Add launcher screen with two big app buttons

app/src/main/java/com/example/ichwillheim/MainActivity.kt

@@ -0,0 +1,108 @@
+package com.example.ichwillheim
+
+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.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.example.ichwillheim.ui.theme.IchWillHeimTheme
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContent {
+            IchWillHeimTheme {
+                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
+                    LauncherScreen(modifier = Modifier.padding(innerPadding))
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun LauncherScreen(modifier: Modifier = Modifier) {
+    val context = LocalContext.current
+    val apps = listOf(
+        AppEntry(
+            label = "Phone",
+            packageName = "com.android.dialer"
+        ),
+        AppEntry(
+            label = "Messages",
+            packageName = "com.google.android.apps.messaging"
+        )
+    )
+
+    Column(
+        modifier = modifier
+            .fillMaxSize()
+            .padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally
+    ) {
+        Text(
+            text = "Hallo Renate!",
+            style = MaterialTheme.typography.headlineSmall
+        )
+        Spacer(modifier = Modifier.height(24.dp))
+        apps.forEach { app ->
+            Button(
+                onClick = { launchApp(context, app) },
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .height(96.dp)
+            ) {
+                Text(text = app.label, fontSize = 24.sp)
+            }
+            Spacer(modifier = Modifier.height(16.dp))
+        }
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+fun LauncherPreview() {
+    IchWillHeimTheme {
+        LauncherScreen()
+    }
+}
+
+@Immutable
+data class AppEntry(
+    val label: String,
+    val packageName: String
+)
+
+private fun launchApp(context: android.content.Context, app: AppEntry) {
+    val intent = context.packageManager.getLaunchIntentForPackage(app.packageName)
+    if (intent != null) {
+        context.startActivity(intent)
+    } else {
+        Toast.makeText(
+            context,
+            "App not found: ${app.label}",
+            Toast.LENGTH_SHORT
+        ).show()
+    }
+}