定义LIstView下拉加载数据

妙语皆随晨曦出 2016-12-11 22:57

ListView下拉加载更多数据

1.创建footerView布局footer.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/footerLLayout"

android:layout_width="match_parent"

android:layout_height="60dp"

android:orientation="horizontal">

<ProgressBar

android:layout_width="0dp"

android:layout_height="match_parent"

android:layout_weight="2"/>

<TextView

android:layout_width="0dp"

android:layout_height="match_parent"

android:text="加载更多"

android:gravity="center|left"

android:layout_weight="3"/>

</LinearLayout>

2.重写ListView，监听滚动状态，定义加载数据接口

public class FooterListView extends ListView implements AbsListView.OnScrollListener{

public FooterListView(Context context, AttributeSet attrs) {

super(context, attrs);

addFooterView();

}

public FooterListView(Context context) {

super(context);

addFooterView();

}

/**

* 重写ListView 添加FooterView

*/

private View footerView;

private void addFooterView(){

footerView=LayoutInflater.from(getContext()).inflate(R.layout.footer,null);

addFooterView(footerView);

footerView.setVisibility(View.GONE);//初始状态 footerView不显示

setOnScrollListener(this);

}

@Override

public void onScrollStateChanged(AbsListView view, int scrollState) {

//最后一个可见的Item id==item总数，已经滑动到底部了，并且停止滚动了，那么就加载数据

if(totalItemCount==firstVisibleItem+visibleItemCount && scrollState==SCROLL_STATE_IDLE){

if (iLoadListener!=null) {

footerView.setVisibility(View.VISIBLE);//加载数据 footerView显示

iLoadListener.loadData();//调用接口加载数据

}

}

Log.d(TAG,"onScrollStateChanged");

}

@Override

public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

this.firstVisibleItem=firstVisibleItem;

this.visibleItemCount=visibleItemCount;

this.totalItemCount=totalItemCount;

Log.d(TAG,"onScroll");

}

//ListView的第一个Item，可见Item的总数，ListViewItem的总数

private int firstVisibleItem,visibleItemCount,totalItemCount;

private String TAG=FooterListView.class.getSimpleName();

//数据加载完成隐藏footerView

public void loadComplete(){

footerView.setVisibility(View.GONE);

}

//定义加载数据的接口

public interface ILoadListener{

void loadData();

}

private ILoadListener iLoadListener;

public void setiLoadListener(ILoadListener iLoadListener){

this.iLoadListener=iLoadListener;

}

}

3.创建ListAdapter布局item.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="50dp">

<TextView

android:id="@+id/tv"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:gravity="center"

android:textSize="16sp"/>

</LinearLayout>

4.定义ListAdapter

public class ListAdapter extends BaseAdapter {

private Context context;

private List<String> list;

public ListAdapter(Context context, List<String> list) {

this.context = context;

this.list = list;

}

@Override

public int getCount() {

return list.size();

}

@Override

public Object getItem(int position) {

return list.get(position);

}

@Override

public long getItemId(int position) {

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

ViewHolder holder=null;

if(convertView==null){

convertView= LayoutInflater.from(context).inflate(R.layout.item,parent,false);

holder=new ViewHolder();

holder.tv=(TextView) convertView.findViewById(R.id.tv);

convertView.setTag(holder);

}else{

holder=(ViewHolder) convertView.getTag();

}

holder.tv.setText(list.get(position));

return convertView;

}

static class ViewHolder{

TextView tv;

}

}

5.在MainActivity中实现加载数据接口

public class MainActivity extends Activity implements FooterListView.ILoadListener {

private FooterListView listView;

private ListAdapter adapter;

private List<String> data=new ArrayList<String>();

{

data.add("第1条数据");

data.add("第2条数据");

data.add("第3条数据");

data.add("第4条数据");

data.add("第5条数据");

data.add("第6条数据");

data.add("第7条数据");

data.add("第11条数据");

data.add("第21条数据");

data.add("第31条数据");

data.add("第41条数据");

data.add("第51条数据");

data.add("第61条数据");

data.add("第71条数据");

}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

listView=(FooterListView) findViewById(R.id.listView);

listView.setiLoadListener(this);

adapter=new ListAdapter(this,data);

listView.setAdapter(adapter);

}

@Override

public void loadData() {

new Handler().postDelayed(new Runnable() {

@Override

public void run() {

data.add("新添加的数据1");

data.add("新添加的数据2");

adapter.notifyDataSetChanged();

listView.loadComplete();//加载完成

}

},10000);

}

}

6.MainActivity布局activity_main.xml

<?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.ruhu.listviewfooterloadmore.MainActivity">

<com.example.ruhu.listviewfooterloadmore.FooterListView

android:id="@+id/listView"

android:layout_width="match_parent"

android:layout_height="wrap_content"/>

</RelativeLayout>

7.运行结果

7.1初始状态



7.2正在加载



7.3加载完成