ListView分页加载数据

ListView分页加载数据

FenyeActivity

package com.example.myapplication.fenye;

import androidx.appcompat.app.AppCompatActivity;

import android.app.ListActivity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.AbsListView;
import android.widget.Button;
import android.widget.ListView;

import com.example.myapplication.R;

import java.util.ArrayList;

public class FenyeActivity extends ListActivity implements AbsListView.onScrollListener {
    private ListView listView;
    private int visibleLastIndex = 0;	//最后的可视项索引
    private int visibleItemCount;		// 当前窗口可见项总数
    private ListViewAdapter adapter;
    private View loadMoreView;
    private Button loadMoreButton;
    private Handler handler = new Handler();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fenye);

        loadMoreView = getLayoutInflater().inflate(R.layout.load_more, null);
        loadMoreButton = (Button) loadMoreView.findViewById(R.id.loadMoreButton);

        listView = getListView();				//获取id是list的ListView

        listView.addFooterView(loadMoreView);	//设置列表底部视图

        initAdapter();

        setListAdapter(adapter);				//自动为id是list的ListView设置适配器

        listView.setonScrollListener(this);		//添加滑动监听
    }

    
    private void initAdapter() {
        ArrayList items = new ArrayList();
        for (int i = 0; i < 16; i++) {
            items.add(String.valueOf(i + 1));
        }
        adapter = new ListViewAdapter(this, items);
    }

    
    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        this.visibleItemCount = visibleItemCount;
        visibleLastIndex = firstVisibleItem + visibleItemCount - 1;
    }

    
    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        int itemsLastIndex = adapter.getCount() - 1;	//数据集最后一项的索引
        int lastIndex = itemsLastIndex + 1;				//加上底部的loadMoreView项
        if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE && visibleLastIndex == lastIndex) {
            //如果是自动加载,可以在这里放置异步加载数据的代码
            Log.e("wy", "loading...");

            handler.postDelayed(new Runnable() {
                @Override
                public void run() {

                    loadData();

                    adapter.notifyDataSetChanged();	//数据集变化后,通知adapter
                    listView.setSelection(visibleLastIndex - visibleItemCount + 1);	//设置选中项

                    loadMoreButton.setText("load more");	//恢复按钮文字
                }
            }, 1000);
        }
    }

    
    public void loadMore(View view) {
        loadMoreButton.setText("loading...");	//设置按钮文字loading
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {

                loadData();

                adapter.notifyDataSetChanged();	//数据集变化后,通知adapter
                listView.setSelection(visibleLastIndex - visibleItemCount + 1);	//设置选中项

                loadMoreButton.setText("load more");	//恢复按钮文字
            }
        }, 1000);
    }

    
    private void loadData() {
        int count = adapter.getCount();
        for (int i = count; i < count + 10; i++) {
            adapter.addItem(String.valueOf(i + 1));
        }
    }

}

ListViewAdapter

package com.example.myapplication.fenye;


import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.baseAdapter;
import android.widget.TextView;

import com.example.myapplication.R;

public class ListViewAdapter extends baseAdapter {
    private List items;
    private LayoutInflater inflater;

    public ListViewAdapter(Context context, List items) {
        this.items = items;
        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return items.size();
    }

    @Override
    public Object getItem(int position) {
        return items.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        if (view == null) {
            view = inflater.inflate(R.layout.list_fy_item, null);
        }
        TextView text = (TextView) view.findViewById(R.id.list_item_text);
        if(null!=items){
            text.setText(items.get(position));
        }

        return view;
    }

    
    public void addItem(String item) {
        items.add(item);
    }
}

activity_fenye.xml

list_fy_item.xml

load_more.xml