Android AutoCompleteTextView

public class MainActivity extends AppCompatActivity {    // 模拟actv这个控件要显示的数据    private String[] COUNTRIES = new String[] { "laofang", "laoli", "laozhang", "laobi", "laowang","aa","abb","ccc"};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //1 找到控件        AutoCompleteTextView actv = (AutoCompleteTextView) findViewById(R.id.actv);        //2 actv这个控件显示数据的原理和listview一样，需要一个数据适配器        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, COUNTRIES);        //3 显示数据        actv.setAdapter(adapter);    }}