Question

我一直在寻找一段时间，但无法找到一个解决方案，用网格布局管理器检测回收站视图的滚动结束。使用下面的代码实际上可行，但它适用于线性布局管理器而不适用于网格布局管理器。

/// <reference path="../../typings/chartjs/chart.d.ts" />

import {Directive, ElementRef, Renderer, Input} from 'angular2/core';
@Directive({
    selector: '[chart]'
})
export class ChartDirective {
    constructor(el: ElementRef, renderer: Renderer) {
        //el.nativeElement.style.backgroundColor = 'yellow';
        var data = {
            labels: ["January", "February", "March", "April", "May", "June", "July"],
            datasets: [
                {
                    label: "My First dataset",
                    fillColor: "rgba(220,220,220,0.2)",
                    strokeColor: "rgba(220,220,220,1)",
                    pointColor: "rgba(220,220,220,1)",
                    pointStrokeColor: "#fff",
                    pointHighlightFill: "#fff",
                    pointHighlightStroke: "rgba(220,220,220,1)",
                    data: [65, 59, 80, 81, 56, 55, 40]
                },
                {
                    label: "My Second dataset",
                    fillColor: "rgba(151,187,205,0.2)",
                    strokeColor: "rgba(151,187,205,1)",
                    pointColor: "rgba(151,187,205,1)",
                    pointStrokeColor: "#fff",
                    pointHighlightFill: "#fff",
                    pointHighlightStroke: "rgba(151,187,205,1)",
                    data: [28, 48, 40, 19, 86, 27, 90]
                }
            ]
        };
        var ctx: any = el.nativeElement.getContext("2d");
        var lineChart = new Chart(ctx);
        ////var lineChartOptions = areaChartOptions;
        ////lineChartOptions.datasetFill = false;
        lineChart.Line(data);
    }
}

我的想法是我想为我的应用程序实现加载更多功能，所以我需要检测滚动结束。

编辑：也许问题不是网格视图本身。我使用com.tonicartos.superslim库来获取粘性标题视图。我想知道这可能是问题

Answer 1

向 RecyclerView 添加滚动侦听器，如下所示：

int pastVisiblesItems, visibleItemCount, totalItemCount;  
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                        @Override
                        public void onScrolled(RecyclerView recyclerView,
                                               int dx, int dy) {
                            super.onScrolled(recyclerView, dx, dy);
                            visibleItemCount = layoutManager.getChildCount();
                            totalItemCount = layoutManager.getItemCount();
                            pastVisiblesItems = layoutManager.findFirstVisibleItemPosition();

                           if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
                                //bottom of recyclerview
                          }
                        }
    });

layoutmanager是你的 GridLayoutManager

Answer 2

public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
    public static String TAG = EndlessRecyclerOnScrollListener.class.getSimpleName();

    private int previousTotal = 0; // The total number of items in the dataset after the last load
    private boolean loading = true; // True if we are still waiting for the last set of data to load.
    private int visibleThreshold = 5; // The minimum amount of items to have below your current scroll position before loading more.
    int firstVisibleItem, visibleItemCount, totalItemCount;

    private int currentPage = 1;

    private RecyclerView.LayoutManager mLayoutManager;
    private boolean isUseLinearLayoutManager;
    private boolean isUseGridLayoutManager;

    public EndlessRecyclerOnScrollListener(LinearLayoutManager linearLayoutManager) {
        this.mLayoutManager = linearLayoutManager;
        isUseLinearLayoutManager = true;

    }

    public EndlessRecyclerOnScrollListener(GridLayoutManager gridLayoutManager) {
        this.mLayoutManager = gridLayoutManager;
        isUseGridLayoutManager = true;

    }

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);

        visibleItemCount = recyclerView.getChildCount();
        totalItemCount = mLayoutManager.getItemCount();


        if(isUseLinearLayoutManager && mLayoutManager instanceof LinearLayoutManager){
            firstVisibleItem = ((LinearLayoutManager) mLayoutManager).findFirstVisibleItemPosition();
        }

        if(isUseGridLayoutManager && mLayoutManager instanceof GridLayoutManager){
            firstVisibleItem = ((GridLayoutManager) mLayoutManager).findFirstVisibleItemPosition();
        }

        if (loading) {
            if (totalItemCount > previousTotal) {
                loading = false;
                previousTotal = totalItemCount;
            }
        }
        if (!loading && (totalItemCount - visibleItemCount)
                <= (firstVisibleItem + visibleThreshold)) {
            // End has been reached

            // Do something
            currentPage++;

            onLoadMore(currentPage);

            loading = true;
        }
    }

    public abstract void onLoadMore(int currentPage);

Answer 3

我刚刚直接向Artos先生发送了一封电子邮件，说明了这个问题并得到了答复： “在下一个版本完成之前，它可能无法正常工作。我在我的博客http://www.tonicartos.com/2015/12/superslim-milestone-1_23.html?m=1上写了这篇文章”

使用SuperSLiM库检测RecyclerView的GridLayoutManager滚动结束

3 个答案: