Activity activity = getActivity();
InputMethodManager inputMethodManager = (InputMethodManager)  activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
try
{
    inputMethodManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0);
}
catch (Exception e)
{

}

InputMethodManager imm = (InputMethodManager)this.getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(getWindow().getDecorView().getWindowToken(), 0);

class MyFrag extends Fragment{

  @Override
  public void onConfigurationChanged(Configuration config){
    //Check flags
    switch(config.keyboardHidden){
      case KEYBOARDHIDDEN_NO:
        // do something
        break;
      case KEYBOARDHIDDEN_YES:
        break;
    }
  }

}

<activity ...
  android:configChanges="keyboardHidden|orientation|screenSize|screenLayout"/>

Configuration config = getResources().getConfiguration();

@Override
protected void onPause() {
    super.onPause();

    final InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Activity.INPUT_METHOD_SERVICE);
    if (inputMethodManager != null && inputMethodManager.isActive()) {
        if (getCurrentFocus() != null) {
            inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
        }
    }
}