自定义View之PopupWindow的使用

PopupWindow是Android上自定义弹出窗口，使用起来很方便。

PopupWindow的构造函数为

public PopupWindow(View contentView, int width, int height, boolean focusable)

contentView为要显示的view，width和height为宽和高，值为像素值，也可以是MATCHT_PARENT和WRAP_CONTENT。

focusable为是否可以获得焦点，这是一个很重要的参数，也可以通过

public void setFocusable(boolean focusable)

来设置，如果focusable为false，在一个Activity弹出一个PopupWindow，按返回键，由于PopupWindow没有焦点，会直接退出Activity。如果focusable为true，PopupWindow弹出后，所有的触屏和物理按键都有PopupWindows处理。

如果PopupWindow中有Editor的话，focusable要为true。

我们在popupwindow中包含一个listView作为他的子View

首先上mainactivity

package com.example.pullup;

import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.PopupWindow;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private ImageView upimage;
    private EditText et_1;
    private ListView listView;
    private ArrayList<String> arr;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        upimage= (ImageView) findViewById(R.id.upimage);
        et_1= (EditText) findViewById(R.id.et_1);
        upimage.setOnClickListener(this);
        initdata();
        listView=new ListView(this);
        listView.setAdapter(new Myadpter(this,arr,et_1));

    }

    private void initdata() {
        arr=new ArrayList<>();
        for (int i=0;i<10;i++){
           arr.add("aaaa"+i);
        }
        

    }
    private PopupWindow popupWindow;
    @Override
    public void onClick(View v) {
	//点击后构造popupwindow
        if (popupWindow==null) {
            popupWindow = new PopupWindow();
            popupWindow.setWidth(et_1.getWidth());
            popupWindow.setHeight(200);
            popupWindow.setContentView(listView);
        /*
        * 这三行是作用是点击别的地方隐藏popupwindows
        * */
           popupWindow.setTouchable(true);
            popupWindow.setOutsideTouchable(true);
            popupWindow.setBackgroundDrawable(new BitmapDrawable(getResources(),(Bitmap) null));

        }

	//在et_1的下方显示
        popupWindow.showAsDropDown(et_1,0,0);

/*

还有其他显示方式：

*/
    }
}

再上我们Listview的Adapter

package com.example.pullup;

import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * Created by yang on 2017/7/3.
 */
public class Myadpter extends BaseAdapter{

    private ArrayList<String> arr;
    private Context Mycontext;
    private TextView textView;

    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            Bundle bundle= msg.getData();
            String text=bundle.getString("data");
            textView.setText(text);
        }
    };

    public Myadpter(Context contexts,ArrayList<String> arr,TextView textView){
        this.arr=arr;
        this.Mycontext=contexts;
        this.textView=textView;
    }
    @Override
    public int getCount() {
        return arr.size();
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        View view;
        final ViewHoder viewHoder;
        if (convertView==null){
            view= View.inflate(Mycontext,R.layout.listview_items,null);
            viewHoder=new ViewHoder();
            viewHoder.imageView1= (ImageView) view.findViewById(R.id.iv_1);
            viewHoder.textView= (TextView) view.findViewById(R.id.tv_1);
            viewHoder.imageView2= (ImageView) view.findViewById(R.id.iv_2);
            view.setTag(viewHoder);
        }else {
            view= convertView;
            viewHoder= (ViewHoder) view.getTag();
        }
        viewHoder.textView.setText(arr.get(position));

        viewHoder.imageView2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                arr.remove(position);
                notifyDataSetChanged();
            }
        });
        viewHoder.textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Message msg=new Message();
                Bundle bundle=new Bundle();
                bundle.putString("data",viewHoder.textView.getText().toString().trim());
                msg.setData(bundle);
                handler.sendMessage(msg);
            }
        });
        return view;

    }
    class ViewHoder{
        private ImageView imageView1;
        private TextView textView;
        private ImageView imageView2;
    }
}

最后上XML文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.pullup.MainActivity">

    <EditText
        android:id="@+id/et_1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:paddingRight="20dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_name"
        android:maxLines="1" />
    <ImageView
        android:id="@+id/upimage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@id/et_1"
        android:layout_alignTop="@id/et_1"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        android:background="@drawable/down_arrow"
        />
</RelativeLayout>

功能使用：

点击图片弹出popupwindow

点击listview的删除按钮删除条目：

arr.remove(position);
notifyDataSetChanged();

点击listview的内容显示在EditView中

这里用Handler实现

上效果图：