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Décorer RecyclerView (avec GridLayoutManager) pour afficher un séparateur entre les éléments

Quelle est la meilleure façon et la plus simple de décorer RecyclerView pour obtenir un tel aspect?

enter image description here

Le principal défi ici est de séparer uniquement les éléments, mais pas entre les éléments et les bordures gauche/droite de l’écran.

Des idées?

androidandroid-recyclerview
33
AlexKorovyansky

Je ne sais pas pourquoi vous en avez besoin, mais cette interface utilisateur est assez facile à mettre en œuvre avec RecyclerView Decorator.

mRecylerView.addItemDecoration(new ItemDecorationAlbumColumns(
    getResources().getDimensionPixelSize(R.dimen.photos_list_spacing), 
    getResources().getInteger(R.integer.photo_list_preview_columns)));

et décorateur (a besoin d'un peu de rafraichissement)

import Android.graphics.Rect;
import Android.support.v7.widget.RecyclerView;
import Android.view.View;

public class ItemDecorationAlbumColumns extends RecyclerView.ItemDecoration {

    private int mSizeGridSpacingPx;
    private int mGridSize;

    private boolean mNeedLeftSpacing = false;

    public ItemDecorationAlbumColumns(int gridSpacingPx, int gridSize) {
        mSizeGridSpacingPx = gridSpacingPx;
        mGridSize = gridSize;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int frameWidth = (int) ((parent.getWidth() - (float) mSizeGridSpacingPx * (mGridSize - 1)) / mGridSize);
        int padding = parent.getWidth() / mGridSize - frameWidth;
        int itemPosition = ((RecyclerView.LayoutParams) view.getLayoutParams()).getViewAdapterPosition();
        if (itemPosition < mGridSize) {
            outRect.top = 0;
        } else {
            outRect.top = mSizeGridSpacingPx;
        }
        if (itemPosition % mGridSize == 0) {
            outRect.left = 0;
            outRect.right = padding;
            mNeedLeftSpacing = true;
        } else if ((itemPosition + 1) % mGridSize == 0) {
            mNeedLeftSpacing = false;
            outRect.right = 0;
            outRect.left = padding;
        } else if (mNeedLeftSpacing) {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx - padding;
            if ((itemPosition + 2) % mGridSize == 0) {
                outRect.right = mSizeGridSpacingPx - padding;
            } else {
                outRect.right = mSizeGridSpacingPx / 2;
            }
        } else if ((itemPosition + 2) % mGridSize == 0) {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx / 2;
            outRect.right = mSizeGridSpacingPx - padding;
        } else {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx / 2;
            outRect.right = mSizeGridSpacingPx / 2;
        }
        outRect.bottom = 0;
    }
}

enter image description hereenter image description here

93
Dmitry L.

Vous pouvez avoir votre réponse mais je poste toujours ma solution qui peut aider les autres. Ceci peut être utilisé pour les listes verticales, horizontales ou les vues de grille en transmettant l'orientation.

import Android.content.Context;
import Android.content.res.TypedArray;
import Android.graphics.Canvas;
import Android.graphics.Rect;
import Android.graphics.drawable.Drawable;
import Android.support.v7.widget.LinearLayoutManager;
import Android.support.v7.widget.RecyclerView;
import Android.view.View;

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[]{
            Android.R.attr.listDivider
    };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
    public static final int GRID = 2;

    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST && orientation != GRID) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else if(mOrientation == HORIZONTAL_LIST){
            drawHorizontal(c, parent);
        } else {
            drawVertical(c, parent);
            drawHorizontal(c, parent);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        if (parent.getChildCount() == 0) return;

        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final View child = parent.getChildAt(0);
        if (child.getHeight() == 0) return;

        final RecyclerView.LayoutParams params =
                (RecyclerView.LayoutParams) child.getLayoutParams();
        int top = child.getBottom() + params.bottomMargin + mDivider.getIntrinsicHeight();
        int bottom = top + mDivider.getIntrinsicHeight();

        final int parentBottom = parent.getHeight() - parent.getPaddingBottom();
        while (bottom < parentBottom) {
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);

            top += mDivider.getIntrinsicHeight() + params.topMargin + child.getHeight() + params.bottomMargin + mDivider.getIntrinsicHeight();
            bottom = top + mDivider.getIntrinsicHeight();
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params =
                    (RecyclerView.LayoutParams) child.getLayoutParams();
            final int left = child.getRight() + params.rightMargin + mDivider.getIntrinsicHeight();
            final int right = left + mDivider.getIntrinsicWidth();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else if(mOrientation == HORIZONTAL_LIST) {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), mDivider.getIntrinsicHeight());
        }
    }
}
5
Nauman Zubair

Voici une implémentation plus simple et plus conviviale:

public class MediaSpaceDecoration extends RecyclerView.ItemDecoration {
    private final int spacing;
    private final List<Integer> allowedViewTypes = Arrays.asList(
            R.layout.item_image,
            R.layout.item_blur);

    public MediaSpaceDecoration(int spacing) {
        this.spacing = spacing;
    }

    @Override
    public void getItemOffsets(Rect outRect,
                               View view,
                               RecyclerView parent,
                               RecyclerView.State state) {
        final int position = parent.getChildAdapterPosition(view);
        if (!isMedia(parent, position)) {
            return;
        }

        final int totalSpanCount = getTotalSpanCount(parent);
        int spanSize = getItemSpanSize(parent, position);
        if (totalSpanCount == spanSize) {
            return;
        }

        outRect.top = isInTheFirstRow(position, totalSpanCount) ? 0 : spacing;
        outRect.left = isFirstInRow(position, totalSpanCount) ? 0 : spacing / 2;
        outRect.right = isLastInRow(position, totalSpanCount) ? 0 : spacing / 2;
        outRect.bottom = 0; // don't need
    }

    private boolean isInTheFirstRow(int position, int spanCount) {
        return position < spanCount;
    }

    private boolean isFirstInRow(int position, int spanCount) {
        return position % spanCount == 0;
    }

    private boolean isLastInRow(int position, int spanCount) {
        return isFirstInRow(position + 1, spanCount);
    }

    private int getTotalSpanCount(RecyclerView parent) {
        final RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        return layoutManager instanceof GridLayoutManager
            ? ((GridLayoutManager) layoutManager).getSpanCount()
            : 1;
    }

    private int getItemSpanSize(RecyclerView parent, int position) {
        final RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        return layoutManager instanceof GridLayoutManager
            ? ((GridLayoutManager) layoutManager).getSpanSizeLookup().getSpanSize(position)
            : 1;
    }

    private boolean isMedia(RecyclerView parent, int viewPosition) {
        final RecyclerView.Adapter adapter = parent.getAdapter();
        final int viewType = adapter.getItemViewType(viewPosition);
        return allowedViewTypes.contains(viewType);
    }
}

Je vérifie également avant de définir le outRect car j’ai plusieurs spanSizes pour chaque viewType et j’ai besoin d’ajouter un espace intermédiaire supplémentaire uniquement pour allowedViewTypes. Vous pouvez facilement supprimer cette vérification et le code serait encore plus simple. Cela ressemble à ceci pour moi:  GridLayout with a different spanSize for each viewType

5
Nikolay Kulachenko
  @BindingAdapter({"bind:adapter"})
    public static void bind(RecyclerView view, RecyclerView.Adapter<BaseViewHolder> adapter) {
        view.setLayoutManager(new GridLayoutManager(view.getContext(), 3));
        view.addItemDecoration(new SpacesItemDecorationGrid(view.getContext(), 4, 3));
        view.setItemAnimator(new DefaultItemAnimator());
        view.setAdapter(adapter);
    }


public class SpacesItemDecorationGrid extends RecyclerView.ItemDecoration {

    private int mSizeGridSpacingPx;
    private int mGridSize;
    private boolean mNeedLeftSpacing = false;

    /**
     * @param gridSpacingPx
     * @param gridSize
     */
    SpacesItemDecorationGrid(Context context, int gridSpacingPx, int gridSize) {
        mSizeGridSpacingPx = (int) Util.convertDpToPixel(gridSpacingPx, context);
        mGridSize = gridSize;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int frameWidth = (int) ((parent.getWidth() - (float) mSizeGridSpacingPx * (mGridSize - 1)) / mGridSize);
        int padding = parent.getWidth() / mGridSize - frameWidth;
        int itemPosition = ((RecyclerView.LayoutParams) view.getLayoutParams()).getViewAdapterPosition();
        int itemCount = parent.getAdapter().getItemCount() - mGridSize;


   /*     if (itemPosition < mGridSize) {
            outRect.top = mSizeGridSpacingPx;
        } else {
                   outRect.top = mSizeGridSpacingPx;
        }*/
        outRect.top = mSizeGridSpacingPx;
        if (itemPosition % mGridSize == 0) {
            outRect.left = mSizeGridSpacingPx;
            outRect.right = padding;
            mNeedLeftSpacing = true;
        } else if ((itemPosition + 1) % mGridSize == 0) {
            mNeedLeftSpacing = false;
            outRect.right = mSizeGridSpacingPx;
            outRect.left = padding;
        } else if (mNeedLeftSpacing) {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx - padding;
            if ((itemPosition + 2) % mGridSize == 0) {
                outRect.right = mSizeGridSpacingPx - padding;
            } else {
                outRect.right = mSizeGridSpacingPx / 2;
            }
        } else if ((itemPosition + 2) % mGridSize == 0) {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx / 2;
            outRect.right = mSizeGridSpacingPx - padding;
        } else {
            mNeedLeftSpacing = false;
            outRect.left = mSizeGridSpacingPx / 2;
            outRect.right = mSizeGridSpacingPx / 2;
        }
        if (itemPosition > itemCount) {
            outRect.bottom = mSizeGridSpacingPx;
        } else {
            outRect.bottom = 0;
        }

    }

}
0
Dhaval Joshi

Une solution plus simple qui a fonctionné pour moi. J'espère que cela peut être utile.

class GridItemDecorator(val context: Context, private val spacingDp: Int, private val mGridSize: Int) : RecyclerView.ItemDecoration() {

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {

        val resources = context.resources
        val spacingPx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, spacingDp.toFloat(), resources.displayMetrics)

        val bit = if (spacingPx > mGridSize) Math.round(spacingPx / mGridSize) else 1
        val itemPosition = (view.layoutParams as RecyclerView.LayoutParams).viewAdapterPosition

        outRect.top = if (itemPosition < mGridSize) 0 else  bit * mGridSize
        outRect.bottom = 0

        val rowPosition = itemPosition % mGridSize
        outRect.left = rowPosition * bit
        outRect.right = (mGridSize - rowPosition - 1) * bit

    }
}
0
AlexKost