Android分页加载数据

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
    }

    /**
     * 初始化适配器
     */
    private void initAdapter() {
        ArrayList<String> items = new ArrayList<String>();
        for (int i = 0; i < 16; i++) {
            items.add(String.valueOf(i + 1));
        }
        adapter = new ListViewAdapter(this, items);
    }

    /**
     * 滑动时被调用
     */
    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        this.visibleItemCount = visibleItemCount;
        visibleLastIndex = firstVisibleItem + visibleItemCount - 1;
    }

    /**
     * 滑动状态改变时被调用
     */
    @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);
        }
    }

    /**
     * 点击按钮事件
     * @param view
     */
    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);
    }

    /**
     * 模拟加载数据
     */
    private void loadData() {
        int count = adapter.getCount();
        for (int i = count; i < count + 10; i++) {
            adapter.addItem(String.valueOf(i + 1));
        }
    }

}

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<String> items;
    private LayoutInflater inflater;

    public ListViewAdapter(Context context, List<String> 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;
    }

    /**
     * 添加列表项
     * @param item
     */
    public void addItem(String item) {
        items.add(item);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:paddingLeft="3dp"
    android:paddingRight="3dp">
    <ListView
        android:id="@id/android:list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView
        android:id="@+id/list_item_text"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="aa"
        android:gravity="center"
        android:textSize="20sp"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <Button
        android:id="@+id/loadMoreButton"
        android:visibility="gone"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="load more"
        android:onClick="loadMore"/>
</LinearLayout>