Android ListView滑动加载

项目结构如图所示：



项目主要包括一个activity和三个xml页面布局，代码如下：

MainActivity.java

import android.app.ListActivity;
import android.os.Bundle;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;

public class MainActivity extends ListActivity implements OnScrollListener {

private ListView listView;
//全局变量，用来记录ScrollView的滚动状态，1表示开始滚动，2表示正在滚动，0表示停止滚动
private int scrollState;
//可加载记录的条数
private int count = 100;
private int lastItem;
//当前可见页面中的Item总数
private int visibleItemCount;

private Button footerButton;
private LinearLayout footerProgressBarLayout;
private View view;
private ListAdapter mAdapter = new ListAdapter();

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//加载主页面布局
setContentView(R.layout.main);

LayoutInflater inflater = LayoutInflater.from(this);
//加载底部布局
view = inflater.inflate(R.layout.main_more, null);
footerButton = (Button) view.findViewById(R.id.button);
footerProgressBarLayout = (LinearLayout) view.findViewById(R.id.linearlayout);
footerProgressBarLayout.setVisibility(View.GONE);
//更多按钮点击事件
footerButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {
if(lastItem == mAdapter.count && scrollState == OnScrollListener.SCROLL_STATE_IDLE){
//设置页面底部布局控件可见性
footerButton.setVisibility(View.GONE);
footerProgressBarLayout.setVisibility(View.VISIBLE);
if(mAdapter.count <= count){
//使用Handler动态加载数据
new Handler().postDelayed(new Runnable() {

public void run() {
mAdapter.count += 10;
mAdapter.notifyDataSetChanged();
listView.setSelection(lastItem - visibleItemCount + 1);
//获取数据成功设置Layout不可见,Button设为可见
footerButton.setVisibility(View.VISIBLE);
footerProgressBarLayout.setVisibility(View.GONE);
}
} , 2000);
}
}
}
});

listView = getListView();
//将布局添加到ListView的Footer中
listView.addFooterView(view);
listView.setAdapter(mAdapter);

//设置滑动监听
listView.setOnScrollListener(this);
}

public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
this.visibleItemCount = visibleItemCount;
lastItem = firstVisibleItem + visibleItemCount - 1;
if(mAdapter.count >= count){
listView.removeFooterView(view);
}

//        boolean loadMore = firstVisibleItem + visibleItemCount >= totalItemCount;
//        if(loadMore){
//          mAdapter.count += visibleItemCount;
//          mAdapter.notifyDataSetChanged();
//        }
}

public void onScrollStateChanged(AbsListView view, int scrollState) {
this.scrollState = scrollState;
}

/**
* 数据匹配器
* @author qin_lei
*
*/
public class ListAdapter extends BaseAdapter{

int count = 10;

public int getCount() {
return count;
}

public Object getItem(int position) {
return position;
}

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

public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(MainActivity.this);
View view = inflater.inflate(R.layout.main_item, null);
TextView tv = (TextView) view.findViewById(R.id.tv);
tv.setText("Hello " + position);
return view;
}
}
}

主要布局文件代码如下：

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>

main_more.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button
android:id="@+id/button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="更多"/>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="@+id/linearlayout">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="正在获取..."/>
</LinearLayout>
</LinearLayout>

ListView单个显示item布局main_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/icon_head"/>
<TextView
android:id="@+id/tv"
android:layout_width="fill_parent"
android:layout_height="20dp"
android:text="@string/hello"/>
</LinearLayout>

项目运行结果如下图：



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