<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:app="http://schemas.android.com/apk/res-auto" 
 xmlns:tools="http://schemas.android.com/tools" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 tools:context="com.amy.searchtest.MainActivity"> 
<LinearLayout 
 android:orientation="horizontal" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent"> 
 
 <AutoCompleteTextView 
 android:id="@+id/autoCompleteTextView1" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:text="" 
 android:completionThreshold="2" 
 android:completionHint="请输入搜索内容..." 
 android:layout_weight="7"/> 
 
 <Button 
 android:id="@+id/button1" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:text="搜索" 
 android:layout_weight="1" 
 android:layout_marginLeft="10px"/> 
 
 
</LinearLayout> 
 
</android.support.constraint.ConstraintLayout> 

package com.amy.searchtest; 
 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.ArrayAdapter; 
import android.widget.AutoCompleteTextView; 
import android.widget.Button; 
import android.widget.Toast; 
 
public class MainActivity extends AppCompatActivity { 
 
 public static final String[] CONTENTS = new String[]{"zg陕西","zg海南","zg新疆","zg西藏"}; 
 AutoCompleteTextView textView; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 textView = (AutoCompleteTextView)findViewById(R.id.autoCompleteTextView1); 
 //创建一个ArrayAdapter适配器 
 ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line,CONTENTS); 
 textView.setAdapter(adapter); 
 
 Button button = (Button) findViewById(R.id.button1); 
 button.setOnClickListener(new View.OnClickListener() { 
  @Override 
  public void onClick(View v) { 
  Toast.makeText(MainActivity.this, textView.getText().toString(),Toast.LENGTH_SHORT).show(); 
  } 
 }); 
 } 
 
}