android ListView分页加载

android ListView分页加载

本文主要参考文章：Android数据分批加载-滑动到底部自动加载列表
网页里面一般就是有分页控件，然后分别给出pagesize和nowpagenumber就ok了，但是移动端的手机上不能这样做，分页就是通过一个简答的滑动实现的，例如：微信的朋友圈之类的。好了，下面上货==>
1、布局文件：

<?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.example.administrator.datapageload.MainActivity">

<TextView
android:id="@+id/text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:gravity="center"
android:text="列表分页加载"
android:textColor="#f00"
android:textSize="50sp" />

<ListView
android:layout_width="match_parent"
android:id="@+id/listview"
android:layout_height="match_parent"
android:layout_below="@+id/text"></ListView>
</RelativeLayout>

2、需要的一些资源（list列表样式和footer底部样式）：



footer.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="match_parent"
android:gravity="center"
android:orientation="horizontal">

<ProgressBar
style="@android:style/Widget.ProgressBar.Small"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:text="加载中..."/>
</LinearLayout>

simple_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/simple_list_text"
android:textColor="#0f0"
android:textSize="30sp"/>
</LinearLayout>

3、MainActivity.java

package com.example.administrator.datapageload;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AbsListView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
private final String TAG = MainActivity.class.getSimpleName();
private ListView listView;
private View footer;

private List<String> data = new ArrayList<String>();
ArrayAdapter<String> adapter;
private boolean loadFinishFlag;
private int startIndex;
private int endIndex;
private final int pageSize = 20;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) this.findViewById(R.id.listview);
footer = getLayoutInflater().inflate(R.layout.footer, null);

loadFinishFlag = true;
startIndex = 0;
endIndex = pageSize;
data.addAll(getDataService(startIndex, endIndex));
adapter = new ArrayAdapter<String>(this, R.layout.simple_list, R.id.simple_list_text, data);
listView.setAdapter(adapter);
listView.addFooterView(footer);
listView.setOnScrollListener(new ScrollListener());
listView.removeFooterView(footer);
}

/**
* 模拟加载数据
*
* @param from
* @param to
* @return
*/
public List<String> getDataService(int from, int to) {
List<String> resList = new ArrayList<>();
for (int i = from; i < to; i++) {
resList.add("测试数据" + i);
}
return resList;
}

public final class ScrollListener implements AbsListView.OnScrollListener {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
Log.i(TAG, "---->" + scrollState);
switch (scrollState) {
case SCROLL_STATE_IDLE:
break;
case SCROLL_STATE_TOUCH_SCROLL:
break;
case SCROLL_STATE_FLING:
break;
}
}

@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
//获取屏幕最后Item的ID
int lastVisibleItem = listView.getLastVisiblePosition();
if (lastVisibleItem + 1 == totalItemCount) {
if (loadFinishFlag) {
//标志位，防止多次加载
loadFinishFlag = false;
listView.addFooterView(footer);
//开线程加载数据
new Thread() {
@Override
public void run() {
super.run();
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
startIndex += pageSize;
endIndex += pageSize;
Message message = handler.obtainMessage(0x123, getDataService(startIndex, endIndex));
message.sendToTarget();
}
}.start();
}
}
}
}

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
if (msg.what == 0x123) {
data.addAll((List<String>) msg.obj);
adapter.notifyDataSetChanged();
listView.removeFooterView(footer);
loadFinishFlag = true;
}
}
};
}

4、总结一下，就是监听滑动时间，发现滑动到底端的时候，进行继续加载。当然，加载采用线程和Handler的方式。需要注意的是加入标志位，如果不加，会加载很多次。

下面是运行结果：



在加载20条：



再加载20条：



最后附上项目代码：点我下载，不要你的积分哦！！！