Error using the RecyclerView: The specified child already has a parent

Question

I am trying to create a listView with a new RecyvlerView Adapter. I have followed the exact guide present on android developer resources. But this is giving me a strange err

Answer 1

It happens too if you scroll really fast your recyclerview. My case was inserting/moving/... items with DiffUtils and calling TransitionManager.beginDelayedTransition(view) on the root layout (and so, the recyclerview) somewhere in my code before the end of recyclerview animations

Answer 2

when inflating you shouldn't attach the view to its parent. you wrote:

View v = inflater.inflate(R.layout.my_text_view, parent, true);

which should be :

View v = inflater.inflate(R.layout.my_text_view, parent, false);

Answer 3

For those wondering how to implement custom Transitions & excludeChildren method. Here's my approach looks like so far.

In Kotlin: TransitionHelpers.kt

// single child
private fun useAutoTransition(childView: View, 
                               excludeChildView: Boolean = true
) = AutoTransition().apply {
    excludeChildren(childView, excludeChildView)
    // apply any other method you need here
}

private fun useAutoTransition(@IdRes childViewId: Int, 
                               excludeChildView: Boolean = true
) = AutoTransition().apply {
    excludeChildren(childViewId, excludeChildView)
    // apply any other method you need here
}

// multiple child
fun useAutoTransitions(excludeChildView: Boolean, @IdRes vararg childViewIds: Int) {
        val auto = AutoTransition();

        for (id in childViewIds) {
           auto.excludeChildren(id, excludeChildView)
        }

        return auto;
    }

fun useAutoTransitions(excludeChildView: Boolean, vararg childViews: View) {
        val auto = AutoTransition();

        for (view in childViews) {
           auto.excludeChildren(view, excludeChildView)
        }

        return auto;
    }

In Java: TransitionHelpers.java

I'm using android-retrostream to support Android API below 24, and still using Java 8 lambda & java.util.* -> java9.util.*

import java9.util.stream.Stream;

    public static AutoTransition useAutoTransition(View childView, boolean excludeChildView) {
        AutoTransition auto = new AutoTransition();
        auto.excludeChildren(childView, excludeChildView);

        return auto;
    }

    public static AutoTransition useAutoTransition(@IdRes int childViewId, boolean excludeChildView) {
        AutoTransition auto = new AutoTransition();
        auto.excludeChildren(childViewId, excludeChildView);

        return auto;
    }

    public static AutoTransition useAutoTransitions(final boolean excludeChildView, @IdRes Integer... childViewIds) {
        final AutoTransition auto = new AutoTransition();

        Stream<Integer> ids = Stream.of(childViewIds);
        ids.forEach(id -> auto.excludeChildren(id, excludeChildView));

        return auto;
    }

    public static AutoTransition useAutoTransitions(final boolean excludeChildView, View... childViews) {
        final AutoTransition auto = new AutoTransition();

        Stream<View> views = Stream.of(childViews);
        views.forEach(view -> auto.excludeChildren(view, excludeChildView));

        return auto;
    }

ThatFragment.kt

// I'm using KTX Syntethic here
import kotlinx.android.synthetic.main.activity_transitions.layoutParent
import kotlinx.android.synthetic.main.activity_transitions.recyclerViewChild

// Let's implemented it on TransitionManager
override protected fun onCreate(savedInstanceState: Bundle) {
  // single RecyclerView child using View class
  TransitionManager.beginDelayedTransition(layoutParent, useAutoTransition(recyclerViewChild, true))

  // single RecyclerView child using @IdRes
  TransitionManager.beginDelayedTransition(layoutParent, useAutoTransition(R.id.rv_1, true))

  // multiple RecyclerView child                         
  TransitionManager.beginDelayedTransition(layoutParent, useAutoTransitions(true, R.id.rv_child_1, R.id.rv_child_2, R.id.rv_child_n))
}

Hopefully, it's easy to understand!

Thanks for:

• @victor Transitions problems when scrolling too fast
• @westy92 Providing the workaround & implement custom Transitions

References:

• Animate all the things (Transitions)
• Implementing excludeChildren see here
• Beautiful animation with ConstraintLayout & TransitionManager

Answer 4

Maybe it's a little bit late, but I had the same problem (recyclerview-v7:26.1.0) and the reason was that I tried to scroll (by scrollToPosition() method) the list in a position that was currently visible. After I added a check of position before scrolling (scroll only in the invisible position) the issue was resolved

Answer 5

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="80dp">

<TextView
    android:id="@+id/item_title"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textColor="@android:color/darker_gray"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginTop="8dp"
    android:textSize="22dp" />

</RelativeLayout>

RelativeLayout this is parent of your TextView with id item_title. Then when RecyclerView is trying to add TextView that has parent it throw exception.

Try this code:

public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                   int viewType) {
        // create a new view
        Log.d(TAG, "onCreateViewHolder");
        RelativeLayout v = (RelativeLayout)LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_item, parent, false);
        // set the view's size, margins, paddings and layout parameters
        View view = v.findViewById(R.id.text1);
        v.removeView(view);
        ViewHolder vh = new ViewHolder(view);
        return vh;
    }

Answer 6

I solved it by removing `TransitionManager.beginDelayedTransition();