简单模拟ListView自动加载。
java代码：
package com.example.testlistview;
import java.util.ArrayList;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends Activity {
private static final String tag = MainActivity.class.getSimpleName();
ArrayAdapter<CharSequence> aa = null;
private int state = 0; // 0:等待, 1:正在提取数据并更新
ListView lview = null;
View footview = null;
ArrayList<String> buff = new ArrayList<String>();
private int count = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.init();
Log.w(tag, "init: state value[" + state + "]");
}
private void init() {
ArrayList<CharSequence> data = new ArrayList<CharSequence>();
for (int k = 0; k < 15; k++) {
data.add("hello - " + k);
}
lview = (ListView) this.findViewById(R.id.listview);
aa = new ArrayAdapter<CharSequence>(this,
android.R.layout.simple_list_item_1, data);
LayoutInflater ll = this.getLayoutInflater();
footview = ll.inflate(R.layout.lfootview, null);
lview.addFooterView(footview);
final MyHandler myHandler = new MyHandler();
lview.setOnScrollListener(new OnScrollListener() {
private boolean state_idle = false;
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (!this.state_idle)
return;
// Log.w(tag,
// "firstVisibleItem["+firstVisibleItem+"], visibleItemCount["+visibleItemCount+"], totalItemCount["+totalItemCount+"]");
if (firstVisibleItem == 0
|| (firstVisibleItem + visibleItemCount) != totalItemCount) {
return;
}
Log.w(tag, "提取数据 ..., count[" + count + "]");
state = 1;
MyThread mth = new MyThread(myHandler);
Thread th = new Thread(mth);
th.start();
}
public void onScrollStateChanged(AbsListView view, int scrollState) {
Log.w(tag, "scroll_state[" + scrollState + "], state[" + state
+ "]");
if (OnScrollListener.SCROLL_STATE_IDLE != scrollState) {
return;
}
if (0 != state)
return;
this.state_idle = true;
}
});
lview.setAdapter(aa);
}
public void updateData() {
Log.w(tag, "更新数据 ...");
Log.w(tag, "删除多余数据 .");
while (aa.getCount() > 45) {
aa.remove(aa.getItem(0));
}
for (int k = 0; k < buff.size(); k++) {
aa.add(buff.get(k));
}
this.aa.notifyDataSetChanged();
state = 0;
Log.w(tag, "更新数据完毕 .");
count++;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
class MyThread implements java.lang.Runnable {
private MyHandler handler;
public MyThread(MyHandler handler) {
this.handler = handler;
}
public void run() {
for (int k = 0; k < 5; k++) {
String value = "hello - " + (aa.getCount() + 1);
buff.add(value);
Log.w(tag, "value[" + value + "]");
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Message msg = Message.obtain();
Bundle b = new Bundle();
b.putInt("result", 200);
msg.setData(b);
handler.sendMessage(msg);
Log.w(tag, "消息发送完毕 .");
}
}
class MyHandler extends Handler {
@Override
public void handleMessage(Message msg) {
int result = msg.getData().getInt("result");
Log.w(tag, "result:" + result);
if (200 == result) {
MainActivity.this.updateData();
}
super.handleMessage(msg);
}
}
}
二、布局文件：
1、activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world"
android:layout_gravity="center"
tools:context=".MainActivity" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
>
<ListView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/listview"
android:background="@android:color/transparent"
></ListView>
</RelativeLayout>
</LinearLayout>
2、lfootview.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="100dp"
>
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
style="?android:attr/progressBarStyleInverse"
/>
</RelativeLayout>
