Android 简单封装一个精美、好用的菜单型PopupWindow

先上效果图：

就是这样一个菜单型的PopupWindow，现在说下是怎么弄的，
先看一个布局文件，这个布局文件

package cn.edu.jxufe.popupwindowdemo;

import android.content.Context;
import android.graphics.drawable.BitmapDrawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.PopupWindow;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class PopupWindowUtil {

    private ListView listView;
    private PopupWindow window;
    //窗口在x轴偏移量
    private int xOff = 0;
    //窗口在y轴的偏移量
    private int yOff = 0;

    public PopupWindowUtil(Context context, List<String> datas) {

        window = new PopupWindow(context);
        //ViewGroup.LayoutParams.WRAP_CONTENT，自动包裹所有的内容
        window.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
        window.setFocusable(true);
        //点击 back 键的时候，窗口会自动消失
        window.setBackgroundDrawable(new BitmapDrawable());

        View localView = LayoutInflater.from(context).inflate(R.layout.lv_pw_menu, null);
        listView = (ListView) localView.findViewById(R.id.lv_pop_list);

        listView.setAdapter(new MyAdapter(context, datas));
        listView.setTag(window);
        //设置显示的视图
        window.setContentView(localView);
    }

    public void setItemClickListener(AdapterView.OnItemClickListener listener) {
        listView.setOnItemClickListener(listener);
    }

    public void dismiss() {
        window.dismiss();
    }

    /**
     * @param xOff x轴（左右）偏移
     * @param yOff y轴（上下）偏移
     */
    public void setOff(int xOff, int yOff) {
        this.xOff = xOff;
        this.yOff = yOff;
    }

    /**
     * @param paramView 点击的按钮
     */
    public void show(View paramView, int count) {
        //该count 是手动调整窗口的宽度
        window.setWidth(paramView.getWidth() * count);
        //设置窗口显示位置, 后面两个0 是表示偏移量，可以自由设置
        window.showAsDropDown(paramView, xOff, yOff);
        //更新窗口状态
        window.update();
    }

    class MyAdapter extends BaseAdapter {

        private Context context;
        private List<String> mDatas;

        public MyAdapter(Context context, List<String> datas) {
            this.context = context;
            if (datas == null) {
                datas = new ArrayList<>();
            }
            mDatas = datas;
        }

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

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

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            TextView tvItem;
            if (convertView == null) {
                convertView = LayoutInflater.from(context).inflate(R.layout.lv_item_pw_menu, null);
                tvItem = (TextView) convertView.findViewById(R.id.tv_item_pw_menu);
                convertView.setTag(tvItem);
            } else {
                tvItem = (TextView) convertView.getTag();
            }
            tvItem.setText(getItem(position) + "");
            return convertView;
        }
    }
}

再看看Activity中是怎么调用的

public class MenuActivity extends Activity {

    private Context context = this;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);
    }
    //菜单按钮onClick事件
    public void menuClick(View view) {
        final List<String> items = new ArrayList<>();
        items.add("第一项");
        items.add("第二项");
        items.add("第三项");
        items.add("第四项");

        final PopupWindowUtil popupWindow = new PopupWindowUtil(context, items);
        popupWindow.setItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                popupWindow.dismiss();
                Toast.makeText(context, "你点击了" + items.get(position), Toast.LENGTH_SHORT).show();
            }
        });
        //根据后面的数字 手动调节窗口的宽度
        popupWindow.show(view, 4);
    }
}

接下来是布局文件 lv_item_pw_menu
ListView的item布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:gravity="center_vertical"
    android:layout_width="match_parent"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:background="@android:color/transparent"
    android:layout_marginBottom="8dp"
    android:layout_height="wrap_content">

    <TextView
        android:layout_width="match_parent"
        android:gravity="center"
        android:drawablePadding="3dp"
        android:padding="7dp"
        android:text="测试数据"
        android:id="@+id/tv_item_pw_menu"
        android:textSize="18sp"
        android:layout_height="wrap_content" />

</RelativeLayout>

窗口的布局 lv_pw_menu.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:background="@drawable/menu"
    android:layout_height="match_parent"
    android:paddingBottom="15.0dip"
    android:paddingLeft="6.0dip"
    android:paddingRight="6.0dip"
    android:paddingTop="20.0dip">

    <ListView
        android:id="@+id/lv_pop_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:cacheColorHint="@null"
        android:scrollbars="none" />
</LinearLayout>

就这样，以后就可以直接在activity中调用，且无需在工具类中修改

附上链接，只有代码和图片：
http://download.csdn.net/detail/chang_1134/9516120