xml + kotlin Combination

app\manifests\AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApplication"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:label="@string/app_name"
            android:theme="@style/Theme.MyApplication">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

<!--    <application-->
<!--        android:allowBackup="true"-->
<!--        android:icon="@mipmap/ic_launcher"-->
<!--        android:label="My Application"-->
<!--        android:theme="@style/Theme.MyApplication">-->
<!--        <activity-->
<!--            android:name=".Act1Demo"-->
<!--            android:label="Act1Demo"-->
<!--            android:exported="true">-->
<!--            <intent-filter>-->
<!--                <action android:name="android.intent.action.MAIN" />-->
<!--                <category android:name="android.intent.category.LAUNCHER" />-->
<!--            </intent-filter>-->
<!--        </activity>-->
<!--    </application>-->


</manifest>

app\kotlin+java\MainActivity.kt

package com.example.myapplication

import android.os.Bundle
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.*
import androidx.compose.material3.*
import androidx.compose.runtime.Composable
import androidx.compose.ui.AbsoluteAlignment
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.example.myapplication.ui.theme.MyApplicationTheme
import androidx.compose.ui.platform.LocalContext

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)


        enableEdgeToEdge()
        setContent {
            MyApplicationTheme {
                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
                    Column(
                        modifier = Modifier
                            .padding(innerPadding)
                            .fillMaxSize()
                            .padding(25.dp),
                        verticalArrangement = Arrangement.Center,
                        horizontalAlignment = Alignment.CenterHorizontally // Centering horizontally
                    ) {
                        Greeting(name = "Android")
                        Spacer(modifier = Modifier.height(16.dp))
                        ShowToastButton()
                        ShowToastButton01()
                    }
                }
            }
        }
    }
}

@Composable
fun Greeting(name: String, modifier: Modifier = Modifier) {
    Text(
        text = "Hello $name!",
        modifier = modifier
    )
}

@Composable
fun ShowToastButton() {
    val context = LocalContext.current
    Button(onClick = {
        Toast.makeText(context, "Button Android clicked!", Toast.LENGTH_SHORT).show()
    }) {
        Text("Show Toast")
    }
}

@Composable
fun ShowToastButton01() {
    val context = LocalContext.current
    Button(onClick = {
        Toast.makeText(context, "Button Java clicked!", Toast.LENGTH_SHORT).show()
    }) {
        Text("Show Toast")
    }
}


@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    MyApplicationTheme {
        Greeting("Android")
    }
}

Run Application  See Result On ADA

🔍 Key Differences