android的ListView点击item使item展开的做法

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

private ArrayList<MyData> myList = new ArrayList<MyData>();
private myAdapter myAdapter;
private LayoutInflater inflater = null;
private int oldPostion = -1;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ListView list = (ListView) findViewById(R.id.draggable_list);
MyData data = new MyData();
data.name = "11";
myList.add(data);

data = new MyData();
data.name = "22";
myList.add(data);

data = new MyData();
data.name = "33";
myList.add(data);

data = new MyData();
data.name = "44";
myList.add(data);

data = new MyData();
data.name = "55";
myList.add(data);

data = new MyData();
data.name = "66";
myList.add(data);

data = new MyData();
data.name = "77";
myList.add(data);

inflater = LayoutInflater.from(this);
TextView header = (TextView)inflater.inflate(R.layout.header, null);
TextView footer = (TextView)inflater.inflate(R.layout.footer, null);

//list.addFooterView(footer);
//list.addHeaderView(header);
myAdapter = new myAdapter();
list.setAdapter(myAdapter);

list.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
MyData data = myList.get(position);
if (oldPostion == position) {
if (data.expand)  {
oldPostion = -1;
}
data.expand = !data.expand;
}else{
oldPostion = position;
data.expand = true;
}

int totalHeight = 0;
for(int i=0;i<myAdapter.getCount();i++) {
View viewItem = myAdapter.getView(i, null, list);//这个非常重要。那个展开的item的measureHeight比其它的大
viewItem.measure(0, 0);
totalHeight += viewItem.getMeasuredHeight();
}

ViewGroup.LayoutParams params = list.getLayoutParams();
params.height = totalHeight
+ (list.getDividerHeight() * (list.getCount() - 1));
list.setLayoutParams(params);
myAdapter.notifyDataSetChanged();
}
});
Button btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {

}
});

}

private class myAdapter extends BaseAdapter{

@Override
public int getCount() {
return myList.size();
}

@Override
public Object getItem(int position) {
return myList.get(position);
}

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

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

MyTag tag = new MyTag();
MyData data = myList.get(position);
if(convertView == null) {
convertView = inflater.inflate(R.layout.item_layout, null);
tag.item1 = (TextView)convertView.findViewById(R.id.item1);
tag.item2 = (RelativeLayout)convertView.findViewById(R.id.item2);
convertView.setTag(tag);
}else{
tag = (MyTag)convertView.getTag();
}
if(data.expand) {
tag.item2.setVisibility(View.VISIBLE);
}else{
tag.item2.setVisibility(View.GONE);
}

tag.item1.setText(data.name);
return convertView;
}

}

private class MyTag{
private TextView item1;
private RelativeLayout item2;
}

private class MyData{
boolean expand;
String name;
}

}

<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="wrap_content"
android:minHeight="50dp" >

<TextView
android:id="@+id/item1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:layout_centerHorizontal="true"
android:gravity="center"
android:text="Header"
android:textColor="#000000"
android:textSize="20sp" >
</TextView>

<RelativeLayout
android:id="@+id/item2"
android:layout_below="@id/item1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="35dp"
android:background="#fffeee"
android:visibility="gone" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:gravity="center"
android:text="Expand"
android:textColor="#000000"
android:textSize="16sp" >
</TextView>
</RelativeLayout>

</RelativeLayout>