Android :datepicker's spinner doesn't show

 <DatePicker
    android:id="@+id/datePicker1"
    style="@style/AppTheme"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"

    />

The spinner show month,day and year,but the calendar covers the year.The year doesn't show on this layout.How to solve this question?