Fix Drag&Drop code to also support external apps (#546)

* Fix code to also support external apps

* Sort chronologically the snippets

* Move the Activity to be used without the nullability check

---------

Co-authored-by: Rob Orgiu <[email protected]>

Author: tiwiz

compose/snippets/src/main/java/com/example/compose/snippets/draganddrop/DragAndDropSnippets.kt

@@ -20,6 +20,7 @@ import android.content.ClipData
 import android.content.ClipDescription
 import android.os.Build
 import android.view.View
+import androidx.activity.compose.LocalActivity
 import androidx.annotation.RequiresApi
 import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.draganddrop.dragAndDropSource
@@ -31,6 +32,7 @@ import androidx.compose.ui.draganddrop.DragAndDropEvent
 import androidx.compose.ui.draganddrop.DragAndDropTarget
 import androidx.compose.ui.draganddrop.DragAndDropTransferData
 import androidx.compose.ui.draganddrop.mimeTypes
+import androidx.compose.ui.draganddrop.toAndroidDragEvent
 
 @RequiresApi(Build.VERSION_CODES.N)
 @OptIn(ExperimentalFoundationApi::class)
@@ -71,6 +73,22 @@ private fun DragAndDropSnippet() {
     }
     // [END android_compose_drag_and_drop_4]
 
+    LocalActivity.current?.let { activity ->
+        // [START android_compose_drag_and_drop_7]
+        val externalAppCallback = remember {
+            object : DragAndDropTarget {
+                override fun onDrop(event: DragAndDropEvent): Boolean {
+                    val permission =
+                        activity.requestDragAndDropPermissions(event.toAndroidDragEvent())
+                    // Parse received data
+                    permission?.release()
+                    return true
+                }
+            }
+        }
+        // [END android_compose_drag_and_drop_7]
+    }
+
     // [START android_compose_drag_and_drop_5]
     Modifier.dragAndDropTarget(
         shouldStartDragAndDrop = { event ->