<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical"

    >

    <AutoCompleteTextView

        android:id="@+id/auto"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:completionHint="请选择您喜欢的图书"

        android:dropDownHorizontalOffset="20dp"

        android:completionThreshold="1"

        />

</LinearLayout>

package com.example.autocompletetextview;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

import android.widget.ArrayAdapter;

import android.widget.AutoCompleteTextView;

public class MainActivity extends Activity {

	//定义字符串数组，作为提示文本

	String[]  books = new String[]{

			"aaa",

			"abbb",

			"accc",

			"addd",

	};

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		//创建一个ArrayAdapter,封装数组

		ArrayAdapter<String> aa = new ArrayAdapter<String>(

				this,

				android.R.layout.simple_dropdown_item_1line,

				books);

		AutoCompleteTextView actv = (AutoCompleteTextView)

				findViewById(R.id.auto);

		//设置adapter

		actv.setAdapter(aa);

	}

}