From d3f3bfa2a5835cc66d9d4cf9f6dba05607e17c22 Mon Sep 17 00:00:00 2001
From: Krzysztof Sroka <kpsroka@users.noreply.github.com>
Date: Tue, 27 Nov 2018 11:19:41 -0800
Subject: [PATCH] Added `persistentScrollbar` prop in ScrollView component
 (#22300)

Summary:
This PR is a follow-up from the closed [discussions-and-proposals PR](https://github.com/react-native-community/discussions-and-proposals/pull/39), that explains in more detail the rationale for adding this feature.
Pull Request resolved: https://github.com/facebook/react-native/pull/22300

Reviewed By: fkgozali

Differential Revision: D13121748

Pulled By: mdvacca

fbshipit-source-id: 899641be79bdb41fa6649df0772c602a5e09b3b9
---
 Libraries/Components/ScrollView/ScrollView.js             | 8 ++++++++
 Libraries/Lists/VirtualizedList.js                        | 1 +
 .../views/scroll/ReactHorizontalScrollViewManager.java    | 5 +++++
 .../react/views/scroll/ReactScrollViewManager.java        | 5 +++++
 4 files changed, 19 insertions(+)

diff --git a/Libraries/Components/ScrollView/ScrollView.js b/Libraries/Components/ScrollView/ScrollView.js
index f1c222526..290541584 100644
--- a/Libraries/Components/ScrollView/ScrollView.js
+++ b/Libraries/Components/ScrollView/ScrollView.js
@@ -301,6 +301,13 @@ type AndroidProps = $ReadOnly<{|
    * @platform android
    */
   overScrollMode?: ?('auto' | 'always' | 'never'),
+  /**
+   * Causes the scrollbars not to turn transparent when they are not in use.
+   * The default value is false.
+   *
+   * @platform android
+   */
+  persistentScrollbar?: ?boolean,
 |}>;
 
 type VRProps = $ReadOnly<{|
@@ -442,6 +449,7 @@ export type Props = $ReadOnly<{|
    * Note: Vertical pagination is not supported on Android.
    */
   pagingEnabled?: ?boolean,
+
   /**
    * When false, the view cannot be scrolled via touch interaction.
    * The default value is true.
diff --git a/Libraries/Lists/VirtualizedList.js b/Libraries/Lists/VirtualizedList.js
index 9e10cbee4..61af5ea0a 100644
--- a/Libraries/Lists/VirtualizedList.js
+++ b/Libraries/Lists/VirtualizedList.js
@@ -175,6 +175,7 @@ type OptionalProps = {
     viewableItems: Array<ViewToken>,
     changed: Array<ViewToken>,
   }) => void,
+  persistentScrollbar?: ?boolean,
   /**
    * Set this when offset is needed for the loading indicator to show correctly.
    * @platform android
diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java b/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java
index 5ea8096ff..6c7ff1a21 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java
@@ -255,4 +255,9 @@ public class ReactHorizontalScrollViewManager
   public void setOverflow(ReactHorizontalScrollView view, @Nullable String overflow) {
     view.setOverflow(overflow);
   }
+
+  @ReactProp(name = "persistentScrollbar")
+  public void setPersistentScrollbar(ReactHorizontalScrollView view, boolean value) {
+    view.setScrollbarFadingEnabled(!value);
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java b/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java
index 24eaee6d4..b0a77556b 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java
@@ -264,6 +264,11 @@ public class ReactScrollViewManager
     }
   }
 
+  @ReactProp(name = "persistentScrollbar")
+  public void setPersistentScrollbar(ReactScrollView view, boolean value) {
+    view.setScrollbarFadingEnabled(!value);
+  }
+
   @Override
   public @Nullable Map<String, Object> getExportedCustomDirectEventTypeConstants() {
     return createExportedCustomDirectEventTypeConstants();