdemo.credencys.com.eventbusdemo"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })

    compile 'com.android.support:appcompat-v7:25.1.0'
    compile 'org.greenrobot:eventbus:3.0.0'
    compile 'com.android.support:design:25.1.0'
    testCompile 'junit:junit:4.12'
}