Create an application with first activity with an edit text and send button. On click of send button, make use of implicit intent that uses a SEND ACTION and let user select app from chooser and navigate to that application.

/*Create an application with first activity with an edit text and send button. On click of send button, make use of implicit intent that uses a SEND ACTION and let user select app from chooser and navigate to that application.*/

File Name: activity_main.xml

<RelativeLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin"

    tools:context=".MainActivity">

    <EditText

        android:id="@+id/editText1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentRight="true"

        android:layout_alignParentTop="true"

        android:layout_marginRight="22dp"

        android:layout_marginTop="16dp"

         />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText1"

        android:layout_below="@+id/editText1"

        android:layout_marginTop="20dp"

        >

        <requestFocus />

    </EditText>

    <EditText

        android:id="@+id/editText3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText2"

        android:layout_below="@+id/editText2"

        android:layout_marginTop="30dp"

        android:inputType="textMultiLine" />

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/editText1"

        android:layout_alignBottom="@+id/editText1"

        android:layout_alignParentLeft="true"

        android:text="To:" />

    <TextView

        android:id="@+id/textView2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/editText2"

        android:layout_alignBottom="@+id/editText2"

        android:layout_alignParentLeft="true"

        android:text="Subject:" />

    <TextView

        android:id="@+id/textView3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/editText3"

        android:layout_alignBottom="@+id/editText3"

        android:layout_alignParentLeft="true"

        android:text="Message:" />

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText3"

        android:layout_below="@+id/editText3"

        android:layout_marginLeft="70dp"

        android:layout_marginTop="25dp"

        android:text="Send" />

</RelativeLayout>    

File Name: MainActivity.java

package com.ducskecode.lifecycle;

import android.app.Activity;

import android.content.Intent;

import android.net.Uri;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends Activity {

    EditText editTextTo,editTextSubject,editTextMessage;

    Button send;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        editTextTo=(EditText)findViewById(R.id.editText1);

        editTextSubject=(EditText)findViewById(R.id.editText2);

        editTextMessage=(EditText)findViewById(R.id.editText3);

        send=(Button)findViewById(R.id.button1);

        send.setOnClickListener(new View.OnClickListener(){

            @Override

            public void onClick(View arg0) {

                String to=editTextTo.getText().toString();

                String subject=editTextSubject.getText().toString();

                String message=editTextMessage.getText().toString();

                Intent email = new Intent(Intent.ACTION_SEND);

                email.putExtra(Intent.EXTRA_EMAIL, new String[]{ to});

                email.putExtra(Intent.EXTRA_SUBJECT, subject);

                email.putExtra(Intent.EXTRA_TEXT, message);

                email.setType("message/rfc822");

                startActivity(Intent.createChooser(email, "Choose an Email client :"));

            }

        });

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_main, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

}

output: