EditText在数字类型下hint的问题

<EditText
android:id="@+id/edittext_1"
android:gravity="center"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="number"
android:hint="Hint #1"
/>

设置的时候竟然不能显示hint内容，android:numeric="integer"却是可以的

final int oldgrav = _points.getGravity();
_points.setOnKeyListener(new OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent
event) {
if (_points.getText().toString().equals(""))
_points.setGravity(oldgrav);
else
_points.setGravity(Gravity.CENTER);
return false;
}
});