一:前言
本人参考博客:http://blog.csdn.net/jdsjlzx/article/details/41316417 最近在弄一个下拉框,发现Android自带的很难实现我的功能,于是去网上找到一份Demo,但是发现没有封装的好,并且还有很多重复的代码,于是我在这位前辈的基础上进行了修改.并且重新进行了封装,代码变得简单,并且具有可读性.
二:实现原理
1.就是一个TextView 弄一个弧形的背景图片,然后设置一个点击事件.
2.点击TextView之后显示一个PopupWindow,Popupwindow是自定义的,里面显示一个ListView.ListView也设置了左边.右边.底部的边框.
三:效果图如下
四:代码实现:
1).MainActivity.java 程序入口,初始化数据,初始化自定义PopupWIndow,TextView点击之后显示PopupWIndow,处理ListView的点击事件.
/**
* 主Activity 用来实现popupwindow
* @author ansen
*/
public class MainActivity extends Activity {
private SpinerPopWindow<String> mSpinerPopWindow;
private List<String> list;
private TextView tvValue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
tvValue = (TextView) findViewById(R.id.tv_value);
tvValue.setOnClickListener(clickListener);
mSpinerPopWindow = new SpinerPopWindow<String>(this, list,itemClickListener);
mSpinerPopWindow.setOnDismissListener(dismissListener);
}
/**
* 监听popupwindow取消
*/
private OnDismissListener dismissListener=new OnDismissListener() {
@Override
public void onDismiss() {
setTextImage(R.drawable.icon_down);
}
};
/**
* popupwindow显示的ListView的item点击事件
*/
private OnItemClickListener itemClickListener = new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
mSpinerPopWindow.dismiss();
tvValue.setText(list.get(position));
Toast.makeText(MainActivity.this, "点击了:" + list.get(position),Toast.LENGTH_LONG).show();
}
};
/**
* 显示PopupWindow
*/
private OnClickListener clickListener = new OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.tv_value:
mSpinerPopWindow.setWidth(tvValue.getWidth());
mSpinerPopWindow.showAsDropDown(tvValue);
setTextImage(R.drawable.icon_up);
break;
}
}
};
/**
* 初始化数据
*/
private void initData() {
list = new ArrayList<String>();
for (int i = 0; i < 5; i++) {
list.add("test:" + i);
}
}
/**
* 给TextView右边设置图片
* @param resId
*/
private void setTextImage(int resId) {
Drawable drawable = getResources().getDrawable(resId);
drawable.setBounds(0, 0, drawable.getMinimumWidth(),drawable.getMinimumHeight());// 必须设置图片大小，否则不显示
tvValue.setCompoundDrawables(null, null, drawable, null);
}
}2).activity_main.xml 这个文件也没啥好说的 就是两个TextView。
<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="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:orientation="horizontal">
<TextView
android:id="@+id/tv_value"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/shape_help_category_tv_bg"
android:drawableRight="@drawable/icon_down"
android:padding="10dp"
android:textColor="@color/content_color"
android:text="请选择父类别"
android:textSize="20sp"/>
<TextView
android:layout_marginLeft="5dp"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/shape_help_category_tv_bg"
android:drawableRight="@drawable/icon_down"
android:textColor="@color/content_color"
android:padding="10dp"
android:text="请选择子类别"
android:textSize="20sp" />
</LinearLayout>
</LinearLayout>
3).SpinerPopWindow.java 自定义Popupwindow类 初始化PopupWindow显示的布局,以及一些参数,并且给listView设置适配器
* 自定义PopupWindow 主要用来显示ListView
* @author Ansen
* @param <T>
* @param <T>
* @create time 2015-11-3
*/
public class SpinerPopWindow<T> extends PopupWindow {
private LayoutInflater inflater;
private ListView mListView;
private List<T> list;
private MyAdapter mAdapter;
public SpinerPopWindow(Context context,List<T> list,OnItemClickListener clickListener) {
super(context);
inflater=LayoutInflater.from(context);
this.list=list;
init(clickListener);
}
private void init(OnItemClickListener clickListener){
View view = inflater.inflate(R.layout.spiner_window_layout, null);
setContentView(view);
setWidth(LayoutParams.WRAP_CONTENT);
setHeight(LayoutParams.WRAP_CONTENT);
setFocusable(true);
ColorDrawable dw = new ColorDrawable(0x00);
setBackgroundDrawable(dw);
mListView = (ListView) view.findViewById(R.id.listview);
mListView.setAdapter(mAdapter=new MyAdapter());
mListView.setOnItemClickListener(clickListener);
}
private class MyAdapter extends BaseAdapter{
@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){
holder=new ViewHolder();
convertView=inflater.inflate(R.layout.spiner_item_layout, null);
holder.tvName=(TextView) convertView.findViewById(R.id.tv_name);
convertView.setTag(holder);
}else{
holder=(ViewHolder) convertView.getTag();
}
holder.tvName.setText(getItem(position).toString());
return convertView;
}
}
private class ViewHolder{
private TextView tvName;
}
}4).spiner_window_layout.xml PopupWindow显示的布局文件 里面就一个ListView控件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:orientation="vertical">
<ListView
android:id="@+id/listview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:cacheColorHint="#00000000"
android:background="@drawable/shape_popupwindow_list_bg"
android:scrollbars="none" >
</ListView>
</LinearLayout>
还有一些其他布局,我就不一一贴出来了,有兴趣的可以去看看源码.这个Demo还是比较简单的,相信大家都能看懂.
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