首先是布局文件activity_auto_complete.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".AutoCompleteActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="爱好："
            android:textSize="25sp" />

        <AutoCompleteTextView
            android:id="@+id/auto_tv1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:completionThreshold="1"
            android:hint="请输入您的爱好" />
    </LinearLayout>

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="获取文本框中的值"
        android:textSize="20sp" />

</LinearLayout>

之后在res/values目录下创建array.xml资源文件

<resources>
    <string-array name="hobby">
        <item>读书</item>
        <item>跑步</item>
        <item>唱歌</item>
        <item>旅游</item>
        <item>写代码</item>
        <item>写字</item>
        <item>篮球</item>
        <item>乒乓球</item>
    </string-array>
</resources>

之后在AutoCompleteActivity文件中通过系统提供的数组适配器ArrayAdapter，显示数据。

public class AutoCompleteActivity extends AppCompatActivity {
    private AutoCompleteTextView auto_tv1;
    private ArrayAdapter arrayAdapter;
    private String[] data = new String[]{"读书", "跑步", "唱歌", "旅游", "写代码", "篮球", "乒乓球"};
    private Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_auto_complete);
        auto_tv1 = findViewById(R.id.auto_tv1);
        btn = findViewById(R.id.btn);


//        arrayAdapter = new ArrayAdapter(this, R.layout.support_simple_spinner_dropdown_item,data );
        arrayAdapter = ArrayAdapter.createFromResource(this,R.array.hobby,R.layout.support_simple_spinner_dropdown_item);
        auto_tv1.setAdapter(arrayAdapter);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(AutoCompleteActivity.this, auto_tv1.getText().toString(), Toast.LENGTH_SHORT).show();
            }
        });
    }
}

效果图显示：

Android 自动补齐文本框AutoCompleteTextView的使用_android