安卓无尽列表 [英] Android Endless List

问题描述

如何创建一个列表，当您到达列表末尾时，我会收到通知，以便我可以加载更多项目?

How can I create a list where when you reach the end of the list I am notified so I can load more items?

推荐答案

一种解决方案是实现一个 OnScrollListener 并对 ListAdapter 在其 onScroll 方法中处于方便的状态.

One solution is to implement an OnScrollListener and make changes (like adding items, etc.) to the ListAdapter at a convenient state in its onScroll method.

下面的 ListActivity 显示了一个整数列表，从 40 开始，当用户滚动到列表末尾时添加项目.

The following ListActivity shows a list of integers, starting with 40, adding items when the user scrolls to the end of the list.

public class Test extends ListActivity implements OnScrollListener {

    Aleph0 adapter = new Aleph0();

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setListAdapter(adapter); 
        getListView().setOnScrollListener(this);
    }

    public void onScroll(AbsListView view,
        int firstVisible, int visibleCount, int totalCount) {

        boolean loadMore = /* maybe add a padding */
            firstVisible + visibleCount >= totalCount;

        if(loadMore) {
            adapter.count += visibleCount; // or any other amount
            adapter.notifyDataSetChanged();
        }
    }

    public void onScrollStateChanged(AbsListView v, int s) { }    

    class Aleph0 extends BaseAdapter {
        int count = 40; /* starting amount */

        public int getCount() { return count; }
        public Object getItem(int pos) { return pos; }
        public long getItemId(int pos) { return pos; }

        public View getView(int pos, View v, ViewGroup p) {
                TextView view = new TextView(Test.this);
                view.setText("entry " + pos);
                return view;
        }
    }
}

对于长时间运行的操作(例如加载网络数据)，您显然应该使用单独的线程，并且可能希望指示最后一个列表项的进度(例如市场或 gmail 应用程序所做的).

You should obviously use separate threads for long running actions (like loading web-data) and might want to indicate progress in the last list item (like the market or gmail apps do).

这篇关于安卓无尽列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！