bottomDetailItemBuilder method

@override Widget bottomDetailItemBuilder(BuildContext context, int index)

Thumb item widgets in bottom detail. 底部信息栏单个资源缩略部件

Implementation

@override
Widget bottomDetailItemBuilder(BuildContext context, int index) {
  const double padding = 8.0;

  void onTap(AssetEntity asset) {
    final int page;
    if (previewAssets != selectedAssets) {
      page = previewAssets.indexOf(asset);
    } else {
      page = index;
    }
    if (pageController.page == page.toDouble()) {
      return;
    }
    pageController.jumpToPage(page);
    final double offset =
        (index - 0.5) * (bottomPreviewHeight - padding * 3) -
            context.mediaQuery.size.width / 4;
    previewingListController.animateTo(
      math.max(0, offset),
      curve: Curves.ease,
      duration: kThemeChangeDuration,
    );
  }

  return Padding(
    padding: const EdgeInsets.symmetric(
      horizontal: padding,
      vertical: padding * 2,
    ),
    child: AspectRatio(
      aspectRatio: 1.0,
      child: StreamBuilder<int>(
        initialData: currentIndex,
        stream: pageStreamController.stream,
        builder: (_, AsyncSnapshot<int> snapshot) {
          final AssetEntity asset = selectedAssets!.elementAt(index);
          final bool isViewing = previewAssets[snapshot.data!] == asset;
          final Widget item = () {
            switch (asset.type) {
              case AssetType.image:
                return _imagePreviewItem(asset);
              case AssetType.video:
                return _videoPreviewItem(asset);
              case AssetType.audio:
                return _audioPreviewItem(asset);
              case AssetType.other:
                return const SizedBox.shrink();
            }
          }();
          return Semantics(
            label: '${semanticsTextDelegate.semanticTypeLabel(asset.type)}'
                '${index + 1}',
            selected: isViewing,
            onTap: () => onTap(asset),
            onTapHint: semanticsTextDelegate.sActionPreviewHint,
            excludeSemantics: true,
            child: GestureDetector(
              onTap: () => onTap(asset),
              child: Selector<AssetPickerViewerProvider<AssetEntity>?,
                  List<AssetEntity>?>(
                selector: (_, AssetPickerViewerProvider<AssetEntity>? p) =>
                    p?.currentlySelectedAssets,
                child: item,
                builder: (
                  _,
                  List<AssetEntity>? currentlySelectedAssets,
                  Widget? w,
                ) {
                  final bool isSelected =
                      currentlySelectedAssets?.contains(asset) ?? false;
                  return Stack(
                    children: <Widget>[
                      w!,
                      AnimatedContainer(
                        duration: kThemeAnimationDuration,
                        curve: Curves.easeInOut,
                        decoration: BoxDecoration(
                          border: isViewing
                              ? Border.all(
                                  color: themeData.colorScheme.secondary,
                                  width: 3,
                                )
                              : null,
                          color: isSelected
                              ? null
                              : themeData.colorScheme.surface
                                  .withOpacity(0.54),
                        ),
                      ),
                    ],
                  );
                },
              ),
            ),
          );
        },
      ),
    ),
  );
}