Java tutorial
/* * Copyright (c) Facebook, Inc. and its affiliates. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. */ package com.facebook.react.views.scroll; import android.graphics.Color; import android.util.DisplayMetrics; import androidx.annotation.Nullable; import androidx.core.view.ViewCompat; import com.facebook.react.bridge.ReadableArray; import com.facebook.react.module.annotations.ReactModule; import com.facebook.react.uimanager.DisplayMetricsHolder; import com.facebook.react.uimanager.PixelUtil; import com.facebook.react.uimanager.ReactClippingViewGroupHelper; import com.facebook.react.uimanager.Spacing; import com.facebook.react.uimanager.ThemedReactContext; import com.facebook.react.uimanager.ViewGroupManager; import com.facebook.react.uimanager.ViewProps; import com.facebook.react.uimanager.annotations.ReactProp; import com.facebook.react.uimanager.annotations.ReactPropGroup; import com.facebook.yoga.YogaConstants; import java.util.ArrayList; import java.util.List; /** * View manager for {@link ReactHorizontalScrollView} components. * * <p>Note that {@link ReactScrollView} and {@link ReactHorizontalScrollView} are exposed to JS as a * single ScrollView component, configured via the {@code horizontal} boolean property. */ @ReactModule(name = ReactHorizontalScrollViewManager.REACT_CLASS) public class ReactHorizontalScrollViewManager extends ViewGroupManager<ReactHorizontalScrollView> implements ReactScrollViewCommandHelper.ScrollCommandHandler<ReactHorizontalScrollView> { public static final String REACT_CLASS = "AndroidHorizontalScrollView"; private static final int[] SPACING_TYPES = { Spacing.ALL, Spacing.LEFT, Spacing.RIGHT, Spacing.TOP, Spacing.BOTTOM, }; private @Nullable FpsListener mFpsListener = null; public ReactHorizontalScrollViewManager() { this(null); } public ReactHorizontalScrollViewManager(@Nullable FpsListener fpsListener) { mFpsListener = fpsListener; } @Override public String getName() { return REACT_CLASS; } @Override public ReactHorizontalScrollView createViewInstance(ThemedReactContext context) { return new ReactHorizontalScrollView(context, mFpsListener); } @ReactProp(name = "scrollEnabled", defaultBoolean = true) public void setScrollEnabled(ReactHorizontalScrollView view, boolean value) { view.setScrollEnabled(value); } @ReactProp(name = "showsHorizontalScrollIndicator") public void setShowsHorizontalScrollIndicator(ReactHorizontalScrollView view, boolean value) { view.setHorizontalScrollBarEnabled(value); } @ReactProp(name = "decelerationRate") public void setDecelerationRate(ReactHorizontalScrollView view, float decelerationRate) { view.setDecelerationRate(decelerationRate); } @ReactProp(name = "disableIntervalMomentum") public void setDisableIntervalMomentum(ReactHorizontalScrollView view, boolean disbaleIntervalMomentum) { view.setDisableIntervalMomentum(disbaleIntervalMomentum); } @ReactProp(name = "snapToInterval") public void setSnapToInterval(ReactHorizontalScrollView view, float snapToInterval) { // snapToInterval needs to be exposed as a float because of the Javascript interface. DisplayMetrics screenDisplayMetrics = DisplayMetricsHolder.getScreenDisplayMetrics(); view.setSnapInterval((int) (snapToInterval * screenDisplayMetrics.density)); } @ReactProp(name = "snapToOffsets") public void setSnapToOffsets(ReactHorizontalScrollView view, @Nullable ReadableArray snapToOffsets) { DisplayMetrics screenDisplayMetrics = DisplayMetricsHolder.getScreenDisplayMetrics(); List<Integer> offsets = new ArrayList<Integer>(); for (int i = 0; i < snapToOffsets.size(); i++) { offsets.add((int) (snapToOffsets.getDouble(i) * screenDisplayMetrics.density)); } view.setSnapOffsets(offsets); } @ReactProp(name = "snapToStart") public void setSnapToStart(ReactHorizontalScrollView view, boolean snapToStart) { view.setSnapToStart(snapToStart); } @ReactProp(name = "snapToEnd") public void setSnapToEnd(ReactHorizontalScrollView view, boolean snapToEnd) { view.setSnapToEnd(snapToEnd); } @ReactProp(name = ReactClippingViewGroupHelper.PROP_REMOVE_CLIPPED_SUBVIEWS) public void setRemoveClippedSubviews(ReactHorizontalScrollView view, boolean removeClippedSubviews) { view.setRemoveClippedSubviews(removeClippedSubviews); } /** * Computing momentum events is potentially expensive since we post a runnable on the UI thread to * see when it is done. We only do that if {@param sendMomentumEvents} is set to true. This is * handled automatically in js by checking if there is a listener on the momentum events. * * @param view * @param sendMomentumEvents */ @ReactProp(name = "sendMomentumEvents") public void setSendMomentumEvents(ReactHorizontalScrollView view, boolean sendMomentumEvents) { view.setSendMomentumEvents(sendMomentumEvents); } /** * Tag used for logging scroll performance on this scroll view. Will force momentum events to be * turned on (see setSendMomentumEvents). * * @param view * @param scrollPerfTag */ @ReactProp(name = "scrollPerfTag") public void setScrollPerfTag(ReactHorizontalScrollView view, String scrollPerfTag) { view.setScrollPerfTag(scrollPerfTag); } @ReactProp(name = "pagingEnabled") public void setPagingEnabled(ReactHorizontalScrollView view, boolean pagingEnabled) { view.setPagingEnabled(pagingEnabled); } /** Controls overScroll behaviour */ @ReactProp(name = "overScrollMode") public void setOverScrollMode(ReactHorizontalScrollView view, String value) { view.setOverScrollMode(ReactScrollViewHelper.parseOverScrollMode(value)); } @ReactProp(name = "nestedScrollEnabled") public void setNestedScrollEnabled(ReactHorizontalScrollView view, boolean value) { ViewCompat.setNestedScrollingEnabled(view, value); } @Override public void receiveCommand(ReactHorizontalScrollView scrollView, int commandId, @Nullable ReadableArray args) { ReactScrollViewCommandHelper.receiveCommand(this, scrollView, commandId, args); } @Override public void receiveCommand(ReactHorizontalScrollView scrollView, String commandId, @Nullable ReadableArray args) { ReactScrollViewCommandHelper.receiveCommand(this, scrollView, commandId, args); } @Override public void flashScrollIndicators(ReactHorizontalScrollView scrollView) { scrollView.flashScrollIndicators(); } @Override public void scrollTo(ReactHorizontalScrollView scrollView, ReactScrollViewCommandHelper.ScrollToCommandData data) { if (data.mAnimated) { scrollView.smoothScrollTo(data.mDestX, data.mDestY); } else { scrollView.scrollTo(data.mDestX, data.mDestY); } } @Override public void scrollToEnd(ReactHorizontalScrollView scrollView, ReactScrollViewCommandHelper.ScrollToEndCommandData data) { // ScrollView always has one child - the scrollable area int right = scrollView.getChildAt(0).getWidth() + scrollView.getPaddingRight(); if (data.mAnimated) { scrollView.smoothScrollTo(right, scrollView.getScrollY()); } else { scrollView.scrollTo(right, scrollView.getScrollY()); } } /** * When set, fills the rest of the scrollview with a color to avoid setting a background and * creating unnecessary overdraw. * * @param view * @param color */ @ReactProp(name = "endFillColor", defaultInt = Color.TRANSPARENT, customType = "Color") public void setBottomFillColor(ReactHorizontalScrollView view, int color) { view.setEndFillColor(color); } @ReactPropGroup(names = { ViewProps.BORDER_RADIUS, ViewProps.BORDER_TOP_LEFT_RADIUS, ViewProps.BORDER_TOP_RIGHT_RADIUS, ViewProps.BORDER_BOTTOM_RIGHT_RADIUS, ViewProps.BORDER_BOTTOM_LEFT_RADIUS }, defaultFloat = YogaConstants.UNDEFINED) public void setBorderRadius(ReactHorizontalScrollView view, int index, float borderRadius) { if (!YogaConstants.isUndefined(borderRadius)) { borderRadius = PixelUtil.toPixelFromDIP(borderRadius); } if (index == 0) { view.setBorderRadius(borderRadius); } else { view.setBorderRadius(borderRadius, index - 1); } } @ReactProp(name = "borderStyle") public void setBorderStyle(ReactHorizontalScrollView view, @Nullable String borderStyle) { view.setBorderStyle(borderStyle); } @ReactPropGroup(names = { ViewProps.BORDER_WIDTH, ViewProps.BORDER_LEFT_WIDTH, ViewProps.BORDER_RIGHT_WIDTH, ViewProps.BORDER_TOP_WIDTH, ViewProps.BORDER_BOTTOM_WIDTH, }, defaultFloat = YogaConstants.UNDEFINED) public void setBorderWidth(ReactHorizontalScrollView view, int index, float width) { if (!YogaConstants.isUndefined(width)) { width = PixelUtil.toPixelFromDIP(width); } view.setBorderWidth(SPACING_TYPES[index], width); } @ReactPropGroup(names = { "borderColor", "borderLeftColor", "borderRightColor", "borderTopColor", "borderBottomColor" }, customType = "Color") public void setBorderColor(ReactHorizontalScrollView view, int index, Integer color) { float rgbComponent = color == null ? YogaConstants.UNDEFINED : (float) ((int) color & 0x00FFFFFF); float alphaComponent = color == null ? YogaConstants.UNDEFINED : (float) ((int) color >>> 24); view.setBorderColor(SPACING_TYPES[index], rgbComponent, alphaComponent); } @ReactProp(name = "overflow") public void setOverflow(ReactHorizontalScrollView view, @Nullable String overflow) { view.setOverflow(overflow); } @ReactProp(name = "persistentScrollbar") public void setPersistentScrollbar(ReactHorizontalScrollView view, boolean value) { view.setScrollbarFadingEnabled(!value); } @ReactProp(name = "fadingEdgeLength") public void setFadingEdgeLength(ReactHorizontalScrollView view, int value) { if (value > 0) { view.setHorizontalFadingEdgeEnabled(true); view.setFadingEdgeLength(value); } else { view.setHorizontalFadingEdgeEnabled(false); view.setFadingEdgeLength(0); } } }