Kotlin 如何将软键盘隐藏在片段中

我有一个FragmentActivity，用ViewPager发了几个碎片.每个都是ListFragment，布局如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="8dp">
        <ListView android:id="@id/android:list"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />

        <EditText android:id="@+id/entertext"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>
</LinearLayout>

开始练习时，会显示软键盘.为了解决这个问题，我在片段中执行了以下操作:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    //Save the container view so we can access the window token
    viewContainer = container;
    //get the input method manager service
    imm = (InputMethodManager)getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
    . . .
}

@Override
public void onStart() {
    super.onStart();

    //Hide the soft keyboard
    imm.hideSoftInputFromWindow(viewContainer.getWindowToken(), 0);
}

I save the incoming ViewGroup container parameter from onCreateView as a way to access the window token for the main activity. This runs without error, but the keyboard doesn't get hidden from the call to hideSoftInputFromWindow in onStart.

最初，我try 使用充气布局而不是container，即:

imm.hideSoftInputFromWindow(myInflatedLayout.getWindowToken(), 0);

but this threw a NullPointerException, presumably because the fragment itself isn't an activity and doesn't have a unique window token?

有没有办法从片段中隐藏软键盘，或者我应该在FragmentActivity中创建一个方法，然后从片段中调用它？