Button Click Open Gmail app and send email android kotlin example

Output: 

Give the recipient email, and subject body, and click on the  send email button it will open your Gmail app and set data for sending the email

process:

1/Modify the activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:orientation="vertical"
    android:gravity="center"
    android:paddingHorizontal="8dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <EditText
        android:id="@+id/recipientEmail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Recipient Email"
        android:inputType="textEmailAddress"
        android:padding="12dp" />

    <EditText
        android:id="@+id/subject"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Subject"
        android:padding="12dp"
        android:layout_marginTop="8dp" />

    <EditText
        android:id="@+id/body"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Email Body"
        android:inputType="textMultiLine"
        android:minLines="5"
        android:maxLines="5"
        android:gravity="top"
        android:padding="12dp"
        android:layout_marginTop="8dp" />

    <Button
        android:id="@+id/btnSendEmail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Send Email"
        android:layout_marginTop="16dp" />
  </LinearLayout>

2 /Modify the MainActivity.kt

package com.zissofworks.openappandsendgmail

import android.content.Intent
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat

class MainActivity : AppCompatActivity() {
    private lateinit var recipientEmail: EditText
    private lateinit var subject: EditText
    private lateinit var body: EditText
    private lateinit var btnSendEmail: Button

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_main)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }

        recipientEmail = findViewById(R.id.recipientEmail)
        subject = findViewById(R.id.subject)
        body = findViewById(R.id.body)
        btnSendEmail = findViewById(R.id.btnSendEmail)

        btnSendEmail.setOnClickListener {
            val recipient = recipientEmail.text.toString().trim()
            val subject = subject.text.toString().trim()
            val body = body.text.toString().trim()

            if (recipient.isEmpty()) {
                recipientEmail.error = "Please provide recipient email"
            }
            else if(subject.isEmpty()){
                recipientEmail.error = "Please provide subject"
            }
            else if(body.isEmpty()){
                recipientEmail.error = "Please provide body"
            }
            else sendEmail(recipient, subject, body)
        }
    }

    private fun sendEmail(recipient: String, subject: String, body: String) {
        val intent = Intent(Intent.ACTION_SEND).apply {
            putExtra(Intent.EXTRA_EMAIL, arrayOf(recipient))
            putExtra(Intent.EXTRA_SUBJECT, subject as CharSequence)
            putExtra(Intent.EXTRA_TEXT, body)
            type = "message/rfc822"
            setPackage("com.google.android.gm")

        }
        startActivity(Intent.createChooser(intent, "Choose email client:"))
    }
}