App templates: change code

templates/desktop-template/src/main/kotlin/main.kt

@@ -1,6 +1,20 @@
 import androidx.compose.desktop.Window
 import androidx.compose.foundation.Text
+import androidx.compose.material.Button
+import androidx.compose.material.MaterialTheme
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 
 fun main() = Window {
-    Text("Hello, World!")
+    var text by remember { mutableStateOf("Hello, World!") }
+
+    MaterialTheme {
+        Button(onClick = {
+            text = "Hello, Desktop!"
+        }) {
+            Text(text)
+        }
+    }
 }

templates/multiplatform-template/common/src/androidMain/kotlin/AndroidApp.kt

@@ -0,0 +1 @@
+actual fun getPlatformName(): String = "Android"

templates/multiplatform-template/common/src/commonMain/kotlin/App.kt

@@ -1,7 +1,19 @@
 import androidx.compose.foundation.Text
-import androidx.compose.runtime.Composable
+import androidx.compose.material.Button
+import androidx.compose.material.MaterialTheme
+import androidx.compose.runtime.*
 
 @Composable
 fun App() {
-    Text("Hello, World!")
+    var text by remember { mutableStateOf("Hello, World!") }
+
+    MaterialTheme {
+        Button(onClick = {
+            text = "Hello, ${getPlatformName()}"
+        }) {
+            Text(text)
+        }
+    }
 }
+
+expect fun getPlatformName(): String

templates/multiplatform-template/common/src/desktopMain/kotlin/DesktopApp.kt

@@ -0,0 +1 @@
+actual fun getPlatformName(): String = "Desktop"