From 1fc2f8728bafb75edf8e7f97bc0eb093ff972965 Mon Sep 17 00:00:00 2001
From: WangYi <wangyi@windimg.com>
Date: Thu, 2 Apr 2020 16:07:54 +0800
Subject: [PATCH] Support auto skeleton item size calculation.

---
 .../skeletonlayout/SkeletonExtensions.kt      |  4 +-
 .../SkeletonRecyclerViewAdapter.kt            | 54 ++++++++++++++++---
 2 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/SkeletonExtensions.kt b/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/SkeletonExtensions.kt
index 8e4351a..ae5d0ea 100644
--- a/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/SkeletonExtensions.kt
+++ b/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/SkeletonExtensions.kt
@@ -10,7 +10,7 @@ import androidx.core.content.ContextCompat
 import androidx.recyclerview.widget.RecyclerView
 import com.faltenreich.skeletonlayout.recyclerview.SkeletonRecyclerView
 
-private const val LIST_ITEM_COUNT_DEFAULT = 3
+private const val LIST_ITEM_COUNT_AUTO = 0
 
 /**
  * Creates a new Skeleton that wraps the given View in a SkeletonLayout
@@ -61,7 +61,7 @@ fun View.createSkeleton(
 @JvmOverloads
 fun RecyclerView.applySkeleton(
     @LayoutRes listItemLayoutResId: Int,
-    itemCount: Int = LIST_ITEM_COUNT_DEFAULT,
+    itemCount: Int = LIST_ITEM_COUNT_AUTO,
     @ColorInt maskColor: Int = ContextCompat.getColor(context, SkeletonLayout.DEFAULT_MASK_COLOR),
     cornerRadius: Float = SkeletonLayout.DEFAULT_CORNER_RADIUS,
     showShimmer: Boolean = SkeletonLayout.DEFAULT_SHIMMER_SHOW,
diff --git a/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/recyclerview/SkeletonRecyclerViewAdapter.kt b/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/recyclerview/SkeletonRecyclerViewAdapter.kt
index 68d66ff..91bb9b4 100644
--- a/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/recyclerview/SkeletonRecyclerViewAdapter.kt
+++ b/skeletonlayout/src/main/kotlin/com/faltenreich/skeletonlayout/recyclerview/SkeletonRecyclerViewAdapter.kt
@@ -1,6 +1,7 @@
 package com.faltenreich.skeletonlayout.recyclerview
 
 import android.view.LayoutInflater
+import android.view.View
 import android.view.ViewGroup
 import androidx.annotation.ColorInt
 import androidx.annotation.LayoutRes
@@ -9,24 +10,61 @@ import com.faltenreich.skeletonlayout.SkeletonLayout
 import com.faltenreich.skeletonlayout.createSkeleton
 
 internal class SkeletonRecyclerViewAdapter(
-    @LayoutRes private val layoutResId: Int,
-    private val itemCount: Int,
-    @ColorInt private val maskColor: Int,
-    private val cornerRadius: Float,
-    private val showShimmer: Boolean,
-    @ColorInt private val shimmerColor: Int,
-    private val shimmerDurationInMillis: Long
+        @LayoutRes private val layoutResId: Int,
+        private var itemCount: Int,
+        @ColorInt private val maskColor: Int,
+        private val cornerRadius: Float,
+        private val showShimmer: Boolean,
+        @ColorInt private val shimmerColor: Int,
+        private val shimmerDurationInMillis: Long
 ) : RecyclerView.Adapter<SkeletonRecyclerViewHolder>() {
 
+    private var measured = itemCount != 0
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SkeletonRecyclerViewHolder {
         val originView = LayoutInflater.from(parent.context).inflate(layoutResId, parent, false)
         val skeleton = originView.createSkeleton(maskColor, cornerRadius, showShimmer, shimmerColor, shimmerDurationInMillis) as SkeletonLayout
         skeleton.layoutParams = originView.layoutParams
         skeleton.showSkeleton()
+        // Automatic calc the skeleton item count
+        if (!measured) {
+            var itemHeight = skeleton.height
+            var parentHeight = parent.height
+            val calcItemCount = {
+                if (itemHeight != 0 && parentHeight != 0) {
+                    measured = true
+                    itemCount = parentHeight / itemHeight
+                }
+            }
+            val listener = object : View.OnLayoutChangeListener {
+                override fun onLayoutChange(v: View?, left: Int, top: Int, right: Int, bottom: Int, oldLeft: Int, oldTop: Int, oldRight: Int, oldBottom: Int) {
+                    if (top != bottom) {
+                        skeleton.removeOnLayoutChangeListener(this)
+                        when (v) {
+                            skeleton -> itemHeight = bottom - top
+                            parent -> parentHeight = bottom - top
+                        }
+                        calcItemCount()
+                    }
+                }
+            }
+            if (itemHeight == 0) {
+                skeleton.addOnLayoutChangeListener(listener)
+            }
+            if (parentHeight == 0) {
+                parent.addOnLayoutChangeListener(listener)
+            }
+            calcItemCount()
+        }
         return SkeletonRecyclerViewHolder(skeleton)
     }
 
     override fun onBindViewHolder(holder: SkeletonRecyclerViewHolder, position: Int) = Unit
 
-    override fun getItemCount() = itemCount
+    override fun getItemCount(): Int {
+        return when (measured) {
+            true -> itemCount
+            else -> 1
+        }
+    }
 }
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