public class MainActivity extends AppCompatActivity {
    private AutoCompleteTextView atTextView;
    private String[] res = {"qingyehaoshuai","qingyeshangtoutiao","qingyeshangremn","mayouyouyoudianmeng"};
    //第一步：初始化控件
    //第二部：创建一个适配器
    //第三步：初始化数据源--这数据源去匹配文本框输入的内容
    //第四步：将adapter与当前的AutocomleteTextView绑定
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        atTextView = (AutoCompleteTextView)findViewById(R.id.autoCompleteTextView);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_expandable_list_item_1,res);
        atTextView.setAdapter(adapter);
        //android.R.layout.simple_expandable_list_item_1是布置格局
        macTextView = (MultiAutoCompleteTextView)findViewById(R.id.multiAutoCompleteTextView);
        macTextView.setAdapter(adapter);
        //设置以逗号为分隔符为结束的符号
        macTextView.setTokenizer(new
MultiAutoCompleteTextView.CommaTokenizer());

    }
}

android:completionThreshold="3" //匹配字符数
layout_marginTop //组件距离
MultiAutoCompleteTextView：可以多次匹配
AutoCompleteTextView：只能匹配一次