<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=""

    />

public class MainActivity extends Activity {

    String[] str = new String[] { "java入门到精通", "javascript浅析", "javaemail技术大全",

            "javaweb开发指南" };

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.auto);

        AutoCompleteTextView ac = (AutoCompleteTextView) findViewById(R.id.auto);

        ac.setAdapter(new ArrayAdapter<String>(this,

                android.R.layout.simple_dropdown_item_1line, str));

    }

}