feat(layout-inflater,uidesigner): move child view index computation logic to viewgroup adapters

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

@@ -17,13 +17,9 @@
 
 package com.itsaky.androidide.uidesigner.models
 
-import android.graphics.RectF
 import android.view.ViewGroup
 import com.itsaky.androidide.inflater.IView
 import com.itsaky.androidide.inflater.IViewGroupAdapter
-import com.itsaky.androidide.inflater.LayoutBehavior.HORIZONTAL
-import com.itsaky.androidide.inflater.LayoutBehavior.TOP_LEFT
-import com.itsaky.androidide.inflater.LayoutBehavior.VERTICAL
 import com.itsaky.androidide.inflater.internal.LayoutFile
 import com.itsaky.androidide.inflater.internal.ViewGroupImpl
 import com.itsaky.androidide.inflater.viewAdapter
@@ -53,74 +49,17 @@ internal class UiViewGroup(file: LayoutFile, name: String, view: ViewGroup) :
       return childCount
     }
 
-    return when (adapter.getLayoutBehavior(this)) {
-      TOP_LEFT -> childCount
-      VERTICAL -> computeViewIndexVertically(x, y)
-      HORIZONTAL -> computeViewIndexHorizontally(x, y)
-    }
+    return adapter.computeChildIndex(this, x, y)
   }
 
-  private fun computeViewIndexHorizontally(x: Float, y: Float): Int {
-    get(0).apply {
-      val rect = getViewRect(this)
-      if (x < rect.left) {
-        return 0
-      }
-    }
-    get(childCount - 1).apply {
-      val rect = getViewRect(this)
-      if (x > rect.right) {
-        return childCount
-      }
-    }
-    val (child, index) = findNearestChild(x, y, false) ?: return childCount
-    val rect = getViewRect(child)
-    val mid = rect.left + (rect.width() / 2)
-    val left = RectF(rect).apply { this.right = mid - 10 }
-    val right = RectF(rect).apply { this.left = mid + 10 }
-    if (x > left.left && x < left.right) {
-      return index - 1
-    }
-    if (x > right.left && x < right.right) {
-      return index + 1
-    }
-    return index
-  }
-
-  private fun computeViewIndexVertically(x: Float, y: Float): Int {
-    get(0).apply {
-      val rect = getViewRect(this)
-      if (y < rect.top) {
-        return 0
-      }
-    }
-    get(childCount - 1).apply {
-      val rect = getViewRect(this)
-      if (y > rect.bottom) {
-        return childCount
-      }
-    }
-    val (child, index) = findNearestChild(x, y, true) ?: return childCount
-    val rect = getViewRect(child)
-    val mid = rect.top + (rect.height() / 2)
-    val top = RectF(rect).apply { this.bottom = mid - 10 }
-    val bottom = RectF(rect).apply { this.top = mid + 10 }
-    if (y > top.top && y < top.bottom) {
-      return index - 1
-    }
-    if (y > bottom.top && y < bottom.bottom) {
-      return index + 1
-    }
-    return index
-  }
-
-  private fun findNearestChild(x: Float, y: Float, vertical: Boolean = true): Pair<IView, Int>? {
+  override fun findNearestChild(x: Float, y: Float, vertical: Boolean
+  ): Pair<IView, Int>? {
     for (i in 0 until childCount) {
       val child = get(i)
       if (child is CommonUiView && !child.includeInIndexComputation) {
         continue
       }
-      val rect = getViewRect(child)
+      val rect = child.getViewRect()
       if (vertical && (y > rect.top && y < rect.bottom)) {
         return child to i
       }
@@ -132,14 +71,4 @@ internal class UiViewGroup(file: LayoutFile, name: String, view: ViewGroup) :
 
     return null
   }
-
-  private fun getViewRect(view: IView): RectF {
-    val v = view.view
-    val rect = RectF()
-    rect.left = v.left.toFloat()
-    rect.top = v.top.toFloat()
-    rect.right = rect.left + v.width
-    rect.bottom = rect.top + v.height
-    return rect
-  }
 }

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

@@ -17,6 +17,7 @@
 
 package com.itsaky.androidide.inflater
 
+import android.graphics.RectF
 import android.view.View
 
 /**
@@ -108,6 +109,27 @@ interface IView {
    */
   fun onHighlightStateUpdated(highlight: Boolean)
 
+  /**
+   * Get the bounds of the view.
+   *
+   * @return The bounds of the view.
+   */
+  fun getViewRect(): RectF {
+    return RectF().apply { getViewRect(this) }
+  }
+
+  /**
+   * Get the bounds of the view.
+   *
+   * @return The [RectF] to store the bounds of the view.
+   */
+  fun getViewRect(out: RectF) {
+    out.left = view.left.toFloat()
+    out.top = view.top.toFloat()
+    out.right = out.left + view.width
+    out.bottom = out.top + view.height
+  }
+
   /** Removes this view from its parent view. */
   fun removeFromParent() {
     parent?.removeChild(this)
@@ -159,8 +181,12 @@ interface IView {
   }
 
   open class SingleAttributeChangeListener : AttributeChangeListener {
+
     override fun onAttributeAdded(view: IView, attribute: IAttribute) {}
     override fun onAttributeRemoved(view: IView, attribute: IAttribute) {}
-    override fun onAttributeUpdated(view: IView, attribute: IAttribute, oldValue: String) {}
+    override fun onAttributeUpdated(view: IView, attribute: IAttribute,
+                                    oldValue: String
+    ) {
+    }
   }
 }

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

@@ -51,8 +51,8 @@ interface IViewGroup : IView, Iterable<IView> {
    * view's [IViewAdapter.canAcceptChild] returns `true`.
    */
   fun canAcceptChild(name: String): Boolean {
-    return canModifyChildViews() &&
-      (this.viewAdapter as? IViewGroupAdapter)?.canAcceptChild(this, name) == true
+    return canModifyChildViews() && (this.viewAdapter as? IViewGroupAdapter)?.canAcceptChild(
+      this, name) == true
   }
 
   /**
@@ -115,6 +115,17 @@ interface IViewGroup : IView, Iterable<IView> {
     return -1
   }
 
+  /**
+   * Find the child nearest to the given coordinates.
+   *
+   * @param x The X coordinate.
+   * @param y The Y coordinate.
+   * @param vertical Whether to compare the vertical or horizontal bounds of
+   * existing child views with the given coordinates.
+   */
+  fun findNearestChild(x: Float, y: Float, vertical: Boolean = true
+  ): Pair<IView, Int>?
+
   /**
    * Adds the given hierarchy change listener.
    *
@@ -167,6 +178,7 @@ interface IViewGroup : IView, Iterable<IView> {
 
   /** Allows overriding a single method in [OnHierarchyChangeListener]. */
   open class SingleOnHierarchyChangeListener : OnHierarchyChangeListener {
+
     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/IViewGroupAdapter.kt

@@ -25,14 +25,26 @@ package com.itsaky.androidide.inflater
 interface IViewGroupAdapter {
 
   /**
-   * Get the layout behavior for the given view group and the view. Implementations must take the
+   * Get the layout strategy for the given view group and the view. Implementations must take the
    * attributes of the view group into account.
    *
-   * @param group The view group whose layout behavior should be returned.
-   * @return The layout behavior.
+   * @param group The view group whose layout strategy should be returned.
+   * @return The layout strategy.
    */
-  fun getLayoutBehavior(group: IViewGroup): LayoutBehavior
-  
+  fun getLayoutStrategy(group: IViewGroup): LayoutStrategy
+
+  /**
+   * Compute the index of the child based on the given [x] and [y] coordinates
+   * of the drag event.
+   *
+   * @param x The X coordinate of the drag event.
+   * @param y The Y coordinate of the drag event.
+   * @return The index at which the new child must be added
+   */
+  fun computeChildIndex(parent: IViewGroup, x: Float, y: Float): Int {
+    return getLayoutStrategy(parent).computeChildIndex(parent, x, y)
+  }
+
   /**
    * Called by the UI Designer to check if the given view group (which this adpater handles) can
    * accept the child view with the given qualified name.

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

@@ -1,38 +0,0 @@
-/*
- *  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.inflater
-
-/**
- * Represents how an [IViewGroup] lays its children. This is used to determine the position of the
- * view that the user drags in the UI Designer's workspace.
- *
- * @author Akash Yadav
- */
-enum class LayoutBehavior {
-
-  /** The child views are laid out vertically. */
-  VERTICAL,
-
-  /** The child views are laid out horizontally. */
-  HORIZONTAL,
-
-  /**
-   * The child views are placed on the top left corner of the view group. This is the default value.
-   */
-  TOP_LEFT
-}

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

@@ -0,0 +1,133 @@
+/*
+ *  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.inflater
+
+import android.graphics.RectF
+
+/**
+ * Represents how an [IViewGroup] lays its children. This is used to determine the position of the
+ * view that the user drags in the UI Designer's workspace.
+ *
+ * @author Akash Yadav
+ */
+interface LayoutStrategy {
+
+  companion object {
+
+    /** The child views are laid out vertically. */
+    @JvmStatic
+    val VERTICAL = VerticalLayoutStrategy()
+
+    /** The child views are laid out horizontally. */
+    @JvmStatic
+    val HORIZONTAL = HorizontalLayoutStrategy()
+
+    /**
+     * The child views are placed on the top left corner of the view group. This is the default value.
+     */
+    @JvmStatic
+    val TOP_LEFT = TopLeftLayoutStrategy()
+  }
+
+  /**
+   * Compute the index of the child based on the given [x] and [y] coordinates
+   * of the drag event.
+   *
+   * @param x The X coordinate of the drag event.
+   * @param y The Y coordinate of the drag event.
+   * @return The index at which the new child must be added
+   */
+  fun computeChildIndex(parent: IViewGroup, x: Float, y: Float) : Int
+
+  class TopLeftLayoutStrategy : LayoutStrategy {
+    override fun computeChildIndex(parent: IViewGroup, x: Float, y: Float): Int {
+      return parent.childCount
+    }
+  }
+
+  class VerticalLayoutStrategy : LayoutStrategy {
+
+    override fun computeChildIndex(parent: IViewGroup, x: Float, y: Float
+    ): Int {
+      return parent.run {
+        get(0).apply {
+          val rect = getViewRect()
+          if (y < rect.top) {
+            return@run 0
+          }
+        }
+
+        get(childCount - 1).apply {
+          val rect = getViewRect()
+          if (y > rect.bottom) {
+            return@run childCount
+          }
+        }
+
+        val (child, index) = findNearestChild(x, y, true) ?: return@run childCount
+        val rect = child.getViewRect()
+        val mid = rect.top + (rect.height() / 2)
+        val top = RectF(rect).apply { this.bottom = mid - 10 }
+        val bottom = RectF(rect).apply { this.top = mid + 10 }
+
+        if (y > top.top && y < top.bottom) {
+          return@run index - 1
+        }
+
+        if (y > bottom.top && y < bottom.bottom) {
+          return@run index + 1
+        }
+
+        return@run index
+      }
+    }
+  }
+
+  class HorizontalLayoutStrategy : LayoutStrategy {
+
+    override fun computeChildIndex(parent: IViewGroup, x: Float, y: Float): Int {
+      return parent.run {
+        get(0).apply {
+          val rect = getViewRect()
+          if (x < rect.left) {
+            return@run 0
+          }
+        }
+        get(childCount - 1).apply {
+          val rect = getViewRect()
+          if (x > rect.right) {
+            return@run childCount
+          }
+        }
+        val (child, index) = findNearestChild(x, y, false) ?: return@run childCount
+        val rect = child.getViewRect()
+        val mid = rect.left + (rect.width() / 2)
+        val left = RectF(rect).apply { this.right = mid - 10 }
+        val right = RectF(rect).apply { this.left = mid + 10 }
+        if (x > left.left && x < left.right) {
+          return@run index - 1
+        }
+        if (x > right.left && x < right.right) {
+          return@run index + 1
+        }
+
+        return@run index
+      }
+    }
+  }
+}

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

@@ -29,9 +29,7 @@ import com.itsaky.androidide.inflater.AttributeHandlerScope
 import com.itsaky.androidide.inflater.INamespace
 import com.itsaky.androidide.inflater.IView
 import com.itsaky.androidide.inflater.IViewGroup
-import com.itsaky.androidide.inflater.LayoutBehavior
-import com.itsaky.androidide.inflater.LayoutBehavior.HORIZONTAL
-import com.itsaky.androidide.inflater.LayoutBehavior.VERTICAL
+import com.itsaky.androidide.inflater.LayoutStrategy
 import com.itsaky.androidide.inflater.internal.LayoutFile
 import com.itsaky.androidide.inflater.models.UiWidget
 import com.itsaky.androidide.inflater.utils.newAttribute
@@ -47,7 +45,9 @@ import com.itsaky.androidide.resources.R.string
 @IncludeInDesigner(group = LAYOUTS)
 open class LinearLayoutAdapter<T : LinearLayout> : ViewGroupAdapter<T>() {
 
-  override fun createAttrHandlers(create: (String, AttributeHandlerScope<T>.() -> Unit) -> Unit) {
+  override fun createAttrHandlers(
+    create: (String, AttributeHandlerScope<T>.() -> Unit) -> Unit
+  ) {
     super.createAttrHandlers(create)
 
     create("baselineAligned") { view.isBaselineAligned = parseBoolean(value) }
@@ -64,23 +64,16 @@ open class LinearLayoutAdapter<T : LinearLayout> : ViewGroupAdapter<T>() {
 
   override fun createUiWidgets(): List<UiWidget> {
     val horizontal =
-      LinearLayoutWidget(
-        title = string.widget_linear_layout_horz,
-        icon = drawable.ic_widget_linear_layout_horz,
-        isVertical = false
-      )
-    val vertical =
-      LinearLayoutWidget(
-        title = string.widget_linear_layout_vert,
-        icon = drawable.ic_widget_linear_layout_vert,
-        isVertical = true
-      )
+      LinearLayoutWidget(title = string.widget_linear_layout_horz,
+        icon = drawable.ic_widget_linear_layout_horz, isVertical = false)
+    val vertical = LinearLayoutWidget(title = string.widget_linear_layout_vert,
+      icon = drawable.ic_widget_linear_layout_vert, isVertical = true)
     return listOf(horizontal, vertical)
   }
 
-  override fun getLayoutBehavior(group: IViewGroup): LayoutBehavior {
+  override fun getLayoutStrategy(group: IViewGroup): LayoutStrategy {
     val orientation = group.findAttribute("orientation", INamespace.ANDROID.uri)
-    return if (orientation?.value == "vertical") VERTICAL else HORIZONTAL
+    return if (orientation?.value == "vertical") LayoutStrategy.VERTICAL else LayoutStrategy.HORIZONTAL
   }
 
   protected open fun parseOrientation(value: String): Int {
@@ -91,22 +84,23 @@ open class LinearLayoutAdapter<T : LinearLayout> : ViewGroupAdapter<T>() {
     }
   }
 
-  private class LinearLayoutWidget(
-    @StringRes title: Int,
-    @DrawableRes icon: Int,
-    private val isVertical: Boolean
+  private class LinearLayoutWidget(@StringRes title: Int,
+                                   @DrawableRes icon: Int,
+                                   private val isVertical: Boolean
   ) : UiWidget(LinearLayout::class.java, title, icon) {
 
     companion object {
+
       private const val HORIZONTAL = "horizontal"
       private const val VERTICAL = "vertical"
     }
 
-    override fun createView(context: Context, parent: ViewGroup, layoutFile: LayoutFile): IView {
+    override fun createView(context: Context, parent: ViewGroup,
+                            layoutFile: LayoutFile
+    ): IView {
       return super.createView(context, parent, layoutFile).apply {
-        addAttribute(
-          newAttribute(this, name = "orientation", value = if (isVertical) VERTICAL else HORIZONTAL)
-        )
+        addAttribute(newAttribute(this, name = "orientation",
+          value = if (isVertical) VERTICAL else HORIZONTAL))
       }
     }
   }

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

@@ -22,19 +22,24 @@ import android.view.ViewGroup
 import com.itsaky.androidide.inflater.AttributeHandlerScope
 import com.itsaky.androidide.inflater.IViewGroup
 import com.itsaky.androidide.inflater.IViewGroupAdapter
-import com.itsaky.androidide.inflater.LayoutBehavior
-import com.itsaky.androidide.inflater.LayoutBehavior.TOP_LEFT
+import com.itsaky.androidide.inflater.LayoutStrategy
+import com.itsaky.androidide.inflater.LayoutStrategy.Companion.TOP_LEFT
 
 /**
  * Base attribute adapter for all [ViewGroup].
  *
  * @author Akash Yadav
  */
-abstract class ViewGroupAdapter<T : ViewGroup> : ViewAdapter<T>(), IViewGroupAdapter {
+abstract class ViewGroupAdapter<T : ViewGroup> : ViewAdapter<T>(),
+                                                 IViewGroupAdapter {
 
-  override fun createAttrHandlers(create: (String, AttributeHandlerScope<T>.() -> Unit) -> Unit) {
+  override fun createAttrHandlers(
+    create: (String, AttributeHandlerScope<T>.() -> Unit) -> Unit
+  ) {
     super.createAttrHandlers(create)
-    create("animateLayoutChanges") { view.layoutTransition = LayoutTransition() }
+    create("animateLayoutChanges") {
+      view.layoutTransition = LayoutTransition()
+    }
     create("clipChildren") { view.clipChildren = parseBoolean(value) }
     create("clipToPadding") { view.clipToPadding = parseBoolean(value) }
     create("descendantFocusability") {
@@ -43,7 +48,7 @@ abstract class ViewGroupAdapter<T : ViewGroup> : ViewAdapter<T>(), IViewGroupAda
     create("layoutMode") { view.layoutMode = parseLayoutMode(value) }
   }
 
-  override fun getLayoutBehavior(group: IViewGroup): LayoutBehavior {
+  override fun getLayoutStrategy(group: IViewGroup): LayoutStrategy {
     return TOP_LEFT
   }