Question

本机脚本rad-list-view无法检测是向上滑动还是向下滑动项目列表。

通过使用本机脚本滑动事件

，一个将获得4个左，右，上和下值，即1,2,4,8。但是滑动操作不适用于rad-list-view。

        <lv:RadListView pullToRefresh="true" pullToRefreshInitiated="{{onPullToRefreshInitiated}}"
        scrolled="onScrolled" scrollOffset="scrollOffset" scrollStarted="onScrollStarted" scrollEnded="onScrollEnded"
        id="id_content" row="1" items="{{ source }}" loaded="onLoaded" backgroundColor="transparent"
        itemLoading="onItemLoading" itemTap="onItemTap">

            <lv:RadListView.itemTemplate>
                <StackLayout orientation="vertical" 
                backgroundColor="antiquewhite" margin="5" padding="10" borderWidth="1">

                    <Label fontSize="20" text="{{ name }}"/>
                    <Label fontSize="14" text="{{ name }}"/>

                </StackLayout>
            </lv:RadListView.itemTemplate>

            <lv:RadListView.listViewLayout>
                <lv:ListViewStaggeredLayout scrollDirection="Vertical" spanCount="2"/>
            </lv:RadListView.listViewLayout>

            <lv:RadListView.pullToRefreshStyle>
                <lv:PullToRefreshStyle indicatorColor="red" indicatorBackgroundColor="antiquewhite"/>
            </lv:RadListView.pullToRefreshStyle>

        </lv:RadListView>

    </GridLayout>

如何在radlistview上检测向上或向下滑动事件。

Answer 1

比较scrollOffset和scrollStarted事件之间的scrollEnded，如果开始位置小于结束位置，则用户已向上滚动，否则向下滚动。

let lastOffset;

export function onScrollStarted(args) {
    lastOffset = args.object.getScrollOffset();
}

export function onScrollEnded(args) {
    let currentOffset = args.object.getScrollOffset();
    console.log(currentOffset < lastOffset ? "Up" : "Down");
    lastOffset = currentOffset;
}

Playground Sample

如何检测在radlistview中是向上滚动还是向下滚动

1 个答案: