Android自定义spinner下拉框实现的实现

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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