com.facebook.react.views.scroll.ReactScrollViewCommandHelper.java Source code

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Here is the source code for com.facebook.react.views.scroll.ReactScrollViewCommandHelper.java

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/*
 * 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 androidx.annotation.Nullable;
import com.facebook.infer.annotation.Assertions;
import com.facebook.react.bridge.ReadableArray;
import com.facebook.react.common.MapBuilder;
import com.facebook.react.uimanager.PixelUtil;
import java.util.Map;

/**
 * Helper for view managers to handle commands like 'scrollTo'. Shared by {@link
 * ReactScrollViewManager} and {@link ReactHorizontalScrollViewManager}.
 */
public class ReactScrollViewCommandHelper {

    public static final int COMMAND_SCROLL_TO = 1;
    public static final int COMMAND_SCROLL_TO_END = 2;
    public static final int COMMAND_FLASH_SCROLL_INDICATORS = 3;

    public interface ScrollCommandHandler<T> {
        void scrollTo(T scrollView, ScrollToCommandData data);

        void scrollToEnd(T scrollView, ScrollToEndCommandData data);

        void flashScrollIndicators(T scrollView);
    }

    public static class ScrollToCommandData {

        public final int mDestX, mDestY;
        public final boolean mAnimated;

        ScrollToCommandData(int destX, int destY, boolean animated) {
            mDestX = destX;
            mDestY = destY;
            mAnimated = animated;
        }
    }

    public static class ScrollToEndCommandData {

        public final boolean mAnimated;

        ScrollToEndCommandData(boolean animated) {
            mAnimated = animated;
        }
    }

    public static Map<String, Integer> getCommandsMap() {
        return MapBuilder.of("scrollTo", COMMAND_SCROLL_TO, "scrollToEnd", COMMAND_SCROLL_TO_END,
                "flashScrollIndicators", COMMAND_FLASH_SCROLL_INDICATORS);
    }

    public static <T> void receiveCommand(ScrollCommandHandler<T> viewManager, T scrollView, int commandType,
            @Nullable ReadableArray args) {
        Assertions.assertNotNull(viewManager);
        Assertions.assertNotNull(scrollView);
        Assertions.assertNotNull(args);
        switch (commandType) {
        case COMMAND_SCROLL_TO: {
            scrollTo(viewManager, scrollView, args);
            return;
        }
        case COMMAND_SCROLL_TO_END: {
            scrollToEnd(viewManager, scrollView, args);
            return;
        }
        case COMMAND_FLASH_SCROLL_INDICATORS:
            viewManager.flashScrollIndicators(scrollView);
            return;

        default:
            throw new IllegalArgumentException(String.format("Unsupported command %d received by %s.", commandType,
                    viewManager.getClass().getSimpleName()));
        }
    }

    public static <T> void receiveCommand(ScrollCommandHandler<T> viewManager, T scrollView, String commandType,
            @Nullable ReadableArray args) {
        Assertions.assertNotNull(viewManager);
        Assertions.assertNotNull(scrollView);
        Assertions.assertNotNull(args);
        switch (commandType) {
        case "scrollTo": {
            scrollTo(viewManager, scrollView, args);
            return;
        }
        case "scrollToEnd": {
            scrollToEnd(viewManager, scrollView, args);
            return;
        }
        case "flashScrollIndicators":
            viewManager.flashScrollIndicators(scrollView);
            return;

        default:
            throw new IllegalArgumentException(String.format("Unsupported command %s received by %s.", commandType,
                    viewManager.getClass().getSimpleName()));
        }
    }

    private static <T> void scrollTo(ScrollCommandHandler<T> viewManager, T scrollView,
            @Nullable ReadableArray args) {
        int destX = Math.round(PixelUtil.toPixelFromDIP(args.getDouble(0)));
        int destY = Math.round(PixelUtil.toPixelFromDIP(args.getDouble(1)));
        boolean animated = args.getBoolean(2);
        viewManager.scrollTo(scrollView, new ScrollToCommandData(destX, destY, animated));
    }

    private static <T> void scrollToEnd(ScrollCommandHandler<T> viewManager, T scrollView,
            @Nullable ReadableArray args) {
        boolean animated = args.getBoolean(0);
        viewManager.scrollToEnd(scrollView, new ScrollToEndCommandData(animated));
    }
}