How to Compose Gmail on Button Click in Android Using Java and Kotlin

<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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/composeEmailButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Compose Email"
        android:layout_centerInParent="true"/>
</RelativeLayout>

package com.example.composeemail;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

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

        Button composeEmailButton = findViewById(R.id.composeEmailButton);
        composeEmailButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                composeEmail(new String[]{"recipient@example.com"}, "Subject", "Email body text");
            }
        });
    }

    public void composeEmail(String[] addresses, String subject, String body) {
        Intent intent = new Intent(Intent.ACTION_SENDTO);
        intent.setData(Uri.parse("mailto:")); // only email apps should handle this
        intent.putExtra(Intent.EXTRA_EMAIL, addresses);
        intent.putExtra(Intent.EXTRA_SUBJECT, subject);
        intent.putExtra(Intent.EXTRA_TEXT, body);
        if (intent.resolveActivity(getPackageManager()) != null) {
            startActivity(intent);
        }
    }
}

4. Implementing the Button Click in Kotlin

Open MainActivity.kt and implement the button click event to compose an email.

package com.example.composeemail

import android.content.Intent
import android.net.Uri
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        composeEmailButton.setOnClickListener {
            composeEmail(arrayOf("recipient@example.com"), "Subject", "Email body text")
        }
    }

    private fun composeEmail(addresses: Array<String>, subject: String, body: String) {
        val intent = Intent(Intent.ACTION_SENDTO).apply {
            data = Uri.parse("mailto:") // only email apps should handle this
            putExtra(Intent.EXTRA_EMAIL, addresses)
            putExtra(Intent.EXTRA_SUBJECT, subject)
            putExtra(Intent.EXTRA_TEXT, body)
        }
        if (intent.resolveActivity(packageManager) != null) {
            startActivity(intent)
        }
    }
}

5. Testing the Application

• Run the application on an Android device or emulator.
• Click the “Compose Email” button.
• Verify that the email composition screen appears with the recipient, subject, and body pre-filled.

Conclusion