【Android进阶学习】Popupwindow的应用

PopupWindow 是一种阻塞式的弹出窗口，这就意味着在我们退出这个弹出框之前，程序会一直等待。它可以浮动在当前Activity的任何的位置上。 需要注意的是，PopupWindow必须触发某个焦点或者某个事件才会显示出来，不然总会会出现错误。

下面是使用PopupWindow 弹出自定义菜单的例子

当我们点击Menu键的时候，会在当前的Activity最下方弹出一个菜单。

效果图如下：

 PopupMenuDemo.java

package com.lingdududu.popupWindow;

import android.app.Activity;
import android.content.Context;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.PopupWindow;
import android.widget.TextView;
import android.widget.LinearLayout.LayoutParams;

public class PopupMenuDemo extends Activity {

    private int[] resArray = new int[] {
            R.drawable.icon_menu_addto, R.drawable.icon_menu_audioinfo,
            R.drawable.icon_menu_findlrc, R.drawable.icon_menu_scan
    };

    private String[] title = new String[]{
            "添加", "信息", "搜索", "查看"
    };

    private PopupWindow pw = null;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add("");
        return super.onCreateOptionsMenu(menu);

    }

    /**
     * 在此方法中实现自定义菜单栏
     */
    public boolean onMenuOpened(int featureId, Menu menu) {
        if (pw != null) {
            if (pw.isShowing()) {
                // 就关闭弹出窗口
                pw.dismiss();
            }
            else {
                //在指定位置弹出窗口
                pw.showAtLocation(findViewById(R.id.tv), Gravity.CENTER, 0, 300);
            }
        }
        else {

            LayoutInflater inflater = (LayoutInflater)this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View view = inflater.inflate(R.layout.menu, null);
            GridView grid1 = (GridView)view.findViewById(R.id.menuGridChange);
            grid1.setAdapter(new ImageAdapter(this));


            //生成PopupWindow对象
            pw = new PopupWindow(view,LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);

            //在指定位置弹出窗口
            pw.showAtLocation(findViewById(R.id.tv), Gravity.CENTER, 0, 300);

        }
        // 此处返回false，系统不会执行onCreateOptionsMenu中添加的菜单
        return false;
    }


    public boolean onKeyDown(int keyCode, KeyEvent event) {

        if(keyCode==KeyEvent.KEYCODE_BACK){
            pw.dismiss();
            return false;
        }
        return super.onKeyDown(keyCode, event);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return super.onOptionsItemSelected(item);
    }


    public class ImageAdapter extends BaseAdapter {

        private Context context;

        public ImageAdapter(Context context) {
            this.context = context;
        }

        @Override
        public int getCount() {
            return resArray.length;
        }

        @Override
        public Object getItem(int arg0) {
            return resArray[arg0];
        }

        @Override
        public long getItemId(int arg0) {
            return arg0;
        }

        @Override
        public View getView(int arg0, View arg1, ViewGroup arg2) {
            LinearLayout linear = new LinearLayout(context);
            LinearLayout.LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            linear.setOrientation(LinearLayout.VERTICAL);

            ImageView iv = new ImageView(context);
            iv.setImageBitmap(((BitmapDrawable)context.getResources().getDrawable(resArray[arg0])).getBitmap());
            LinearLayout.LayoutParams params2 = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            params2.gravity=Gravity.CENTER;
            linear.addView(iv, params2);

            TextView tv = new TextView(context);
            tv.setText(title[arg0]);
            LinearLayout.LayoutParams params3 = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            params3.gravity=Gravity.CENTER;

            linear.addView(tv, params3);

            return linear;
        }
    }
}

main.xml

xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:id="@+id/tv"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
LinearLayout>

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="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:id="@+id/tv"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
LinearLayout>

 

menu_bg_frame.xml 这个文件是菜单背景的样式文件，在drawable-hdpi文件下面

xml version="1.0" encoding="UTF-8"?>
<shape android:shape="rectangle" xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#b4000000" />
    <stroke android:width="2.0dip" android:color="#b4ffffff" android:dashWidth="3.0dip" android:dashGap="0.0dip" />
    <padding android:left="7.0dip" android:top="7.0dip" android:right="7.0dip" android:bottom="7.0dip" />
    <corners android:radius="8.0dip" />
shape>