android - findViewById 在 include 的内部 View 上返回 null

Question

我有类似的问题，比如这个线程 findViewById returns null on a LinearLayout inside an <include>d view

我也有类似的问题:

调用 include block 的 xml:

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            ...>
    <include  
                android:id="@+id/popupMenu"
                layout="@layout/mainmenu_popup" /> 
    </RelativeLayout>

和包含所包含代码的mainmenu_popup.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:visibility="gone"
        android:layout_marginTop="@dimen/action_bar_height"
        android:layout_width="0dp"
        android:layout_height="0dp">
      <fragment
        android:id="@+id/mainmenupopup_fragment"
        class="RetailMobile.MainMenuFragment" />
    <TextView
            android:layout_width="fill_parent"
            android:layout_height="1dp"
            android:layout_below="@id/mainmenupopup_fragment" 
            android:background="@color/dark_blue"
            android:id="@+id/blueLine" />
    <RelativeLayout
        ...
    </RelativeLayout>
</RelativeLayout>

我关注 Luksprog 的回答

RelativeLayout popupMenu = this.Activity.FindViewById<RelativeLayout>(Resource.Id.popupMenu);

但是 popupMenu == null

我还检查了这个线程findViewById not working for an include?没有积极的结果。

Answer 1

将android:id添加到mainmenu_popup.xml中的RelativeLayout，然后通过其中定义的id查找 View