Popupwindow实现自定义的下拉菜单

<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=".MainActivity" >

<EditText
android:id="@+id/input"
android:layout_width="200dip"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="110dip"
android:text="@string/hello_world" />

<ImageView
android:id="@+id/down_arrow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/down_arrow"
android:layout_alignRight="@id/input"
android:clickable="true"
android:layout_marginTop="120dip"
/>
</RelativeLayout>

<LinearLayout 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:gravity="center_vertical"
android:orientation="horizontal"
tools:context=".MainActivity" >

<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/user" />

<TextView
android:id="@+id/tv_list_item"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center_horizontal"
android:text="@string/hello_world" />

<ImageView
android:id="@+id/delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/delete" />

</LinearLayout>

public class MainActivity extends Activity {

protected static final String TAG = "MainActivity";
private EditText et_input;
private ImageView iv_downarrow;
private ListView listview;
private PopupWindow popwin;
private List<String> msgList;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

et_input = (EditText) findViewById(R.id.input);
iv_downarrow = (ImageView) findViewById(R.id.down_arrow);
msgList = new ArrayList<String>();
//初始化菜单信息
for(int i=0;i<20;i++){
msgList.add("1818899000"+i);
}

initView();

iv_downarrow.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//定义 popupWindow
popwin = new PopupWindow(MainActivity.this);
popwin.setWidth(et_input.getWidth());//设置宽度
popwin.setHeight(200);//设置宽度
popwin.setContentView(listview);//为popwin填充内容
popwin.setOutsideTouchable(true);//设置点击popwin以外的区域，总的关闭popwin
popwin.showAsDropDown(et_input, 0, 0);//设置popwin的位置，在et_input下xy偏移量为0
}
});

}

private void initView() {
// TODO Auto-generated method stub
listview = new ListView(this);
listview.setBackgroundResource(R.drawable.listview_background);//设置listView 背景
listview.setDivider(null);//设置条目之间的分隔线为null
listview.setVerticalScrollBarEnabled(false);//设置listview垂直方向滚动条隐藏
listview.setAdapter(new MyAdapter());
}

private class MyAdapter extends BaseAdapter{

@Override
public int getCount() {
// TODO Auto-generated method stub
return msgList.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder;
if(convertView == null){
convertView = View.inflate(MainActivity.this, R.layout.list_item, null);
holder = new ViewHolder();

holder.tv_msg = (TextView) convertView.findViewById(R.id.tv_list_item);
holder.iv_del = (ImageView) convertView.findViewById(R.id.delete);
convertView.setTag(holder);
}else{
holder = (ViewHolder) convertView.getTag();
}

holder.tv_msg.setText(msgList.get(position));
holder.iv_del.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//删除对应条目
msgList.remove(position);
//更新adapter数据
MyAdapter.this.notifyDataSetChanged();
}
});
convertView.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//设置输入框
et_input.setText(msgList.get(position));
popwin.dismiss();
}
});

return convertView;
}

private class ViewHolder{
private TextView tv_msg;
private ImageView iv_del;
}

}

}