当宽度和高度设置为 0dp 时，回收站视图不呈现

Question

I have a simple layout, which contains a text view , ImageView , and a recycler view , If i set recycler's view width & height to 0dp, and connects its constraint to parent, it does not render the recycler view.

But if i define height in numbers then it works fine, and renders recyclerview

This is my code

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/blue"
    tools:context=".activities.MyActivityV2">

    <include layout="@layout/content_more_activity" />

</android.support.design.widget.CoordinatorLayout>

Inner Layout

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activities.MyActivityV2"
    tools:showIn="@layout/activity_more">

      <ImageView
        android:id="@+id/imageView23"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/logo" />


 <TextView
        android:id="@+id/tvLabelMore"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="12dp"
        android:layout_marginTop="10dp"
        android:letterSpacing="0.1"
        android:text="MORE"
        android:textAllCaps="true"
        android:textColor="@color/white"
        android:textSize="24dp"
        android:textStyle="bold"
        app:layout_constraintStart_toEndOf="@+id/imageView23"
        app:layout_constraintTop_toTopOf="parent" />


 <android.support.v7.widget.RecyclerView
        android:id="@+id/rvMoreItems"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constrainedHeight="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView23" />       

Class File

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


        init();
        generateDataForRecyclerView();
        initRecyclerView();
    }



    private void init() {

        rvMoreItems= findViewById(R.id.rvMoreItems);

    }


     private void generateDataForRecyclerView() {

        MoreDataClass moreDataClass= new MoreDataClass();
        moreDataClass.setLabel("AAA");
        moreDataClass.setHeaderItem(true);
        dataList.add(moreDataClass);

        dataList.add(moreDataClass);
}


    private void initRecyclerView() {

        MoreAdapter moreAdapter= new MoreAdapter(this);
        moreAdapter.setData(dataList);
        rvMoreItems.setLayoutManager(new LinearLayoutManager(this));
        rvMoreItems.setAdapter(moreAdapter);

    }

Answer 1

Update this function check below.

 private void initRecyclerView() {

        MoreAdapter moreAdapter= new MoreAdapter(this);
        rvMoreItems.setLayoutManager(new LinearLayoutManager(this));
        rvMoreItems.setAdapter(moreAdapter);
        moreAdapter.setData(dataList);

    }