How do I make WRAP_CONTENT work on a RecyclerView

Question

I have a DialogFragment that contains a RecyclerView (a list of cards).

Within this RecyclerView are one or more CardViews that can have any height.

I want to give this DialogFragment the correct height based on the CardViews that are contained within.

Normally this would be simple, I would set wrap_content on the RecyclerView like this.

<android.support.v7.widget.RecyclerView ...
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"   
    android:clickable="true"   
    android:scrollbars="vertical" >

</android.support.v7.widget.RecyclerView>

Because I am using a RecyclerView this does not work see:

https://issuetracker.google.com/issues/37001674

and

Nested Recycler view height doesn't wrap its content

On both of these pages people suggest to extend LinearLayoutManager and to override onMeasure()

I first used the LayoutManager that someone provided in the first link:

public static class WrappingLayoutManager extends LinearLayoutManager {

        public WrappingLayoutManager(Context context) {
            super(context);
        }

        private int[] mMeasuredDimension = new int[2];

        @Override
        public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                              int widthSpec, int heightSpec) {
            final int widthMode = View.MeasureSpec.getMode(widthSpec);
            final int heightMode = View.MeasureSpec.getMode(heightSpec);
            final int widthSize = View.MeasureSpec.getSize(widthSpec);
            final int heightSize = View.MeasureSpec.getSize(heightSpec);

            measureScrapChild(recycler, 0,
                    View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);

            int width = mMeasuredDimension[0];
            int height = mMeasuredDimension[1];

            switch (widthMode) {
                case View.MeasureSpec.EXACTLY:
                case View.MeasureSpec.AT_MOST:
                    width = widthSize;
                    break;
                case View.MeasureSpec.UNSPECIFIED:
            }

            switch (heightMode) {
                case View.MeasureSpec.EXACTLY:
                case View.MeasureSpec.AT_MOST:
                    height = heightSize;
                    break;
                case View.MeasureSpec.UNSPECIFIED:
            }

            setMeasuredDimension(width, height);
        }

        private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                       int heightSpec, int[] measuredDimension) {
            View view = recycler.getViewForPosition(position);
            if (view != null) {
                RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
                int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                        getPaddingLeft() + getPaddingRight(), p.width);
                int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                        getPaddingTop() + getPaddingBottom(), p.height);
                view.measure(childWidthSpec, childHeightSpec);
                measuredDimension[0] = view.getMeasuredWidth();
                measuredDimension[1] = view.getMeasuredHeight();
                recycler.recycleView(view);
            }
        }
    }

However this did not work because

heightSize = View.MeasureSpec.getSize(heightSpec);

returns a very large value that appear to be related to match_parent.

By commenting height = heightSize; (in the second switch case) I managed to make the height work but only if a TextView child inside the CardView does not wrap its own text (a long sentence).

As soon as that TextView wraps it's own text the height SHOULD increase but it doesn't. It calculated the height for that long sentence as a single line, not a wrapped line (2 or more).

Any advice on how I should improve this LayoutManager so my RecyclerView works with WRAP_CONTENT?

Edit: This layout manager might work for most people, but it still has problems with scrolling and calculating heights of wrapping textviews

public class MyLinearLayoutManager extends LinearLayoutManager {

public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
    super(context, orientation, reverseLayout);
}

private int[] mMeasuredDimension = new int[2];

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                      int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);
    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);
    int width = 0;
    int height = 0;
    for (int i = 0; i < getItemCount(); i++) {
        measureScrapChild(recycler, i,
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                mMeasuredDimension);

        if (getOrientation() == HORIZONTAL) {
            width = width + mMeasuredDimension[0];
            if (i == 0) {
                height = mMeasuredDimension[1];
            }
        } else {
            height = height + mMeasuredDimension[1];
            if (i == 0) {
                width = mMeasuredDimension[0];
            }
        }
    }
    switch (widthMode) {
        case View.MeasureSpec.EXACTLY:
            width = widthSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    switch (heightMode) {
        case View.MeasureSpec.EXACTLY:
            height = heightSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    setMeasuredDimension(width, height);
}

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

Answer 1

From Android Support Library 23.2.1 update, all WRAP_CONTENT should work correctly.

Please update version of a library in gradle file OR to further :

compile 'com.android.support:recyclerview-v7:23.2.1'

solved some issue like Fixed bugs related to various measure-spec methods

Check http://developer.android.com/tools/support-library/features.html#v7-recyclerview

you can check Support Library revision history