小编kir*_*vel的帖子

当我尝试构建我的项目时，我遇到了这样一个错误：

FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:dataBindingGenBaseClassesDebug'.
> Parameter 'directory' is not a directory

我想使用 ViewBinding 来处理 Fragment 中的视图。

FragmentBlankBinding binding;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    binding = FragmentBlankBinding.inflate(inflater, container, false);
    return binding.getRoot();
}

但是当我尝试从这样的绑定中获取 RecyclerView 时：

binding.notesRecyclerView.setAdapter(adapter);

我得到空指针异常：

java.lang.NullPointerException：尝试从空对象引用上的字段“androidx.recyclerview.widget.RecyclerView com.myapps.notes.databinding.FragmentBlankBinding.notesRecyclerView”读取

PS这里是fragment_blank.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".BlankFragment">

    <com.getbase.floatingactionbutton.FloatingActionButton
        android:id="@+id/newNoteActionButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_margin="3dp"
        android:elevation="10dp"
        app:fab_icon="@drawable/ic_baseline_add_24" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/notesRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" /> 
</RelativeLayout>