Android ListView分页加载数据 Android之ListView分页加载数据功能实现代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
 tools:context="com.company.listviewdeepknow.MainActivity">

 <ListView
  android:id="@+id/mList"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
 </ListView>
</RelativeLayout>

<?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="70dp"
 android:gravity="center"
 android:orientation="horizontal">

 <ProgressBar
  android:id="@+id/progressBar"
  style="?android:attr/progressBarStyleSmall"
  android:layout_width="45dp"
  android:layout_height="45dp" />

 <TextView
  android:id="@+id/mLoad"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="加载更多..."
  android:textSize="20sp" />
</LinearLayout>

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

 <TextView
  android:id="@+id/mTv1"
  android:layout_width="100dp"
  android:layout_height="100dp"
  android:textSize="20sp" />

 <TextView
  android:id="@+id/mTv2"
  android:layout_width="100dp"
  android:layout_height="100dp"
  android:layout_alignParentRight="true"
  android:textSize="20sp" />
</RelativeLayout>

public class MainActivity extends AppCompatActivity implements MyOnScrollListener.OnloadDataListener {
 //ListView展示的数据项
 private List<Student> data;
 //ListView控件
 private ListView mList;

 //自定义适配器
 MyAdapter adapter;

 //底部加载更多布局
 View footer;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  //首先加载默认数据，这里设置为10条
  getData();
  //显示到ListView上
  showListView(data);
  //自定义的滚动监听事件
  MyOnScrollListener onScrollListener = new MyOnScrollListener(footer, data);
  //设置接口回调
  onScrollListener.setOnLoadDataListener(this);
  //设置ListView的滚动监听事件
  mList.setOnScrollListener(onScrollListener);
 }

 /**
  * 初始化ListView数据，默认设置为10条
  */
 private void getData() {
  data = new ArrayList<>();
  Student stu = null;
  for (int i = 0; i < 10; i++) {
   stu = new Student();
   stu.setName("姓名" + i);
   stu.setSex(i % 2 == 0 ? "男" : "女");
   data.add(stu);
  }
 }

 /**
  * 将数据加载到ListView上
  *
  * @param data
  */
 private void showListView(List<Student> data) {
  //首先判断适配器是否为空，首次运行肯定是为空的
  if (adapter == null) {
   //查到ListView控件
   mList = (ListView) findViewById(R.id.mList);
   //将底部加载一个加载更多的布局
   footer = LayoutInflater.from(this).inflate(R.layout.foot_boot, null);
   //初始状态为隐藏
   footer.setVisibility(View.GONE);
   //加入到ListView的底部
   mList.addFooterView(footer);
   //创建adpter数据
   adapter = new MyAdapter(data);
   //设置adapter
   mList.setAdapter(adapter);
  } else {
   //不为空，则刷新数据
   this.data = data;
   //提醒ListView重新更新数据
   adapter.notifyDataSetChanged();
  }
 }


 @Override
 public void onLoadData(List<Student> data) {
  //加载数据完成后，展示数据到ListView
  showListView(data);
 }
}

public class MyOnScrollListener implements AbsListView.OnScrollListener {

 //ListView总共显示多少条
 private int totalItemCount;

 //ListView最后的item项
 private int lastItem;

 //用于判断当前是否在加载
 private boolean isLoading;

 //底部加载更多布局
 private View footer;

 //接口回调的实例
 private OnloadDataListener listener;

 //数据
 private List<Student> data;

 public MyOnScrollListener(View footer, List<Student> data) {
  this.footer = footer;
  this.data = data;
 }
 //设置接口回调的实例
 public void setOnLoadDataListener(OnloadDataListener listener) {
  this.listener = listener;
 }

 /**
  * 滑动状态变化
  *
  * @param view
  * @param scrollState 1 SCROLL_STATE_TOUCH_SCROLL是拖动 2 SCROLL_STATE_FLING是惯性滑动 0SCROLL_STATE_IDLE是停止 , 只有当在不同状态间切换的时候才会执行
  */
 @Override
 public void onScrollStateChanged(AbsListView view, int scrollState) {
  //如果数据没有加载，并且滑动状态是停止的，而且到达了最后一个item项
  if (!isLoading && lastItem == totalItemCount && scrollState == SCROLL_STATE_IDLE) {
   //显示加载更多
   footer.setVisibility(View.VISIBLE);
   Handler handler = new Handler();
   //模拟一个延迟两秒的刷新功能
   handler.postDelayed(new Runnable() {
    @Override
    public void run() {
     if (listener != null) {
      //开始加载更多数据
      loadMoreData();
      //回调设置ListView的数据
      listener.onLoadData(data);
      //加载完成后操作什么
      loadComplete();
     }
    }
   }, 2000);
  }
 }

 /**
  * 当加载数据完成后，设置加载标志为false表示没有加载数据了
  * 并且设置底部加载更多为隐藏
  */
 private void loadComplete() {
  isLoading = false;
  footer.setVisibility(View.GONE);

 }

 /**
  * 开始加载更多新数据，这里每次只更新三条数据
  */
 private void loadMoreData() {
  isLoading = true;
  Student stu = null;
  for (int i = 0; i < 3; i++) {
   stu = new Student();
   stu.setName("新名字" + i);
   stu.setSex("新性别" + i);
   data.add(stu);
  }
 }


 /**
  * 监听可见界面的情况
  *
  * @param view    ListView
  * @param firstVisibleItem 第一个可见的 item 的索引
  * @param visibleItemCount 可以显示的 item的条数
  * @param totalItemCount 总共有多少个 item
  */
 @Override
 public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
  //当可见界面的第一个item + 当前界面多有可见的界面个数就可以得到最后一个item项了
  lastItem = firstVisibleItem + visibleItemCount;
  //总listView的item个数
  this.totalItemCount = totalItemCount;
 }
 //回调接口
 public interface OnloadDataListener {
  void onLoadData(List<Student> data);
 }
}

public class MyAdapter extends MyBaseAdapter<Student> {

 public MyAdapter(List<Student> data) {
  super(data);
 }

 @Override
 public void setData(ViewHolder holder, Student t) {
  holder.setText(R.id.mTv1, t.getName()).setText(R.id.mTv2, t.getSex());

 }

}

public abstract class MyBaseAdapter<T> extends BaseAdapter {
 protected List<T> data;
 public MyBaseAdapter(List<T> data){
  this.data = data;
 }
 @Override
 public int getCount() {
  return data == null ? 0 : data.size();
 }

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

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

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  ViewHolder holder = ViewHolder.getHolder(convertView,parent,position, R.layout.list_item);
  setData(holder,data.get(position));
  return holder.getConvertView();
 }
 public abstract void setData(ViewHolder holder,T t);
}

public class ViewHolder {
 private int position;
 private SparseArray<View> array;
 private View convertView;
 private Context context;

 private ViewHolder(ViewGroup parent, int position, int layout) {
  this.position = position;
  this.context = parent.getContext();
  convertView = LayoutInflater.from(parent.getContext()).inflate(layout, null);
  convertView.setTag(this);
  array = new SparseArray<>();
 }

 public static ViewHolder getHolder(View convertView, ViewGroup parent, int position, int layout) {
  if (convertView == null) {
   return new ViewHolder(parent, position, layout);
  } else {
   ViewHolder holder = (ViewHolder) convertView.getTag();
   holder.position = position;
   return holder;
  }
 }

 public <T extends View> T getView(int viewId) {
  View view = array.get(viewId);
  if (view == null) {
   view = convertView.findViewById(viewId);
   array.put(viewId, view);
  }
  return (T) view;
 }

 public View getConvertView() {
  return convertView;
 }

 public ViewHolder setText(int viewId, String data) {
  TextView tv = getView(viewId);
  tv.setText(data);
  return this;
 }

public class Student {
 private String name;
 private String sex;

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String getSex() {
  return sex;
 }

 public void setSex(String sex) {
  this.sex = sex;
 }
}