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roryabrahamjanicduplessis
roryabraham
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janicduplessis
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Add maintainVisibleContentPosition prop for android scroll view
1 parent 950ea91 commit c069ae3

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8 files changed

+322
-11
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8 files changed

+322
-11
lines changed

‎Libraries/Components/ScrollView/ScrollView.js‎

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@@ -279,7 +279,6 @@ type IOSProps = $ReadOnly<{|
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* visibility. Occlusion, transforms, and other complexity won't be taken into account as to
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* whether content is "visible" or not.
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*
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* @platform ios
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*/
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maintainVisibleContentPosition?: ?$ReadOnly<{|
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minIndexForVisible: number,

‎ReactAndroid/src/main/java/com/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper.java‎

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@@ -0,0 +1,186 @@
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/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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package com.facebook.react.views.scroll;
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import android.graphics.Rect;
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import android.view.View;
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import android.view.ViewGroup;
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import androidx.annotation.Nullable;
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import com.facebook.infer.annotation.Assertions;
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import com.facebook.react.bridge.ReactContext;
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import com.facebook.react.bridge.ReadableMap;
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import com.facebook.react.bridge.UIManager;
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import com.facebook.react.bridge.UIManagerListener;
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import com.facebook.react.bridge.UiThreadUtil;
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import com.facebook.react.uimanager.UIManagerHelper;
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import com.facebook.react.uimanager.common.ViewUtil;
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import com.facebook.react.views.view.ReactViewGroup;
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import com.facebook.react.views.scroll.ReactScrollViewHelper.HasSmoothScroll;
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import java.lang.ref.WeakReference;
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/**
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* Manage state for the maintainVisibleContentPosition prop.
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*
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* This uses UIManager to listen to updates and capture position of items before and after layout.
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*/
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public class MaintainVisibleScrollPositionHelper<ScrollViewT extends ViewGroup & HasSmoothScroll> implements UIManagerListener {
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private final ScrollViewT mScrollView;
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private final boolean mHorizontal;
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private @Nullable Config mConfig;
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private @Nullable WeakReference<View> mFirstVisibleView = null;
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private @Nullable Rect mPrevFirstVisibleFrame = null;
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private boolean mListening = false;
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public static class Config {
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public final int minIndexForVisible;
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public final @Nullable Integer autoScrollToTopThreshold;
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Config(int minIndexForVisible, @Nullable Integer autoScrollToTopThreshold) {
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this.minIndexForVisible = minIndexForVisible;
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this.autoScrollToTopThreshold = autoScrollToTopThreshold;
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}
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static Config fromReadableMap(ReadableMap value) {
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int minIndexForVisible = value.getInt("minIndexForVisible");
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Integer autoScrollToTopThreshold =
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value.hasKey("autoscrollToTopThreshold")
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? value.getInt("autoscrollToTopThreshold")
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: null;
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return new Config(minIndexForVisible, autoScrollToTopThreshold);
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}
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}
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public MaintainVisibleScrollPositionHelper(ScrollViewT scrollView, boolean horizontal) {
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mScrollView = scrollView;
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mHorizontal = horizontal;
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}
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public void setConfig(@Nullable Config config) {
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mConfig = config;
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}
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/**
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* Start listening to view hierarchy updates. Should be called when this is created.
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*/
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public void start() {
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if (mListening) {
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return;
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}
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mListening = true;
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getUIManagerModule().addUIManagerEventListener(this);
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}
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/**
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* Stop listening to view hierarchy updates. Should be called before this is destroyed.
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*/
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public void stop() {
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if (!mListening) {
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return;
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}
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mListening = false;
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getUIManagerModule().removeUIManagerEventListener(this);
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}
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/**
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* Update the scroll position of the managed ScrollView. This should be called after layout
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* has been updated.
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*/
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public void updateScrollPosition() {
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if (mConfig == null
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|| mFirstVisibleView == null
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|| mPrevFirstVisibleFrame == null) {
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return;
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}
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View firstVisibleView = mFirstVisibleView.get();
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Rect newFrame = new Rect();
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firstVisibleView.getHitRect(newFrame);
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if (mHorizontal) {
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int deltaX = newFrame.left - mPrevFirstVisibleFrame.left;
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if (deltaX != 0) {
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int scrollX = mScrollView.getScrollX();
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mScrollView.scrollTo(scrollX + deltaX, mScrollView.getScrollY());
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mPrevFirstVisibleFrame = newFrame;
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if (mConfig.autoScrollToTopThreshold != null && scrollX <= mConfig.autoScrollToTopThreshold) {
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mScrollView.reactSmoothScrollTo(0, mScrollView.getScrollY());
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}
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}
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} else {
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int deltaY = newFrame.top - mPrevFirstVisibleFrame.top;
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if (deltaY != 0) {
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int scrollY = mScrollView.getScrollY();
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mScrollView.scrollTo(mScrollView.getScrollX(), scrollY + deltaY);
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mPrevFirstVisibleFrame = newFrame;
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if (mConfig.autoScrollToTopThreshold != null && scrollY <= mConfig.autoScrollToTopThreshold) {
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mScrollView.reactSmoothScrollTo(mScrollView.getScrollX(), 0);
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}
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}
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}
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}
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private @Nullable ReactViewGroup getContentView() {
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return (ReactViewGroup) mScrollView.getChildAt(0);
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}
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private UIManager getUIManagerModule() {
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return Assertions.assertNotNull(
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UIManagerHelper.getUIManager(
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(ReactContext) mScrollView.getContext(),
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ViewUtil.getUIManagerType(mScrollView.getId())));
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}
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private void computeTargetView() {
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if (mConfig == null) {
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return;
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}
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ReactViewGroup contentView = getContentView();
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if (contentView == null) {
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return;
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}
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int currentScroll = mHorizontal ? mScrollView.getScrollX() : mScrollView.getScrollY();
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for (int i = mConfig.minIndexForVisible; i < contentView.getChildCount(); i++) {
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View child = contentView.getChildAt(i);
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float position = mHorizontal ? child.getX() : child.getY();
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if (position > currentScroll || i == contentView.getChildCount() - 1) {
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mFirstVisibleView = new WeakReference<>(child);
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Rect frame = new Rect();
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child.getHitRect(frame);
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mPrevFirstVisibleFrame = frame;
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break;
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}
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}
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}
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// UIManagerListener
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@Override
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public void willDispatchViewUpdates(final UIManager uiManager) {
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UiThreadUtil.runOnUiThread(
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new Runnable() {
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@Override
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public void run() {
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computeTargetView();
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}
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});
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}
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@Override
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public void didDispatchMountItems(UIManager uiManager) {
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// noop
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}
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@Override
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public void didScheduleMountItems(UIManager uiManager) {
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// noop
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}
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}

‎ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollView.java‎

Lines changed: 65 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -45,6 +45,7 @@
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import com.facebook.react.views.scroll.ReactScrollViewHelper.HasFlingAnimator;
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import com.facebook.react.views.scroll.ReactScrollViewHelper.HasScrollEventThrottle;
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import com.facebook.react.views.scroll.ReactScrollViewHelper.HasScrollState;
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import com.facebook.react.views.scroll.ReactScrollViewHelper.HasSmoothScroll;
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import com.facebook.react.views.scroll.ReactScrollViewHelper.ReactScrollViewScrollState;
4950
import com.facebook.react.views.view.ReactViewBackgroundManager;
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import java.lang.reflect.Field;
@@ -54,11 +55,14 @@
5455
/** Similar to {@link ReactScrollView} but only supports horizontal scrolling. */
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public class ReactHorizontalScrollView extends HorizontalScrollView
5657
implements ReactClippingViewGroup,
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ViewGroup.OnHierarchyChangeListener,
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View.OnLayoutChangeListener,
5760
FabricViewStateManager.HasFabricViewStateManager,
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ReactOverflowViewWithInset,
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HasScrollState,
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HasFlingAnimator,
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HasScrollEventThrottle {
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HasScrollEventThrottle,
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HasSmoothScroll {
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6367
private static boolean DEBUG_MODE = false && ReactBuildConfig.DEBUG;
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private static String TAG = ReactHorizontalScrollView.class.getSimpleName();
@@ -107,6 +111,8 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
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private PointerEvents mPointerEvents = PointerEvents.AUTO;
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private long mLastScrollDispatchTime = 0;
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private int mScrollEventThrottle = 0;
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private @Nullable View mContentView;
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private @Nullable MaintainVisibleScrollPositionHelper mMaintainVisibleContentPositionHelper = null;
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111117
private final Rect mTempRect = new Rect();
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@@ -127,6 +133,8 @@ public ReactHorizontalScrollView(Context context, @Nullable FpsListener fpsListe
127133
I18nUtil.getInstance().isRTL(context)
128134
? ViewCompat.LAYOUT_DIRECTION_RTL
129135
: ViewCompat.LAYOUT_DIRECTION_LTR);
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setOnHierarchyChangeListener(this);
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}
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132140
public boolean getScrollEnabled() {
@@ -243,6 +251,19 @@ public void setOverflow(String overflow) {
243251
invalidate();
244252
}
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254+
public void setMaintainVisibleContentPosition(@Nullable MaintainVisibleScrollPositionHelper.Config config) {
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if (config != null && mMaintainVisibleContentPositionHelper == null) {
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mMaintainVisibleContentPositionHelper = new MaintainVisibleScrollPositionHelper(this, true);
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mMaintainVisibleContentPositionHelper.start();
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} else if (config == null && mMaintainVisibleContentPositionHelper != null) {
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mMaintainVisibleContentPositionHelper.stop();
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mMaintainVisibleContentPositionHelper = null;
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}
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if (mMaintainVisibleContentPositionHelper != null) {
263+
mMaintainVisibleContentPositionHelper.setConfig(config);
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}
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}
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246267
@Override
247268
public @Nullable String getOverflow() {
248269
return mOverflow;
@@ -635,6 +656,17 @@ protected void onAttachedToWindow() {
635656
if (mRemoveClippedSubviews) {
636657
updateClippingRect();
637658
}
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if (mMaintainVisibleContentPositionHelper != null) {
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mMaintainVisibleContentPositionHelper.start();
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}
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}
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@Override
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protected void onDetachedFromWindow() {
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super.onDetachedFromWindow();
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if (mMaintainVisibleContentPositionHelper != null) {
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mMaintainVisibleContentPositionHelper.stop();
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}
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}
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640672
@Override
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714746
super.onOverScrolled(scrollX, scrollY, clampedX, clampedY);
715747
}
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@Override
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public void onChildViewAdded(View parent, View child) {
751+
mContentView = child;
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mContentView.addOnLayoutChangeListener(this);
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}
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@Override
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public void onChildViewRemoved(View parent, View child) {
757+
mContentView.removeOnLayoutChangeListener(this);
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mContentView = null;
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}
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717761
private void enableFpsListener() {
718762
if (isScrollPerfLoggingEnabled()) {
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Assertions.assertNotNull(mFpsListener);
@@ -1237,6 +1281,26 @@ private void setPendingContentOffsets(int x, int y) {
12371281
}
12381282
}
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@Override
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public void onLayoutChange(
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View v,
1287+
int left,
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int top,
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int right,
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int bottom,
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int oldLeft,
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int oldTop,
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int oldRight,
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int oldBottom) {
1295+
if (mContentView == null) {
1296+
return;
1297+
}
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1299+
if (mMaintainVisibleContentPositionHelper != null) {
1300+
mMaintainVisibleContentPositionHelper.updateScrollPosition();
1301+
}
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}
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12401304
@Override
12411305
public FabricViewStateManager getFabricViewStateManager() {
12421306
return mFabricViewStateManager;

‎ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java‎

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Original file line numberDiff line numberDiff line change
@@ -328,6 +328,16 @@ public void setContentOffset(ReactHorizontalScrollView view, ReadableMap value)
328328
}
329329
}
330330

331+
@ReactProp(name = "maintainVisibleContentPosition")
332+
public void setMaintainVisibleContentPosition(ReactHorizontalScrollView view, ReadableMap value) {
333+
if (value != null) {
334+
view.setMaintainVisibleContentPosition(
335+
MaintainVisibleScrollPositionHelper.Config.fromReadableMap(value));
336+
} else {
337+
view.setMaintainVisibleContentPosition(null);
338+
}
339+
}
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331341
@ReactProp(name = ViewProps.POINTER_EVENTS)
332342
public void setPointerEvents(ReactHorizontalScrollView view, @Nullable String pointerEventsStr) {
333343
view.setPointerEvents(PointerEvents.parsePointerEvents(pointerEventsStr));

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