enable center snapping for font picker

Summary: This diff: 1. Adds custom snap helper support to the LazyList litho component 2. Adds a custom snap helper for the text tool font helper that snaps elements to the center of the screen. This was previously broken such that first and last element couldnt be selected. Reviewed By: astreet Differential Revision: D66485165 fbshipit-source-id: 1d765dde730424db7d0db6f5a13723b31e66c8c5
facebook · Dec 10, 2024 · 6f417c9 · 6f417c9
1 parent 3145757
commit 6f417c9
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diff --git a/litho-widget-kotlin/src/main/kotlin/com/facebook/litho/widget/collection/CollectionLayout.kt b/litho-widget-kotlin/src/main/kotlin/com/facebook/litho/widget/collection/CollectionLayout.kt
@@ -18,6 +18,7 @@ package com.facebook.litho.widget.collection
 
 import androidx.annotation.Px
 import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.SnapHelper
 import androidx.recyclerview.widget.StaggeredGridLayoutManager
 import com.facebook.litho.ComponentContext
 import com.facebook.litho.config.PreAllocationHandler
@@ -114,6 +115,7 @@ internal object CollectionLayouts {
       isCircular: Boolean,
       enableStableIds: Boolean,
       linearLayoutInfoFactory: LinearLayoutInfoFactory?,
+      snapHelper: SnapHelper?,
   ): CollectionLayout =
       object :
           CollectionLayout(
@@ -132,6 +134,11 @@ internal object CollectionLayouts {
                 .snapMode(snapMode)
                 .linearLayoutInfoFactory(linearLayoutInfoFactory)
                 .snapToStartOffset(snapToStartOffset)
+                .also {
+                  if (snapHelper != null) {
+                    it.snapHelper(snapHelper)
+                  }
+                }
       }
 
   /**

diff --git a/litho-widget-kotlin/src/main/kotlin/com/facebook/litho/widget/collection/LazyList.kt b/litho-widget-kotlin/src/main/kotlin/com/facebook/litho/widget/collection/LazyList.kt
@@ -17,6 +17,7 @@
 package com.facebook.litho.widget.collection
 
 import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.SnapHelper
 import com.facebook.litho.Component
 import com.facebook.litho.Handle
 import com.facebook.litho.LithoStartupLogger
@@ -36,6 +37,7 @@ import com.facebook.rendercore.dp
 inline fun ResourcesScope.LazyList(
     @RecyclerView.Orientation orientation: Int = RecyclerView.VERTICAL,
     @SnapUtil.SnapMode snapMode: Int = SnapUtil.SNAP_NONE,
+    snapHelper: SnapHelper? = null,
     snapToStartOffset: Dimen = 0.dp,
     reverse: Boolean = false,
     crossAxisWrapMode: CrossAxisWrapMode = CrossAxisWrapMode.NoWrap,
@@ -95,6 +97,7 @@ inline fun ResourcesScope.LazyList(
               componentContext = context,
               orientation = orientation,
               snapMode = snapMode,
+              snapHelper = snapHelper,
               snapToStartOffset = snapToStartOffset.toPixels(resourceResolver),
               reverse = reverse,
               rangeRatio = rangeRatio,