上一节我们实现了数据表的载入，可是，当数据表数据非常多时。我们就要考虑数据的分页。这里我们选用了PullToRefreshListView控件，先看一下该控件的说明：
效果图：
正在刷新 刷新后
一、导入Library
下载源代码后（https://github.com/chrisbanes/Android-PullToRefresh），里面有个Libraryproject，加入project到Eclipse中；
另外extras目录还有两个project：PullToRefreshListFragment和PullToRefreshViewPager，因为我们的这个用不到他们的库文件，所以不必导入了。
二、实战
1、新建project，加入Libray库到project中
新建project（try_PullToRefresh）后，右键-》Properties-》Android-》Add 选择上面的Library，然后就是这个样子的
2、重写activity_main.xml
XML内容为：
- <?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:orientation="vertical" >
- <!-- The PullToRefreshListView replaces a standard ListView widget. -->
- <com.handmark.pulltorefresh.library.PullToRefreshListView
- android:id="@+id/pull_refresh_list"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:cacheColorHint="#00000000"
- android:divider="#19000000"
- android:dividerHeight="4dp"
- android:fadingEdge="none"
- android:fastScrollEnabled="false"
- android:footerDividersEnabled="false"
- android:headerDividersEnabled="false"
- android:smoothScrollbar="true" />
- </LinearLayout>
当中中间那一大段<com.handmark.pull………………/>就是相当于ListView控件，用这段来取代原是ListView控件的代码
以下我们看一下详细怎么实现的。
先在数据表中插入数据：
然后看代码。MainActivity.java:
package com.bmob.pagingdemo; import java.util.ArrayList;
import java.util.List; import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
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.TextView;
import android.widget.Toast;
import cn.bmob.v3.Bmob;
import cn.bmob.v3.BmobQuery;
import cn.bmob.v3.listener.FindListener; import com.handmark.pulltorefresh.library.ILoadingLayout;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener2;
import com.handmark.pulltorefresh.library.PullToRefreshListView; public class MainActivity extends Activity { PullToRefreshListView mPullToRefreshView;
private ILoadingLayout loadingLayout;
ListView mMsgListView;
List<TestData> bankCards = new ArrayList<TestData>();// 数据list private static final int STATE_REFRESH = 0;// 下拉刷新
private static final int STATE_MORE = 1;// 载入很多其它 private int limit = 10; // 每页的数据是10条
private int curPage = 0; // 当前页的编号。从0開始 @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); Bmob.initialize(this, "8f3ffb2658d8a3366a70a0b0ca0b71b2");// 初始化
queryData(0, STATE_REFRESH); initListView();// 初始化ListView
} private void initListView() {
mPullToRefreshView = (PullToRefreshListView) findViewById(R.id.list);
loadingLayout = mPullToRefreshView.getLoadingLayoutProxy();
loadingLayout.setLastUpdatedLabel("");
loadingLayout
.setPullLabel(getString(R.string.pull_to_refresh_bottom_pull));// 下拉标签
loadingLayout
.setRefreshingLabel(getString(R.string.pull_to_refresh_bottom_refreshing));// 刷新标签
loadingLayout
.setReleaseLabel(getString(R.string.pull_to_refresh_bottom_release));// 释放标签
// //滑动监听
mPullToRefreshView.setOnScrollListener(new OnScrollListener() { @Override
public void onScrollStateChanged(AbsListView view, int scrollState) { } @Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) { if (firstVisibleItem == 0) {
loadingLayout.setLastUpdatedLabel("");
loadingLayout
.setPullLabel(getString(R.string.pull_to_refresh_top_pull));
loadingLayout
.setRefreshingLabel(getString(R.string.pull_to_refresh_top_refreshing));
loadingLayout
.setReleaseLabel(getString(R.string.pull_to_refresh_top_release));
} else if (firstVisibleItem + visibleItemCount + 1 == totalItemCount) {// 载入完成
loadingLayout.setLastUpdatedLabel("");
loadingLayout
.setPullLabel(getString(R.string.pull_to_refresh_bottom_pull));
loadingLayout
.setRefreshingLabel(getString(R.string.pull_to_refresh_bottom_refreshing));
loadingLayout
.setReleaseLabel(getString(R.string.pull_to_refresh_bottom_release));
}
}
}); // 下拉刷新监听
mPullToRefreshView
.setOnRefreshListener(new OnRefreshListener2<ListView>() { @Override
public void onPullDownToRefresh(
PullToRefreshBase<ListView> refreshView) {
// 下拉刷新(从第一页開始装载数据)
queryData(0, STATE_REFRESH);
} @Override
public void onPullUpToRefresh(
PullToRefreshBase<ListView> refreshView) {
// 上拉载入很多其它(载入下一页数据)
queryData(curPage, STATE_MORE);
}
}); mMsgListView = mPullToRefreshView.getRefreshableView();
// 再设置adapter
mMsgListView.setAdapter(new DeviceListAdapter(this));
} /**
* 分页获取数据
*
* @param page
* 页码
* @param actionType
* ListView的操作类型（下拉刷新、上拉载入很多其它）
*/
private void queryData(final int page, final int actionType) {
Log.i("bmob", "pageN:" + page + " limit:" + limit + " actionType:"
+ actionType); BmobQuery<TestData> query = new BmobQuery<TestData>();
query.setLimit(limit); // 设置每页多少条数据
query.setSkip(page * limit); // 从第几条数据開始，
query.findObjects(this, new FindListener<TestData>() { @Override
public void onSuccess(List<TestData> arg0) {
// TODO Auto-generated method stub if (arg0.size() > 0) {//能载入到数据
if (actionType == STATE_REFRESH) {
// 当是下拉刷新操作时，将当前页的编号重置为0。并把bankCards清空，又一次加入
curPage = 0;
bankCards.clear();
} // 将本次查询的数据加入到bankCards中
for (TestData td : arg0) {
bankCards.add(td);
} // 这里在每次载入完数据后。将当前页码+1。这样在上拉刷新的onPullUpToRefresh方法中就不须要操作curPage了
curPage++;
showToast("第" + (page + 1) + "页数据载入完成");
} else if (actionType == STATE_MORE) {//数据载入完成
showToast("没有很多其它数据了");
} else if (actionType == STATE_REFRESH) {//无数据
showToast("没有数据");
}
mPullToRefreshView.onRefreshComplete();
} @Override
public void onError(int arg0, String arg1) {
// TODO Auto-generated method stub
showToast("查询失败:" + arg1);
mPullToRefreshView.onRefreshComplete();
}
});
} /**
* Adapter
*
* @author Administrator
*
*/
private class DeviceListAdapter extends BaseAdapter { Context context; public DeviceListAdapter(Context context) {
this.context = context;
} @Override
public View getView(final int position, View convertView,
ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) { convertView = LayoutInflater.from(context).inflate(
R.layout.list_item_bankcard, null);
holder = new ViewHolder();
holder.tv_cardNumber = (TextView) convertView
.findViewById(R.id.tv_cardNumber);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
} TestData td = (TestData) getItem(position); holder.tv_cardNumber.setText(td.getName());
return convertView;
} class ViewHolder {
TextView tv_cardNumber;
} @Override
public int getCount() {
return bankCards.size();
} @Override
public Object getItem(int position) {
return bankCards.get(position);
} @Override
public long getItemId(int position) {
return position;
} } private void showToast(String msg) {
Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
} }
TestData.java:
package com.bmob.pagingdemo;
import cn.bmob.v3.BmobObject;
public class TestData extends BmobObject {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
main.xml:
<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" > <com.handmark.pulltorefresh.library.PullToRefreshListView
xmlns:ptr="http://schemas.android.com/apk/res/com.bmob.pagingdemo"
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fadingEdge="none"
android:fastScrollEnabled="false"
android:smoothScrollbar="true"
ptr:ptrMode="both" /> </LinearLayout>
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.bmob.pagingdemo"
android:versionCode="1"
android:versionName="1.0" > <uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="14" /> <uses-permission android:name="android.permission.INTERNET" /> <!-- 同意应用打开网络套接口 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application> </manifest>
执行实例。下拉刷新：
上拉载入，每次载入10条数据：
本实例有个问题，初次进入时不能载入数据。必须下拉才干载入数据，请能找出问题的朋友联系我：291214603。多谢。
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