ADFA-3574 | Add drag and drop support for Git repository URLs (#1132)

* feat(dnd): implement core drag-and-drop architecture and Git URL support
Add reusable DragEventRouter and enable Git URL dropping for repository cloning.

* refactor: Use URIish to handle various Git URL formats

Author: jatezzz

app/src/main/java/com/itsaky/androidide/dnd/DragEventRouter.kt

@@ -0,0 +1,53 @@
+package com.itsaky.androidide.dnd
+
+import android.view.DragEvent
+import android.view.View
+
+/**
+ * A [View.OnDragListener] implementation that delegates the complex Android drag state machine
+ * into a clean [DropTargetCallback].
+ */
+class DragEventRouter(
+    private val callback: DropTargetCallback
+) : View.OnDragListener {
+    override fun onDrag(view: View, event: DragEvent): Boolean {
+        val canHandle = callback.canAcceptDrop(event)
+
+        return when (event.action) {
+            DragEvent.ACTION_DRAG_STARTED -> {
+                if (canHandle) callback.onDragStarted(view)
+                canHandle
+            }
+
+            DragEvent.ACTION_DRAG_ENTERED -> {
+                if (canHandle) callback.onDragEntered(view)
+                true
+            }
+
+            DragEvent.ACTION_DRAG_LOCATION -> {
+                canHandle
+            }
+
+            DragEvent.ACTION_DRAG_EXITED -> {
+                callback.onDragExited(view)
+                true
+            }
+
+            DragEvent.ACTION_DROP -> {
+                callback.onDragExited(view)
+                if (canHandle) {
+                    callback.onDrop(event)
+                } else {
+                    false
+                }
+            }
+
+            DragEvent.ACTION_DRAG_ENDED -> {
+                callback.onDragExited(view)
+                canHandle
+            }
+
+            else -> false
+        }
+    }
+}

app/src/main/java/com/itsaky/androidide/dnd/DropTargetCallback.kt

@@ -0,0 +1,35 @@
+package com.itsaky.androidide.dnd
+
+import android.view.DragEvent
+import android.view.View
+
+/**
+ * Callback interface for handling routed drag-and-drop events on a specific target view.
+ */
+interface DropTargetCallback {
+    /**
+     * Determines whether the current [event] contains data that this target can handle.
+     */
+    fun canAcceptDrop(event: DragEvent): Boolean
+
+    /**
+     * Called when a drag operation begins. Useful for applying initial visual cues.
+     */
+    fun onDragStarted(view: View) {}
+
+    /**
+     * Called when a valid dragged item enters the bounds of the target [view].
+     */
+    fun onDragEntered(view: View)
+
+    /**
+     * Called when a dragged item exits the target [view], or when the drag operation ends/is canceled.
+     */
+    fun onDragExited(view: View)
+
+    /**
+     * Called when the user successfully drops a valid item on the target.
+     * * @return True if the drop was successfully consumed and handled.
+     */
+    fun onDrop(event: DragEvent): Boolean
+}

app/src/main/java/com/itsaky/androidide/dnd/GitUrlDropExtensions.kt

@@ -0,0 +1,28 @@
+package com.itsaky.androidide.dnd
+
+import android.view.View
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.LifecycleOwner
+
+
+fun Fragment.handleGitUrlDrop(
+    targetView: View = requireView(),
+    shouldAcceptDrop: () -> Boolean = { isVisible },
+    onDropped: (String) -> Unit
+) {
+    val dropTarget = GitUrlDropTarget(
+        context = requireContext(),
+        rootView = targetView,
+        shouldAcceptDrop = shouldAcceptDrop,
+        onRepositoryDropped = onDropped
+    )
+
+    dropTarget.attach()
+
+    viewLifecycleOwner.lifecycle.addObserver(object : DefaultLifecycleObserver {
+        override fun onDestroy(owner: LifecycleOwner) {
+            dropTarget.detach()
+        }
+    })
+}

app/src/main/java/com/itsaky/androidide/dnd/GitUrlDropTarget.kt

@@ -0,0 +1,107 @@
+package com.itsaky.androidide.dnd
+
+import android.content.ClipDescription
+import android.content.Context
+import android.view.DragEvent
+import android.view.View
+import androidx.core.view.ContentInfoCompat
+import androidx.core.view.ViewCompat
+import com.itsaky.androidide.git.core.parseGitRepositoryUrl
+import com.itsaky.androidide.utils.DropHighlighter
+
+internal class GitUrlDropTarget(
+    private val context: Context,
+    private val rootView: View,
+    private val shouldAcceptDrop: () -> Boolean = { true },
+    private val onRepositoryDropped: (String) -> Unit,
+) {
+
+    fun attach() {
+        ViewCompat.setOnReceiveContentListener(
+            rootView,
+            supportedDropMimeTypes,
+        ) { _, payload -> tryConsumeRepositoryPayload(payload) }
+
+        bindRepositoryDropTarget(rootView)
+    }
+
+    fun detach() {
+        ViewCompat.setOnReceiveContentListener(rootView, null, null)
+        rootView.setOnDragListener(null)
+    }
+
+    /**
+     * Attempts to consume a dropped repository URL from the given [payload].
+     * Returns `null` on success to indicate consumption, or the original [payload] otherwise.
+     */
+    private fun tryConsumeRepositoryPayload(payload: ContentInfoCompat): ContentInfoCompat? {
+        if (!shouldAcceptDrop()) {
+            return payload
+        }
+
+        val repositoryUrl = extractRepositoryUrl(payload) ?: return payload
+
+        onRepositoryDropped(repositoryUrl)
+        return null
+    }
+
+    private fun bindRepositoryDropTarget(view: View) {
+        val dropCallback = object : DropTargetCallback {
+            override fun canAcceptDrop(event: DragEvent): Boolean {
+                return shouldAcceptDrop() && event.clipDescription.isSupportedDropPayload()
+            }
+
+            override fun onDragStarted(view: View) {
+                DropHighlighter.highlight(view, context)
+            }
+
+            override fun onDragEntered(view: View) {
+                DropHighlighter.highlight(view, context)
+            }
+
+            override fun onDragExited(view: View) {
+                DropHighlighter.clear(view)
+            }
+
+            override fun onDrop(event: DragEvent): Boolean {
+                val contentInfo = ContentInfoCompat.Builder(
+                    event.clipData,
+                    ContentInfoCompat.SOURCE_DRAG_AND_DROP,
+                ).build()
+
+                return ViewCompat.performReceiveContent(view, contentInfo) == null
+            }
+        }
+
+        view.setOnDragListener(DragEventRouter(dropCallback))
+    }
+
+    private fun extractRepositoryUrl(payload: ContentInfoCompat): String? {
+        val clip = payload.clip
+        for (index in 0 until clip.itemCount) {
+            val item = clip.getItemAt(index)
+            val text = item.uri?.toString() ?: item.coerceToText(context)?.toString()
+
+            if (text.isNullOrBlank()) continue
+
+            parseGitRepositoryUrl(text)?.let { return it }
+        }
+
+        return null
+    }
+
+    private fun ClipDescription?.isSupportedDropPayload(): Boolean {
+        if (this == null) {
+            return false
+        }
+
+        return supportedDropMimeTypes.any(::hasMimeType)
+    }
+
+    private companion object {
+        val supportedDropMimeTypes = arrayOf(
+            ClipDescription.MIMETYPE_TEXT_PLAIN,
+            ClipDescription.MIMETYPE_TEXT_URILIST,
+        )
+    }
+}

app/src/main/java/com/itsaky/androidide/fragments/CloneRepositoryFragment.kt

@@ -19,6 +19,7 @@ import com.itsaky.androidide.viewmodel.CloneRepositoryViewModel
 import com.itsaky.androidide.viewmodel.MainViewModel
 import com.itsaky.androidide.git.core.models.CloneRepoUiState
 import com.itsaky.androidide.R
+import com.itsaky.androidide.dnd.handleGitUrlDrop
 import com.itsaky.androidide.idetooltips.TooltipManager
 import com.itsaky.androidide.idetooltips.TooltipTag
 import com.itsaky.androidide.utils.forEachViewRecursively
@@ -44,7 +45,12 @@ class CloneRepositoryFragment : BaseFragment() {
         super.onViewCreated(view, savedInstanceState)
 
         setupUI()
+        observePendingCloneUrl()
         observeViewModel()
+        handleGitUrlDrop { url ->
+            binding?.repoUrl?.setText(url)
+            viewModel.onInputChanged(url, binding?.localPath?.text?.toString().orEmpty())
+        }
     }
 
     private fun setupUI() {
@@ -201,6 +207,20 @@ class CloneRepositoryFragment : BaseFragment() {
         }
     }
 
+    private fun observePendingCloneUrl() {
+        viewLifecycleOwner.lifecycleScope.launch {
+            viewLifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
+                mainViewModel.cloneRepositoryEvent.collect { url ->
+                    val trimmedUrl = url.trim()
+                    if (trimmedUrl.isNotBlank()) {
+                        binding?.repoUrl?.setText(trimmedUrl)
+                        viewModel.onInputChanged(trimmedUrl, binding?.localPath?.text?.toString().orEmpty())
+                    }
+                }
+            }
+        }
+    }
+
     private fun MaterialButton.refreshStatus(isForRetry: Boolean) {
         setIconResource(if (isForRetry) R.drawable.ic_refresh else 0)
 

app/src/main/java/com/itsaky/androidide/fragments/MainFragment.kt

@@ -5,7 +5,6 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
-import org.koin.androidx.viewmodel.ext.android.activityViewModel
 import com.itsaky.androidide.R
 import com.itsaky.androidide.activities.editor.HelpActivity
 import com.itsaky.androidide.adapters.MainActionsListAdapter
@@ -14,11 +13,14 @@ import com.itsaky.androidide.actions.ActionItem
 import com.itsaky.androidide.actions.ActionsRegistry
 import com.itsaky.androidide.actions.internal.DefaultActionsRegistry
 import com.itsaky.androidide.databinding.FragmentMainBinding
+import com.itsaky.androidide.dnd.handleGitUrlDrop
 import com.itsaky.androidide.idetooltips.TooltipManager
 import com.itsaky.androidide.idetooltips.TooltipTag.MAIN_GET_STARTED
 import com.itsaky.androidide.viewmodel.MainViewModel
 import org.adfa.constants.CONTENT_KEY
 import org.adfa.constants.CONTENT_TITLE_KEY
+import org.appdevforall.codeonthego.layouteditor.managers.ProjectManager
+import org.koin.androidx.viewmodel.ext.android.activityViewModel
 
 class MainFragment : BaseFragment() {
 	private val viewModel by activityViewModel<MainViewModel>()
@@ -81,6 +83,15 @@ class MainFragment : BaseFragment() {
 			true
 		}
 		binding!!.greetingText.setOnClickListener { ifAttached { openQuickstartPageAction() } }
+
+		handleGitUrlDrop(
+			shouldAcceptDrop = {
+				isVisible &&
+				viewModel.currentScreen.value == MainViewModel.SCREEN_MAIN &&
+				ProjectManager.instance.openedProject == null
+			},
+			onDropped = viewModel::requestCloneRepository
+		)
 	}
 
 	private fun openQuickstartPageAction() {

app/src/main/java/com/itsaky/androidide/utils/DropHighlighter.kt

@@ -0,0 +1,35 @@
+package com.itsaky.androidide.utils
+
+import android.content.Context
+import android.graphics.drawable.Drawable
+import android.view.View
+import androidx.core.content.ContextCompat
+import com.itsaky.androidide.R
+import androidx.core.graphics.drawable.toDrawable
+
+object DropHighlighter {
+    /**
+     * Applies a highlight foreground to the [view] to indicate an active drop target,
+     * saving its original foreground state safely.
+     */
+    fun highlight(view: View, context: Context) {
+        if (view.getTag(R.id.filetree_drop_target_tag) == null) {
+            view.setTag(R.id.filetree_drop_target_tag, view.foreground ?: "NULL_FG")
+        }
+
+        val baseColor = ContextCompat.getColor(context, R.color.teal_200)
+        val highlightColor = (baseColor and 0x00FFFFFF) or (64 shl 24)
+
+        view.foreground = highlightColor.toDrawable()
+    }
+
+    /**
+     * Restores the original foreground of the [view] and clears the drop target highlight.
+     */
+    fun clear(view: View) {
+        val savedFg = view.getTag(R.id.filetree_drop_target_tag) ?: return
+
+        view.foreground = if (savedFg == "NULL_FG") null else savedFg as? Drawable
+        view.setTag(R.id.filetree_drop_target_tag, null)
+    }
+}