feat: add undo redo actions in UI Designer

app/src/main/java/com/itsaky/androidide/EditorActivity.java

@@ -261,8 +261,7 @@ public class EditorActivity extends IDEActivity
       data.put(File.class, currentEditor.getEditor().getFile());
     }
 
-    ActionsRegistry.getInstance()
-        .fillMenu(data, com.itsaky.androidide.actions.ActionItem.Location.EDITOR_TOOLBAR, menu);
+    ActionsRegistry.getInstance().fillMenu(data, ActionItem.Location.EDITOR_TOOLBAR, menu);
   }
 
   @Nullable

app/src/main/java/com/itsaky/androidide/actions/EditorActivityAction.kt

@@ -33,7 +33,7 @@ abstract class EditorActivityAction : ActionItem {
   override var requiresUIThread: Boolean = false
 
   override fun prepare(data: ActionData) {
-    if (!hasRequiredData(data, Context::class.java)) {
+    if (!data.hasRequiredData(Context::class.java)) {
       markInvisible()
     }
   }

app/src/main/java/com/itsaky/androidide/actions/text/UndoAction.kt

@@ -24,11 +24,11 @@ import com.itsaky.androidide.actions.ActionData
 import com.itsaky.androidide.actions.EditorRelatedAction
 
 /** @author Akash Yadav */
-class UndoAction() : EditorRelatedAction() {
+class UndoAction(context: Context) : EditorRelatedAction() {
 
   override val id: String = "editor_undo"
 
-  constructor(context: Context) : this() {
+  init {
     label = context.getString(R.string.undo)
     icon = ContextCompat.getDrawable(context, R.drawable.ic_undo)
   }

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/UIDesignerActivity.kt

@@ -17,15 +17,22 @@
 
 package com.itsaky.androidide.uidesigner
 
+import android.annotation.SuppressLint
+import android.content.Context
 import android.os.Bundle
+import android.view.Menu
 import android.view.View
 import androidx.activity.viewModels
 import androidx.appcompat.app.ActionBarDrawerToggle
+import androidx.appcompat.view.menu.MenuBuilder
 import androidx.core.view.GravityCompat
-import com.google.android.material.bottomsheet.BottomSheetBehavior
-import com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_EXPANDED
-import com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_HIDDEN
+import androidx.fragment.app.Fragment
+import com.itsaky.androidide.actions.ActionData
+import com.itsaky.androidide.actions.ActionItem.Location.UI_DESIGNER_TOOLBAR
+import com.itsaky.androidide.actions.ActionsRegistry
 import com.itsaky.androidide.app.BaseIDEActivity
+import com.itsaky.androidide.uidesigner.actions.clearUiDesignerActions
+import com.itsaky.androidide.uidesigner.actions.registerUiDesignerActions
 import com.itsaky.androidide.uidesigner.databinding.ActivityUiDesignerBinding
 import com.itsaky.androidide.uidesigner.fragments.DesignerWorkspaceFragment
 import com.itsaky.androidide.uidesigner.viewmodel.WorkspaceViewModel
@@ -83,10 +90,45 @@ class UIDesignerActivity : BaseIDEActivity() {
         binding!!.root.closeDrawer(GravityCompat.START)
       }
     }
+  
+    registerUiDesignerActions(this)
+  }
+  
+  override fun onResume() {
+    super.onResume()
+    registerUiDesignerActions(this)
+  }
+  
+  override fun onPause() {
+    super.onPause()
+    clearUiDesignerActions()
   }
 
   override fun onDestroy() {
     super.onDestroy()
     binding = null
   }
+  
+  override fun onPrepareOptionsMenu(menu: Menu): Boolean {
+    ensureToolbarMenu(menu)
+    return true
+  }
+  
+  @SuppressLint("RestrictedApi")
+  override fun onCreateOptionsMenu(menu: Menu): Boolean {
+    if (menu is MenuBuilder) {
+      menu.setOptionalIconsVisible(true)
+    }
+    return true
+  }
+  
+  private fun ensureToolbarMenu(menu: Menu) {
+    menu.clear()
+    
+    val data = ActionData()
+    data.put(Context::class.java, this)
+    data.put(Fragment::class.java, binding!!.workspace.getFragment())
+    
+    ActionsRegistry.getInstance().fillMenu(data, UI_DESIGNER_TOOLBAR, menu)
+  }
 }

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/actions/RedoAction.kt

@@ -0,0 +1,49 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.actions
+
+import android.content.Context
+import androidx.core.content.ContextCompat
+import com.itsaky.androidide.actions.ActionData
+import com.itsaky.androidide.uidesigner.R
+
+/**
+ * Redo action for UI Designer.
+ *
+ * @author Akash Yadav
+ */
+class RedoAction(context: Context) : UiDesignerAction() {
+  
+  override val id: String = "ide.uidesigner.redo"
+  
+  init {
+    label = context.getString(R.string.redo)
+    icon = ContextCompat.getDrawable(context, R.drawable.ic_redo)
+  }
+  
+  override fun prepare(data: ActionData) {
+    visible = true
+    enabled = data.requireWorkspace().undoManager.canRedo()
+  }
+  
+  override fun execAction(data: ActionData): Any {
+    data.requireWorkspace().undoManager.redo()
+    data.requireActivity().invalidateOptionsMenu()
+    return true
+  }
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/actions/UiDesignerAction.kt

@@ -0,0 +1,64 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.actions
+
+import android.content.Context
+import android.graphics.drawable.Drawable
+import androidx.fragment.app.Fragment
+import com.itsaky.androidide.actions.ActionData
+import com.itsaky.androidide.actions.ActionItem
+import com.itsaky.androidide.actions.ActionItem.Location
+import com.itsaky.androidide.actions.ActionItem.Location.UI_DESIGNER_TOOLBAR
+import com.itsaky.androidide.actions.hasRequiredData
+import com.itsaky.androidide.actions.markInvisible
+import com.itsaky.androidide.uidesigner.UIDesignerActivity
+import com.itsaky.androidide.uidesigner.fragments.DesignerWorkspaceFragment
+
+/**
+ * Base class for actions that are shown in the UI Designer activity.
+ *
+ * @author Akash Yadav
+ */
+abstract class UiDesignerAction : ActionItem {
+
+  override var requiresUIThread: Boolean = true
+  override var location: Location = UI_DESIGNER_TOOLBAR
+  override var label: String = ""
+  override var icon: Drawable? = null
+  override var enabled: Boolean = true
+  override var visible: Boolean = true
+
+  override fun prepare(data: ActionData) {
+    if (!data.hasRequiredData(Context::class.java, Fragment::class.java)) {
+      markInvisible()
+      return
+    }
+  }
+
+  fun ActionData.requireActivity(): UIDesignerActivity {
+    return get(Context::class.java) as? UIDesignerActivity
+      ?: throw IllegalArgumentException("UIDesignerActivity instance is required in ActionData")
+  }
+
+  fun ActionData.requireWorkspace(): DesignerWorkspaceFragment {
+    return get(Fragment::class.java) as? DesignerWorkspaceFragment
+      ?: throw IllegalArgumentException(
+        "DesignerWorkspaceFragment instance is required in ActionData"
+      )
+  }
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/actions/UndoAction.kt

@@ -0,0 +1,50 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.actions
+
+import android.content.Context
+import androidx.core.content.ContextCompat
+import com.itsaky.androidide.actions.ActionData
+import com.itsaky.androidide.actions.hasRequiredData
+import com.itsaky.androidide.uidesigner.R
+
+/**
+ * Undo action for UI Designer.
+ *
+ * @author Akash Yadav
+ */
+class UndoAction(context: Context) : UiDesignerAction() {
+  
+  override val id: String = "ide.uidesigner.undo"
+  
+  init {
+    label = context.getString(R.string.undo)
+    icon = ContextCompat.getDrawable(context, R.drawable.ic_undo)
+  }
+  
+  override fun prepare(data: ActionData) {
+    visible = true
+    enabled = data.requireWorkspace().undoManager.canUndo()
+  }
+  
+  override fun execAction(data: ActionData): Any {
+    data.requireWorkspace().undoManager.undo()
+    data.requireActivity().invalidateOptionsMenu()
+    return true
+  }
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/actions/uiDesignerActions.kt

@@ -0,0 +1,33 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.actions
+
+import android.content.Context
+import com.itsaky.androidide.actions.ActionItem.Location.UI_DESIGNER_TOOLBAR
+import com.itsaky.androidide.actions.ActionsRegistry
+
+fun registerUiDesignerActions(context: Context) {
+  ActionsRegistry.getInstance().apply {
+    registerAction(UndoAction(context))
+    registerAction(RedoAction(context))
+  }
+}
+
+fun clearUiDesignerActions() {
+  ActionsRegistry.getInstance().clearActions(UI_DESIGNER_TOOLBAR)
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/drag/WidgetDragListener.kt

@@ -26,6 +26,8 @@ import com.itsaky.androidide.uidesigner.fragments.DesignerWorkspaceFragment.Comp
 import com.itsaky.androidide.uidesigner.models.UiView
 import com.itsaky.androidide.uidesigner.models.UiViewGroup
 import com.itsaky.androidide.uidesigner.models.UiWidget
+import kotlin.math.max
+import kotlin.math.min
 
 /**
  * Listens for drag events in the given view group.
@@ -69,9 +71,10 @@ internal class WidgetDragListener(val view: UiViewGroup, private val placeholder
             else -> throw IllegalArgumentException("A local state of UiWidget or IView is expected")
           }
 
-        val index = view.indexOfChild(this.placeholder)
+        var index = view.indexOfChild(this.placeholder) - 1
         this.placeholder.removeFromParent()
-
+        index = min(max(0, index), view.childCount)
+        
         this.view.addChild(index, child)
         this.view.onHighlightStateUpdated(false)
 

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/fragments/DesignerWorkspaceFragment.kt

@@ -27,7 +27,6 @@ import androidx.transition.ChangeBounds
 import androidx.transition.TransitionManager
 import com.blankj.utilcode.util.SizeUtils
 import com.itsaky.androidide.fragments.BaseFragment
-import com.itsaky.androidide.inflater.ILayoutInflater
 import com.itsaky.androidide.inflater.IView
 import com.itsaky.androidide.inflater.IViewGroup
 import com.itsaky.androidide.inflater.IViewGroup.SingleOnHierarchyChangeListener
@@ -48,6 +47,10 @@ import com.itsaky.androidide.uidesigner.drawable.UiViewLayeredForeground
 import com.itsaky.androidide.uidesigner.fragments.ViewInfoFragment.Companion.TAG
 import com.itsaky.androidide.uidesigner.models.PlaceholderView
 import com.itsaky.androidide.uidesigner.models.UiViewGroup
+import com.itsaky.androidide.uidesigner.undo.UndoManager
+import com.itsaky.androidide.uidesigner.undo.ViewAddedAction
+import com.itsaky.androidide.uidesigner.undo.ViewMovedAction
+import com.itsaky.androidide.uidesigner.undo.ViewRemovedAction
 import com.itsaky.androidide.uidesigner.utils.UiLayoutInflater
 import com.itsaky.androidide.uidesigner.utils.bgDesignerView
 import com.itsaky.androidide.uidesigner.utils.layeredForeground
@@ -75,6 +78,9 @@ class DesignerWorkspaceFragment : BaseFragment() {
     UiViewGroup(LayoutFile(File(""), ""), LinearLayout::class.qualifiedName!!, binding!!.workspace)
   }
 
+  val undoManager: UndoManager
+    get() = viewModel.undoManager
+
   private val placeholder by lazy {
     val view =
       View(requireContext()).apply {
@@ -98,18 +104,39 @@ class DesignerWorkspaceFragment : BaseFragment() {
         )
       }
 
-      override fun beforeViewAdded(group: IViewGroup, view: IView) {
+      private fun pushAction(view: IView, parent: IViewGroup, index: Int, added: Boolean) {
+        if (view is PlaceholderView) {
+          return
+        }
+
+        val lastAction = undoManager.peekUndo()
+
+        val action =
+          if (added && lastAction is ViewRemovedAction && lastAction.child == view) {
+            undoManager.popUndo()
+            ViewMovedAction(view, lastAction.parent, parent, lastAction.index, index)
+          } else if (added) {
+            ViewAddedAction(view, parent, index)
+          } else {
+            ViewRemovedAction(view, parent, index)
+          }
+
+        undoManager.push(action)
+        requireActivity().invalidateOptionsMenu()
+      }
+
+      override fun beforeViewAdded(group: IViewGroup, view: IView, index: Int) {
         animateLayoutChange()
       }
 
-      override fun beforeViewRemoved(group: IViewGroup, view: IView) {
+      override fun beforeViewRemoved(group: IViewGroup, view: IView, index: Int) {
         animateLayoutChange()
       }
 
-      override fun onViewAdded(group: IViewGroup, view: IView) {
+      override fun onViewAdded(group: IViewGroup, view: IView, index: Int) {
 
         if (!isInflating && view !is PlaceholderView) {
-          // when the inflation process is in progress, this method will be called
+          // when the inflation process is in progress, setupView method will be called
           // after OnInflateViewEvent
           setupView(view)
         }
@@ -117,12 +144,16 @@ class DesignerWorkspaceFragment : BaseFragment() {
         if (workspaceView.viewGroup.childCount > 0 && viewModel.workspaceScreen == SCREEN_ERROR) {
           viewModel.workspaceScreen = SCREEN_WORKSPACE
         }
+
+        pushAction(view, group, index, true)
       }
 
-      override fun onViewRemoved(group: IViewGroup, view: IView) {
+      override fun onViewRemoved(group: IViewGroup, view: IView, index: Int) {
         if (workspaceView.viewGroup.childCount == 0) {
           viewModel.errText = getString(R.string.msg_empty_ui_layout)
         }
+
+        pushAction(view, group, index, false)
       }
     }
 
@@ -170,7 +201,7 @@ class DesignerWorkspaceFragment : BaseFragment() {
 
     viewModel._workspaceScreen.observe(viewLifecycleOwner) { binding?.flipper?.displayedChild = it }
     viewModel._errText.observe(viewLifecycleOwner) { binding?.errText?.text = it }
-    
+
     inflater.inflationEventListener = this.inflateListener
     var hasError = false
     val inflated =

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/models/UiViewGroup.kt

@@ -27,7 +27,6 @@ import com.itsaky.androidide.inflater.LayoutBehavior.VERTICAL
 import com.itsaky.androidide.inflater.internal.LayoutFile
 import com.itsaky.androidide.inflater.internal.ViewAdapterIndex
 import com.itsaky.androidide.inflater.internal.ViewGroupImpl
-import com.itsaky.androidide.utils.ILogger
 
 /**
  * Extension of [IView] for the UI Designer.

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/IUiAction.kt

@@ -17,8 +17,6 @@
 
 package com.itsaky.androidide.uidesigner.undo
 
-import android.os.Parcelable
-
 /**
  * An action performed in the UI Designer.
  *

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/UndoManager.kt

@@ -24,19 +24,30 @@ package com.itsaky.androidide.uidesigner.undo
  */
 class UndoManager @JvmOverloads constructor(private var maxStackSize: Int = DEFAULT_STACK_SIZE) {
 
-  private var stackPointer = 0
-  private var stack = mutableListOf<IUiAction>()
+  internal var enabled = true
+    private set
+
+  private var undoStack = ArrayDeque<IUiAction>()
+  private var redoStack = ArrayDeque<IUiAction>()
 
   companion object {
     const val DEFAULT_STACK_SIZE = 30
   }
+  
+  fun enable() {
+    this.enabled = true
+  }
+  
+  fun disable() {
+    this.enabled = false
+  }
 
   fun canUndo(): Boolean {
-    return stackPointer > 0
+    return enabled && undoStack.isNotEmpty()
   }
 
   fun canRedo(): Boolean {
-    return stackPointer < stack.size
+    return enabled && redoStack.isNotEmpty()
   }
 
   fun undo() {
@@ -44,8 +55,13 @@ class UndoManager @JvmOverloads constructor(private var maxStackSize: Int = DEFA
       return
     }
 
-    stack[stackPointer - 1].undo()
-    --stackPointer
+    disable()
+    val action = undoStack.removeLast()
+    action.undo()
+
+    redoStack.addLast(action)
+    trimStacks()
+    enable()
   }
 
   fun redo() {
@@ -53,8 +69,13 @@ class UndoManager @JvmOverloads constructor(private var maxStackSize: Int = DEFA
       return
     }
 
-    stack[stackPointer].redo()
-    ++stackPointer
+    disable()
+    val action = redoStack.removeLast()
+    action.redo()
+
+    undoStack.addLast(action)
+    trimStacks()
+    enable()
   }
 
   /**
@@ -63,30 +84,37 @@ class UndoManager @JvmOverloads constructor(private var maxStackSize: Int = DEFA
    * @param action The action to push.
    */
   fun push(action: IUiAction) {
-    if (stack.isEmpty()) {
-      stack.add(action)
-      ++stackPointer
+    if (!enabled) {
       return
     }
     
-    removeRedoable()
-
-    stack.add(action)
-    ++stackPointer
-
-    trimStack()
+    redoStack.clear()
+    undoStack.addLast(action)
+    trimStacks()
   }
-  
-  private fun removeRedoable() {
-    while(stackPointer < stack.size) {
-      stack.removeAt(stack.size - 1)
+
+  fun peekUndo(): IUiAction? {
+    return undoStack.lastOrNull()
+  }
+
+  fun peekRedo(): IUiAction? {
+    return redoStack.lastOrNull()
+  }
+
+  fun popUndo(): IUiAction? {
+    return undoStack.removeLastOrNull()
+  }
+
+  fun popRedo(): IUiAction? {
+    return redoStack.removeLastOrNull()
+  }
+
+  private fun trimStacks() {
+    while (undoStack.size > maxStackSize) {
+      undoStack.removeFirst()
     }
-  }
-
-  private fun trimStack() {
-    while (stackPointer > 1 && stack.size > maxStackSize) {
-      stack.removeAt(0)
-      --stackPointer
+    while (redoStack.size > maxStackSize) {
+      redoStack.removeFirst()
     }
   }
 }

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/ViewAction.kt

@@ -28,8 +28,10 @@ import com.itsaky.androidide.inflater.IViewGroup
  * @property index The index of [child] in [parent].
  * @author Akash Yadav
  */
-abstract class ViewAction(protected val child: IView, protected val parent: IViewGroup) :
-  IUiAction {
-  
-  protected var index: Int = parent.indexOfChild(child)
-}
+abstract class ViewAction
+@JvmOverloads
+constructor(
+  val child: IView,
+  val parent: IViewGroup,
+  var index: Int = parent.indexOfChild(child)
+) : IUiAction

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/ViewAddedAction.kt

@@ -25,13 +25,16 @@ import com.itsaky.androidide.inflater.IViewGroup
  *
  * @author Akash Yadav
  */
-class ViewAddedAction(view: IView, parent: IViewGroup) : ViewAction(view, parent) {
-  
+class ViewAddedAction
+@JvmOverloads
+constructor(view: IView, parent: IViewGroup, index: Int = parent.indexOfChild(view)) :
+  ViewAction(view, parent, index) {
+
   override fun undo() {
     child.removeFromParent()
   }
-  
+
   override fun redo() {
     parent.addChild(index, child)
   }
-}
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/ViewMovedAction.kt

@@ -35,11 +35,11 @@ class ViewMovedAction(
   
   override fun undo() {
     child.removeFromParent()
-    fromParent.addChild(fromIndex, child)
+    fromParent.addChild(fromParent.validateIndex(fromIndex), child)
   }
 
   override fun redo() {
     child.removeFromParent()
-    toParent.addChild(toIndex, child)
+    toParent.addChild(toParent.validateIndex(toIndex), child)
   }
 }

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/ViewRemovedAction.kt

@@ -19,23 +19,22 @@ package com.itsaky.androidide.uidesigner.undo
 
 import com.itsaky.androidide.inflater.IView
 import com.itsaky.androidide.inflater.IViewGroup
+import kotlin.math.max
+import kotlin.math.min
 
 /**
  * Represents the action when the user removes a view from a view group.
  *
  * @author Akash Yadav
  */
-class ViewRemovedAction(child: IView, parent: IViewGroup, index: Int) : ViewAction(child, parent) {
-  
-  init {
-    this.index = index
-  }
-  
+class ViewRemovedAction(child: IView, parent: IViewGroup, index: Int) :
+  ViewAction(child, parent, index) {
+
   override fun undo() {
-    parent.addChild(index, child)
+    parent.addChild(parent.validateIndex(index), child)
   }
-  
+
   override fun redo() {
-    parent.removeChild(child)
+    child.removeFromParent()
   }
-}
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/undo/undoUtils.kt

@@ -0,0 +1,26 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.undo
+
+import com.itsaky.androidide.inflater.IViewGroup
+import kotlin.math.max
+import kotlin.math.min
+
+internal fun IViewGroup.validateIndex(index: Int) : Int {
+  return min(max(0, index), childCount)
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/utils/WorkspaceHierarchyChangeListener.kt

@@ -0,0 +1,43 @@
+/*
+ *  This file is part of AndroidIDE.
+ *
+ *  AndroidIDE is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  AndroidIDE is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.itsaky.androidide.uidesigner.utils
+
+import androidx.transition.ChangeBounds
+import androidx.transition.TransitionManager
+import com.itsaky.androidide.inflater.IView
+import com.itsaky.androidide.inflater.IViewGroup
+import com.itsaky.androidide.inflater.viewGroup
+import com.itsaky.androidide.uidesigner.R
+import com.itsaky.androidide.uidesigner.fragments.DesignerWorkspaceFragment
+import com.itsaky.androidide.uidesigner.models.PlaceholderView
+import com.itsaky.androidide.uidesigner.models.UiViewGroup
+import com.itsaky.androidide.uidesigner.undo.ViewMovedAction
+import com.itsaky.androidide.uidesigner.viewmodel.WorkspaceViewModel
+
+/**
+ * Handles hierarchy changes in the UI Designer's workspace.
+ *
+ * @author Akash Yadav
+ */
+internal class WorkspaceHierarchyChangeListener(
+  private val viewModel: WorkspaceViewModel,
+  private val workspaceView: UiViewGroup
+) : IViewGroup.SingleOnHierarchyChangeListener() {
+
+
+}

uidesigner/src/main/java/com/itsaky/androidide/uidesigner/viewmodel/WorkspaceViewModel.kt

@@ -21,6 +21,7 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import com.itsaky.androidide.inflater.IAttribute
 import com.itsaky.androidide.inflater.IView
+import com.itsaky.androidide.uidesigner.undo.UndoManager
 import java.io.File
 
 class WorkspaceViewModel : ViewModel() {
@@ -30,6 +31,7 @@ class WorkspaceViewModel : ViewModel() {
   internal val _viewInfoScreen = MutableLiveData(SCREEN_VIEW_INFO)
   internal val _view = MutableLiveData<IView>(null)
   internal val _selectedAttr = MutableLiveData<IAttribute>(null)
+  internal val _undoManager = MutableLiveData(UndoManager())
   private val _file = MutableLiveData<File>()
 
   companion object {
@@ -38,6 +40,9 @@ class WorkspaceViewModel : ViewModel() {
     const val SCREEN_VIEW_INFO = 0
     const val SCREEN_VALUE_EDITOR = 1
   }
+  
+  val undoManager: UndoManager
+    get() = this._undoManager.value!!
 
   var file: File
     get() = _file.value!!

xml-inflater/src/main/java/com/itsaky/androidide/inflater/IViewGroup.kt

@@ -110,7 +110,7 @@ interface IViewGroup : IView {
      * @param group The group in which the view will be added.
      * @param view The view that will be added to the given view group.
      */
-    fun beforeViewAdded(group: IViewGroup, view: IView) {}
+    fun beforeViewAdded(group: IViewGroup, view: IView, index: Int) {}
   
     /**
      * Called just before the [view] is removed from the [group].
@@ -118,7 +118,7 @@ interface IViewGroup : IView {
      * @param group The group from which the view will be removed.
      * @param view The view that will be removed from the given view group.
      */
-    fun beforeViewRemoved(group: IViewGroup, view: IView) {}
+    fun beforeViewRemoved(group: IViewGroup, view: IView, index: Int) {}
     
     /**
      * Called when a view is added.
@@ -126,7 +126,7 @@ interface IViewGroup : IView {
      * @param group The view group in which the view was added.
      * @param view The added view.
      */
-    fun onViewAdded(group: IViewGroup, view: IView)
+    fun onViewAdded(group: IViewGroup, view: IView, index: Int)
 
     /**
      * Called when a view is removed.
@@ -134,12 +134,12 @@ interface IViewGroup : IView {
      * @param group The view group from which the view was removed.
      * @param view The removed view.
      */
-    fun onViewRemoved(group: IViewGroup, view: IView)
+    fun onViewRemoved(group: IViewGroup, view: IView, index: Int)
   }
 
   /** Allows overriding a single method in [OnHierarchyChangeListener]. */
   open class SingleOnHierarchyChangeListener : OnHierarchyChangeListener {
-    override fun onViewAdded(group: IViewGroup, view: IView) {}
-    override fun onViewRemoved(group: IViewGroup, view: IView) {}
+    override fun onViewAdded(group: IViewGroup, view: IView, index: Int) {}
+    override fun onViewRemoved(group: IViewGroup, view: IView, index: Int) {}
   }
 }

xml-inflater/src/main/java/com/itsaky/androidide/inflater/internal/ViewGroupImpl.kt

@@ -42,20 +42,21 @@ open class ViewGroupImpl(file: LayoutFile, name: String, view: ViewGroup) :
     if (view.parent != null) {
       throw IllegalStateException("View already has a parent")
     }
-    notifyBeforeViewAdded(view)
+    notifyBeforeViewAdded(view, index)
     val idx = if (index < 0) childCount else index
     this.children.add(idx, view)
     this.view.addView(view.view, idx)
     view.parent = this
-    notifyOnViewAdded(view)
+    notifyOnViewAdded(view, index)
   }
 
   override fun removeChild(view: IView) {
-    notifyBeforeViewRemoved(view)
+    val index = indexOfChild(view)
+    notifyBeforeViewRemoved(view, index)
     this.view.removeView(view.view)
     this.children.remove(view)
     view.parent = null
-    notifyOnViewRemoved(view)
+    notifyOnViewRemoved(view, index)
   }
 
   override fun removeChild(index: Int) {
@@ -88,20 +89,20 @@ open class ViewGroupImpl(file: LayoutFile, name: String, view: ViewGroup) :
     this.hierarchyChangeListeners.remove(listener)
   }
 
-  protected open fun notifyBeforeViewAdded(child: IView) {
-    this.hierarchyChangeListeners.forEach { it.beforeViewAdded(this, child) }
+  protected open fun notifyBeforeViewAdded(child: IView, index: Int) {
+    this.hierarchyChangeListeners.forEach { it.beforeViewAdded(this, child, index) }
   }
 
-  protected open fun notifyBeforeViewRemoved(child: IView) {
-    this.hierarchyChangeListeners.forEach { it.beforeViewRemoved(this, child) }
+  protected open fun notifyBeforeViewRemoved(child: IView, index: Int) {
+    this.hierarchyChangeListeners.forEach { it.beforeViewRemoved(this, child, index) }
   }
 
-  protected open fun notifyOnViewAdded(child: IView) {
-    this.hierarchyChangeListeners.forEach { it.onViewAdded(this, child) }
+  protected open fun notifyOnViewAdded(child: IView, index: Int) {
+    this.hierarchyChangeListeners.forEach { it.onViewAdded(this, child, index) }
   }
 
-  protected open fun notifyOnViewRemoved(child: IView) {
-    this.hierarchyChangeListeners.forEach { it.onViewRemoved(this, child) }
+  protected open fun notifyOnViewRemoved(child: IView, index: Int) {
+    this.hierarchyChangeListeners.forEach { it.onViewRemoved(this, child, index) }
   }
 
   override fun immutableCopy(): IViewGroup {