android中listview分页加载数据

最新推荐文章于 2021-05-26 17:39:28 发布

原创最新推荐文章于 2021-05-26 17:39:28 发布 · 288 阅读

1 ·

CC 4.0 BY-SA版权

本文介绍了一种在安卓应用中实现ListView分页加载的方法。通过展示具体的XML布局文件和Java代码，详细解释了如何创建自定义适配器、设置加载提示，并通过监听滚动状态来触发数据更新。

在安卓开发中，都会遇到listview刷新的功能，下面就是listview的分页功能

首先3个xml布局

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

items.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="80dp"
    android:orientation="horizontal">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="80dp"
        android:layout_weight="1"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text="Small Text"
        android:background="@color/colorAccent"
        android:id="@+id/textView" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_weight="1"
        android:layout_height="80dp"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text="Small Text"
        android:background="@color/colorPrimary"
        android:textSize="19sp"
        android:id="@+id/textView2" />
</LinearLayout>

loading.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="30dp"
    android:gravity="center"
    android:orientation="horizontal">

    <ProgressBar
        style="?android:attr/progressBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/progressBar" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text=" 正在拼命加载中......"
        android:id="@+id/textView3" />
</LinearLayout>

最后java代码：

首先创建Fruit数据对象然后

public class MainActivity extends AppCompatActivity implements AbsListView.OnScrollListener{
    private ListView listView;
    private List<Fruit> fruits;
    private  MyAdapter adapter;
    private static int DATA_UPDATE = 0X1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView);
        listView.setOnScrollListener(this);
         adapter = new MyAdapter();
        fruits = new ArrayList<>();
        initData();
        View loadbooter = getLayoutInflater().inflate(R.layout.loading,null);
        listView.addFooterView(loadbooter);
        listView.setAdapter(adapter);


    }
    private int indexs=1;
    private void initData() {
        for (int i = 0; i <16 ; i++) {
            Fruit fruit = new Fruit();
            fruit.setName("--name-- "+indexs);
            fruit.setContent("--content-- "+indexs);
            fruits.add(fruit);
            indexs++;
        }
    }

    private int visibleLastIndex;//可显示的最后一条数据索引

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        if(adapter.getCount()==visibleLastIndex&&scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE){
            new LoadThread().start();
        }

    }

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

    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if(msg.what==DATA_UPDATE){
                adapter.notifyDataSetChanged();
            }

        }
    };

    class LoadThread extends Thread{
        @Override
        public void run() {

            initData();
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            handler.sendEmptyMessage(DATA_UPDATE);
        }
    }

    class MyAdapter extends BaseAdapter{

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

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

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            ViewHoder hoder;
            if(convertView==null){
                convertView = getLayoutInflater().inflate(R.layout.items,null);
                hoder = new ViewHoder();
                hoder.name = (TextView)convertView.findViewById(R.id.textView);
                hoder.content = (TextView) convertView.findViewById(R.id.textView2);
                convertView.setTag(hoder);

            }else {
                hoder = (ViewHoder) convertView.getTag();
            }
            Fruit data = fruits.get(position);
            hoder.name.setText(data.getName());
            hoder.content.setText(data.getContent());
            return convertView;
        }
        class ViewHoder{
            TextView name;
            TextView content;
        }
    }
}