Android DialogFragment 遇到 java.lang.IllegalStateException: Fragment already added: 的解決方法

private CountryChooseDialog mCountryChooseDialog;
private void showCountryChooseDialog() {
    if (mCountryChooseDialog == null) {
      mCountryChooseDialog = CountryChooseDialog.newInstance();
    }
    if (mCountryChooseDialog.isAdded()) {　　//解決方法就是添加這行代碼，如果已經添加了，就移除掉然后再show，就不會出現Fragment already added的錯誤了。
      getSupportFragmentManager().beginTransaction().remove(mCountryChooseDialog).commit();
    }
    mCountryChooseDialog.show(getSupportFragmentManager(), mCountryChooseDialog.getClass().getName());
}