the keyboard is covered by the systme toolbar in the landscape mode

I create a Activity, it just have a button, click the button to show a PopupWindow, the PopupWindow has a Edittext, when i click it to input something, the keyboard display incorrectly, the character "p" is covered by the system toolbar, but it work good in the portrait mode. When i replace the PopupWindow to Dailog, thera's not this question.