FullScreen removed after soft keyboard use

Hello, my sketch runs in fullscreen (and orientation(landscape))and it's OK. But when I open a soft keyboard with:

void showSoftKeyboard() {
android.view.inputmethod.InputMethodManager imm = (android.view.inputmethod.InputMethodManager) getActivity().getSystemService(android.content.Context.INPUT_METHOD_SERVICE);
  imm.showSoftInput(getActivity().getCurrentFocus(), 0);
   }

void hideSoftKeyboard() {
android.view.inputmethod.InputMethodManager imm = (android.view.inputmethod.InputMethodManager) getActivity().getSystemService(android.content.Context.INPUT_METHOD_SERVICE);
  imm.hideSoftInputFromWindow(getActivity().getCurrentFocus().getWindowToken(), 0);
  deci=0;
   }

The fullscreen disappears and it's impossible to remove the task bar on the right of the screen.
Any idea?
Thanks in advance