问题
I have a custom fragment which is attached to my MainActivity. The layout file of the fragment contains the recyclerview widget.
fragment_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"/>
</FrameLayout>
Within my RecyclerView.Adapter the onCreateViewHolder method looks like this:
@Override
public MyAdapter.MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout
.list_item, parent, false);
return new MyHolder(view);
}
My question is about the Viewgroup parent from this method. This ViewGroup is my RecyclerView widget but why gives me parent.getContext a reference to my MainActivity and not to my fragment?
回答1:
Fragments do not really have a context. When working in a fragment and you need a context, normally you need to call getActivity()
. In this specific case, the context is passed down from the activity to the fragment to the RecyclerView - remember a view takes a context in it's constructor - and so when you call getContext()
on the RecyclerView (the ViewGroup) it returns the activity.
来源:https://stackoverflow.com/questions/30605133/parent-getcontext-within-recyclerview-adapters-oncreateviewholder-method