// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.chrome.browser.download.home.list;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.graphics.Rect;
import android.view.View;
import androidx.annotation.Nullable;
import androidx.core.view.ViewCompat;
import androidx.recyclerview.widget.DefaultItemAnimator;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.ItemDecoration;
import androidx.recyclerview.widget.RecyclerView.Recycler;
import androidx.recyclerview.widget.RecyclerView.State;
import org.chromium.chrome.browser.download.home.DownloadManagerUiConfig;
import org.chromium.chrome.browser.download.home.list.DateOrderedListCoordinator.DateOrderedListObserver;
import org.chromium.chrome.browser.download.home.list.ListItem.OfflineItemListItem;
import org.chromium.chrome.browser.download.home.list.holder.ListItemViewHolder;
import org.chromium.chrome.browser.download.internal.R;
import org.chromium.components.browser_ui.widget.displaystyle.HorizontalDisplayStyle;
import org.chromium.components.browser_ui.widget.displaystyle.UiConfig;
import org.chromium.ui.modelutil.ForwardingListObservable;
import org.chromium.ui.modelutil.PropertyModelChangeProcessor;
import org.chromium.ui.modelutil.RecyclerViewAdapter;
/**
* The View component of a DateOrderedList. This takes the DateOrderedListModel and creates the
* glue to display it on the screen.
*/
class DateOrderedListView {
private final DownloadManagerUiConfig mConfig;
private final DecoratedListItemModel mModel;
private final int mIdealImageWidthPx;
private final int mInterImagePaddingPx;
private final int mPrefetchVerticalPaddingPx;
private final int mHorizontalPaddingPx;
private final int mVerticalPaddingPx;
private final int mMaxWidthImageItemPx;
private final RecyclerView mView;
private final GridLayoutManager mGridLayoutManager;
private final UiConfig mUiConfig;
private Runnable mOnConfigurationChangedCallback;
/** Creates an instance of a {@link DateOrderedListView} representing {@code model}. */
public DateOrderedListView(
Context context,
DownloadManagerUiConfig config,
DecoratedListItemModel model,
DateOrderedListObserver dateOrderedListObserver,
Runnable onConfigurationChangedCallback) {
mConfig = config;
mModel = model;
mIdealImageWidthPx =
context.getResources()
.getDimensionPixelSize(R.dimen.download_manager_ideal_image_width);
mInterImagePaddingPx =
context.getResources()
.getDimensionPixelOffset(R.dimen.download_manager_image_padding);
mHorizontalPaddingPx =
context.getResources()
.getDimensionPixelSize(R.dimen.download_manager_horizontal_margin);
mPrefetchVerticalPaddingPx =
context.getResources()
.getDimensionPixelSize(R.dimen.download_manager_prefetch_vertical_margin);
mVerticalPaddingPx =
context.getResources()
.getDimensionPixelSize(
R.dimen.download_manager_vertical_margin_between_download_types);
mMaxWidthImageItemPx =
context.getResources()
.getDimensionPixelSize(
R.dimen.download_manager_max_image_item_width_wide_screen);
mView =
new RecyclerView(context) {
private int mScreenOrientation = Configuration.ORIENTATION_UNDEFINED;
@Override
protected void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mUiConfig.updateDisplayStyle();
if (newConfig.orientation == mScreenOrientation) return;
mScreenOrientation = newConfig.orientation;
mView.invalidateItemDecorations();
mOnConfigurationChangedCallback.run();
}
};
mView.setId(R.id.download_home_recycler_view);
mView.setHasFixedSize(true);
((DefaultItemAnimator) mView.getItemAnimator()).setSupportsChangeAnimations(false);
mView.getItemAnimator().setMoveDuration(0);
mGridLayoutManager = new GridLayoutManagerImpl(context);
mView.setLayoutManager(mGridLayoutManager);
mView.addItemDecoration(new ItemDecorationImpl());
mView.setClipToPadding(false);
PropertyModelChangeProcessor.create(
mModel.getProperties(), mView, new ListPropertyViewBinder());
// Do the final hook up to the underlying data adapter.
DateOrderedListViewAdapter adapter =
new DateOrderedListViewAdapter(
mModel, new ModelChangeProcessor(mModel), ListItemViewHolder::create);
mView.setAdapter(adapter);
mView.post(adapter::notifyDataSetChanged);
mView.addOnScrollListener(
new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView view, int dx, int dy) {
dateOrderedListObserver.onListScroll(mView.canScrollVertically(-1));
}
});
mUiConfig = new UiConfig(mView);
mUiConfig.addObserver(
(newDisplayStyle) -> {
int padding =
getPaddingForDisplayStyle(newDisplayStyle, context.getResources());
mView.setPaddingRelative(
padding, mView.getPaddingTop(), padding, mView.getPaddingBottom());
});
mOnConfigurationChangedCallback = onConfigurationChangedCallback;
}
/** @return The Android {@link View} representing this widget. */
public View getView() {
return mView;
}
/**
* @return The start and end padding of the recycler view for the given display style.
*/
private static int getPaddingForDisplayStyle(
UiConfig.DisplayStyle displayStyle, Resources resources) {
int padding = 0;
if (displayStyle.horizontal == HorizontalDisplayStyle.WIDE) {
int screenWidthDp = resources.getConfiguration().screenWidthDp;
padding =
(int)
(((screenWidthDp - UiConfig.WIDE_DISPLAY_STYLE_MIN_WIDTH_DP) / 2.f)
* resources.getDisplayMetrics().density);
padding =
(int)
Math.max(
resources.getDimensionPixelSize(
R.dimen
.download_manager_recycler_view_min_padding_wide_screen),
padding);
}
return padding;
}
/** @return The view width available after start and end padding. */
private int getAvailableViewWidth() {
return mView.getWidth()
- ViewCompat.getPaddingStart(mView)
- ViewCompat.getPaddingEnd(mView);
}
private class GridLayoutManagerImpl extends GridLayoutManager {
/** Creates an instance of a {@link GridLayoutManagerImpl}. */
public GridLayoutManagerImpl(Context context) {
super(context, /* spanCount= */ 1, VERTICAL, /* reverseLayout= */ false);
setSpanSizeLookup(new SpanSizeLookupImpl());
}
// GridLayoutManager implementation.
@Override
public void onLayoutChildren(Recycler recycler, State state) {
assert getOrientation() == VERTICAL;
int availableWidth = getAvailableViewWidth() - 2 * mHorizontalPaddingPx;
int columnWidth = mIdealImageWidthPx - mInterImagePaddingPx;
int easyFitSpan = availableWidth / columnWidth;
double remaining =
((double) (availableWidth - easyFitSpan * columnWidth)) / columnWidth;
if (remaining > 0.5) easyFitSpan++;
setSpanCount(Math.max(1, easyFitSpan));
super.onLayoutChildren(recycler, state);
}
@Override
public boolean supportsPredictiveItemAnimations() {
return false;
}
private class SpanSizeLookupImpl extends SpanSizeLookup {
// SpanSizeLookup implementation.
@Override
public int getSpanSize(int position) {
return ListUtils.getSpanSize(mModel.get(position), mConfig, getSpanCount());
}
}
}
private class ItemDecorationImpl extends ItemDecoration {
// ItemDecoration implementation.
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, State state) {
int position = parent.getChildAdapterPosition(view);
if (position < 0 || position >= mModel.size()) return;
ListItem item = mModel.get(position);
boolean isFullWidthMedia = false;
@ListUtils.ViewType
int viewType = ListUtils.getViewTypeForItem(mModel.get(position), mConfig);
switch (viewType) {
case ListUtils.ViewType.IMAGE: // fall through
case ListUtils.ViewType.IMAGE_FULL_WIDTH: // fall through
case ListUtils.ViewType.IN_PROGRESS_IMAGE:
isFullWidthMedia = ((ListItem.OfflineItemListItem) item).spanFullWidth;
if (isFullWidthMedia || mGridLayoutManager.getSpanCount() == 1) {
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
} else {
computeItemDecoration(position, outRect);
}
outRect.top = mInterImagePaddingPx / 2;
outRect.bottom = mInterImagePaddingPx / 2;
break;
case ListUtils.ViewType.VIDEO: // Intentional fallthrough.
case ListUtils.ViewType.IN_PROGRESS_VIDEO:
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
outRect.top = mPrefetchVerticalPaddingPx / 2;
outRect.bottom = mPrefetchVerticalPaddingPx / 2;
isFullWidthMedia = true;
break;
case ListUtils.ViewType.PREFETCH_ARTICLE: // fall through
case ListUtils.ViewType.AUDIO:
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
outRect.top = mPrefetchVerticalPaddingPx / 2;
outRect.bottom = mPrefetchVerticalPaddingPx / 2;
break;
case ListUtils.ViewType.GROUP_CARD_HEADER: // fall through
case ListUtils.ViewType.GROUP_CARD_FOOTER: // fall through
case ListUtils.ViewType.GROUP_CARD_ITEM: // fall through
case ListUtils.ViewType.GROUP_CARD_DIVIDER_MIDDLE:
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
break;
case ListUtils.ViewType.GROUP_CARD_DIVIDER_TOP:
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
outRect.top = mPrefetchVerticalPaddingPx / 2;
break;
case ListUtils.ViewType.GROUP_CARD_DIVIDER_BOTTOM:
outRect.left = mHorizontalPaddingPx;
outRect.right = mHorizontalPaddingPx;
outRect.bottom = mPrefetchVerticalPaddingPx / 2;
break;
}
if (isFullWidthMedia
&& mUiConfig.getCurrentDisplayStyle().horizontal
== HorizontalDisplayStyle.WIDE) {
outRect.right += Math.max(getAvailableViewWidth() - mMaxWidthImageItemPx, 0);
}
// If the current item is the last of its download type in a given section and not
// displayed in a grid, add padding below. Grid items are handled differently as
// described in the next section.
if (isLastOfDownloadTypeInSection(position) && !(isGridItem(position))) {
outRect.bottom += mVerticalPaddingPx;
}
// If the previous item was a grid item, and current one is not, add padding above to
// differentiate between sections.
if (position > 0
&& isLastOfDownloadTypeInSection(position - 1)
&& isGridItem(position - 1)) {
outRect.top += mVerticalPaddingPx;
}
}
private void computeItemDecoration(int position, Rect outRect) {
GridLayoutManager.SpanSizeLookup spanLookup = mGridLayoutManager.getSpanSizeLookup();
int spanCount = mGridLayoutManager.getSpanCount();
int columnIndex = spanLookup.getSpanIndex(position, spanCount);
horizontallyRepositionGridItem(
columnIndex,
spanCount,
mHorizontalPaddingPx,
mHorizontalPaddingPx,
mInterImagePaddingPx,
outRect);
}
}
/**
* Given the column index for an image in a grid view, computes the left and right edge
* offsets.
* @param columnIndex Column index for the item
* @param spanCount Span count of the grid
* @param leftMargin Leftmost margin in the row
* @param rightMargin Rightmost margin in the row
* @param padding Spacing between two items
* @param outRect The output rect that contains the computed offsets
*/
private static void horizontallyRepositionGridItem(
int columnIndex,
int spanCount,
int leftMargin,
int rightMargin,
int padding,
Rect outRect) {
assert spanCount > 1;
// Margin here refers to the leftmost or rightmost margin in the row, and padding here
// refers to the inter-image spacing.
// Calculate how much each image should be shrunk compared to the ideal image size if no
// margin or padding were present.
int shrink = (leftMargin + rightMargin + (spanCount - 1) * padding) / spanCount;
// Starting from left, calculate how much the image is shifted from ideal position
// due to the leftmost margin and padding between previous images. Subtract the
// total shrink for the previous images from this value.
outRect.left = leftMargin + columnIndex * padding - columnIndex * shrink;
// For right edge, the calculation is exactly same as left, except we have one extra
// shrink. Negate the final value.
outRect.right = -(leftMargin + columnIndex * padding - (columnIndex + 1) * shrink);
}
/**
* Determines whether or not the item at position is an OfflineItemListItem (representing a
* downloaded item) and is the last of its type in a given section. Does so by comparing the
* current item to the following item.
* @param position Index of the item we are checking
* @return Whether or not the current item is the last of its download type in a given section.
*/
private boolean isLastOfDownloadTypeInSection(int position) {
// If the current item is not an OfflineItemListItem, it cannot have a download type, and
// thus can't be the last of its download type.
ListItem currentItem = mModel.get(position);
if (!(currentItem instanceof OfflineItemListItem)) return false;
// If the next item is not an OfflineItemListItem, it cannot have a download type. This
// means the next item can't be the same type as the current item and the current item is
// therefore the last of its download type.
ListItem nextItem = position >= mModel.size() - 1 ? null : mModel.get(position + 1);
if (!(nextItem instanceof OfflineItemListItem)) return true;
// If both items are OfflineItemListItems, but are of different type, then the current item
// is the last of its type.
boolean nextItemIsDifferentType =
((OfflineItemListItem) currentItem).item.filter
!= ((OfflineItemListItem) nextItem).item.filter;
if (nextItemIsDifferentType) return true;
// If this point is reached, both items are OfflineListItems and the same type, meaning the
// current item is not the last of its type.
return false;
}
/**
* Determines whether or not the item at position is displayed in a grid (e.g. multiple images).
* Does so by checking if the item's span size is less than the span count of a row.
* @param position Index of the item we are checking
* @return Whether or not the item at position is displayed in a grid.
*/
private boolean isGridItem(int position) {
GridLayoutManager.SpanSizeLookup spanLookup = mGridLayoutManager.getSpanSizeLookup();
int spanCount = mGridLayoutManager.getSpanCount();
int spanSize = spanLookup.getSpanSize(position);
return spanSize < spanCount;
}
private class ModelChangeProcessor extends ForwardingListObservable<Void>
implements RecyclerViewAdapter.Delegate<ListItemViewHolder, Void> {
private final DecoratedListItemModel mModel;
public ModelChangeProcessor(DecoratedListItemModel model) {
mModel = model;
model.addObserver(this);
}
@Override
public int getItemCount() {
return mModel.size();
}
@Override
public int getItemViewType(int position) {
return ListUtils.getViewTypeForItem(mModel.get(position), mConfig);
}
@Override
public void onBindViewHolder(
ListItemViewHolder viewHolder, int position, @Nullable Void payload) {
viewHolder.bind(mModel.getProperties(), mModel.get(position));
}
@Override
public void onViewRecycled(ListItemViewHolder viewHolder) {
viewHolder.recycle();
}
}
}
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