1、如何實現：將一個EditText和ListView+PopupWindow 結合起來。自定義一個EditText，在自定義控制元件中用PopupWindow實現彈出ListView，已達到想要的效果。

2、需要的佈局： 1、EditText+ImageButton 的佈局  

     2、ListView的佈局  

3、程式碼

EditText+ImageButton 的佈局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="40dp">
    <EditText
        android:id="@+id/CD_Et_account"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginLeft="30dp"
        android:layout_weight="1"
        android:background="@null"
        android:hint="賬號" />

    <ImageButton
        android:id="@+id/CD_Iv_drop_image"
        android:layout_width="40dp"
        android:layout_height="match_parent"
        android:layout_gravity="center_vertical"
        android:layout_marginBottom="2dip"
        android:layout_marginRight="5dp"
        android:layout_marginTop="2dip"
        android:background="@drawable/drop"
        android:paddingRight="2dip"
        android:scaleType="fitXY" />
</LinearLayout>
 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:background="#ffffFF"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ListView
        android:layout_marginLeft="20dp"
        android:id="@+id/CD_pop"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></ListView>
</LinearLayout>
 

自定義控制元件java程式碼：

package com.wxcoming.wxcomingerp.custom.sptoedit;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.ColorDrawable;
import android.support.annotation.AttrRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.TextUtils;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.PopupWindow;

import com.wxcoming.wxcomingerp.R;

/**
 * Created by adolph_jun on 2017/10/13.
 */

public class CDropEditText extends FrameLayout implements View.OnClickListener, AdapterView.OnItemClickListener {
    private EditText mEt;
    private ImageButton mIb;
    private ListView mLv;
    private Context context;
    private PopupWindow popWindow;
    public CDropEditText(Context context) {
        super(context);
        this.context = context;
    }
    public CDropEditText(Context context,AttributeSet attrs) {
        super(context, attrs);
        //放在三個屬性的構造方法處會報錯
        LayoutInflater.from(context).inflate(R.layout.custome_dropedittext, this);
        mEt = (EditText) findViewById(R.id.CD_Et_account);
        mIb = (ImageButton) findViewById(R.id.CD_Iv_drop_image);
        initPopWindow(mIb);
    }
    public CDropEditText( Context context, AttributeSet attrs,int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
    }
    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        mIb.setOnClickListener(this);
        mLv.setOnItemClickListener(this);
    }
    /**
     * 編輯內容改變監聽
     * @param textWatcher
     */
    public void setEditChange(TextWatcher textWatcher){
        if(textWatcher!=null){
            mEt.addTextChangedListener(textWatcher);
        }
    }
    /**
     * 給list新增資料
     * @param adapter
     */
    public void setAdapter(BaseAdapter adapter){
        //popWindow.showAsDropDown(this, 0, 5);
        mLv.setAdapter(adapter);
    }
    private void initPopWindow(View v) {
        View view = LayoutInflater.from(getContext()).inflate(R.layout.pop_view, null, false);
        mLv = (ListView) view.findViewById(R.id.CD_pop);
        popWindow= new PopupWindow(view, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, true);
        popWindow.setTouchable(true);
        popWindow.setTouchInterceptor(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return false;
            }
        });
        popWindow.setBackgroundDrawable(new ColorDrawable(0x00000000));    //要為popWindow設定一個背景才有效
    }
    public void showPop(){//彈出listview
        popWindow.showAsDropDown(this, 0, 5);
    }


    @Override//下拉圖示按鈕監聽
    public void onClick(View v) {
        if(v.getId() == R.id.CD_Iv_drop_image) {
            if(popWindow.isShowing()) {
                popWindow.dismiss();
                return;
            }
            popWindow.showAsDropDown(this, 0, 5);
        }
    }
    @Override//listview中item的點選事件監聽
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        mEt.setText(mLv.getAdapter().getItem(position).toString());
        popWindow.dismiss();
    }
}