Android ListView 滚动翻页效果

前面说过了ListView的下拉刷新效果，有些时候我们需要让ListView在滑动到最底部时，自动去向服务器请求下一页数据。这时候就需要监听的ListView的滑动状态了。

mListView.setOnScrollListener(OnScrollListener l);

OnScrollListener 内部有3个常量来记录ListView的滚动状态

int SCROLL_STATE_FLING                                       The user had previously been scrolling using touch and had performed a fling. 
int SCROLL_STATE_IDLE                                          The view is not scrolling. 
int SCROLL_STATE_TOUCH_SCROLL                  The user is scrolling using touch, and their finger is still on the screen  

知道这些常量代表的含义，我们就可以很轻松的实现 滚动翻页的效果了。

footer_more.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:gravity="center_horizontal"    android:orientation="horizontal"    android:padding="15dp" >    <ProgressBar        android:id="@+id/pb_load_progress"        style="@android:style/Widget.ProgressBar.Small.Inverse"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:gravity="center"        android:indeterminate="true">    </ProgressBar>    <TextView        android:id="@+id/tv_load_more"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginLeft="10.0dp"        android:gravity="center"        android:text="@string/load_more_data"        android:textColor="@color/black" >    </TextView></LinearLayout>

activity_main.xml

<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=".MainActivity" >    <TextView        android:id="@+id/tv_title"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerHorizontal="true"        android:layout_marginTop="5dp"        android:text="@string/load_more"        android:textSize="15sp" />    <ListView        android:id="@+id/mListView"        android:layout_below="@id/tv_title"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:cacheColorHint="@android:color/transparent" /></RelativeLayout>

list_item.xml

<?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="wrap_content" >    <ImageView        android:id="@+id/iv_icon"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:contentDescription="@string/app_name"        android:src="@drawable/ic_launcher" />    <TextView        android:id="@+id/tv_title"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_toRightOf="@id/iv_icon"        android:textSize="18sp"        android:textColor="@color/black"/>        <TextView        android:id="@+id/tv_content"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_toRightOf="@id/iv_icon"        android:layout_below="@id/tv_title"        android:layout_marginTop="5dp"        android:textSize="15sp"        android:textColor="@color/black"/></RelativeLayout>

package com.example.loadmore;import java.util.ArrayList;import java.util.List;import com.example.loadmore.entity.DataNews;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.os.Handler;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.AbsListView.OnScrollListener;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.ProgressBar;import android.widget.TextView;public class MainActivity extends Activity implements OnScrollListener {private static final int LOAD_DATA_FINISH = 1;private static final String TAG = MainActivity.class.getName();private List<DataNews> dataList = new ArrayList<DataNews>();private Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {switch (msg.what) {case LOAD_DATA_FINISH:tv_load_more.setText(R.string.load_more_data);pb_load_progress.setVisibility(View.GONE);if(mAdapter!=null){mAdapter.notifyDataSetChanged();}break;default:break;}};};private int startIndex = 0;private int requestSize = 10;private ListView mListView;private View moreView;private DataAdapter mAdapter;private int lastItem;private TextView tv_load_more;private ProgressBar pb_load_progress;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);findView();setListener();}private void findView() {LayoutInflater inflater = LayoutInflater.from(getApplicationContext());moreView = inflater.inflate(R.layout.footer_more, null);tv_load_more = (TextView) moreView.findViewById(R.id.tv_load_more);pb_load_progress = (ProgressBar) moreView.findViewById(R.id.pb_load_progress);mListView = (ListView) findViewById(R.id.mListView);for (int i = 0; i < 10; i++) {DataNews dn = new DataNews();dn.setTitle("第 " + i + " 行标题");dn.setContent("" + i + " 行内容");dataList.add(dn);}mListView.addFooterView(moreView);mAdapter = new DataAdapter(getApplicationContext());mListView.setAdapter(mAdapter);}private void setListener() {mListView.setOnScrollListener(this);}@Overridepublic void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {lastItem = firstVisibleItem + visibleItemCount - 1;// Log.i(TAG,// "firstVisibleItem:"+firstVisibleItem+"visibleItemCount:"+visibleItemCount+" lastItem:"+lastItem);}@Overridepublic void onScrollStateChanged(AbsListView view, int scrollState) {if (lastItem == mAdapter.getCount()&& scrollState == OnScrollListener.SCROLL_STATE_IDLE) {Log.e(TAG, "load more");startIndex += requestSize;loadMoreData();}}private void loadMoreData() {tv_load_more.setText(R.string.loading_data);pb_load_progress.setVisibility(View.VISIBLE);new Thread(){public void run() {if (startIndex + requestSize <50) {for (int i = startIndex; i < startIndex + requestSize; i++) {DataNews dn = new DataNews();dn.setTitle("增加 第 " + i + " 行标题");dn.setContent("增加 第 " + i + " 行内容");dataList.add(dn);}try {Thread.sleep(3000);} catch (InterruptedException e) {e.printStackTrace();}handler.sendEmptyMessage(LOAD_DATA_FINISH);}else{handler.postDelayed(new Runnable() {@Overridepublic void run() {tv_load_more.setText(R.string.no_more_data);pb_load_progress.setVisibility(View.GONE);}}, 1000);}};}.start();}private class DataAdapter extends BaseAdapter {private Context ctx;private LayoutInflater inflater;public DataAdapter(Context ctx) {this.ctx = ctx;inflater = LayoutInflater.from(ctx);}@Overridepublic int getCount() {return dataList == null ? 0 : dataList.size();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn dataList.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder holder;if (convertView == null) {convertView = inflater.inflate(R.layout.list_item, null);holder = new ViewHolder();holder.tv_title = (TextView) convertView.findViewById(R.id.tv_title);holder.tv_content = (TextView) convertView.findViewById(R.id.tv_content);convertView.setTag(holder);} else {holder = (ViewHolder) convertView.getTag();}DataNews dn = dataList.get(position);holder.tv_title.setText(dn.getTitle());holder.tv_content.setText(dn.getContent());return convertView;}}static class ViewHolder {public TextView tv_title;public TextView tv_content;}}

运行效果截图

正常状态时

滚动到底部时

没有更多数据时