selectButton method

@override Widget selectButton(BuildContext context)

Select button. 选择按钮

Implementation

@override
Widget selectButton(BuildContext context) {
  return CNP<AssetPickerViewerProvider<AssetEntity>>.value(
    value: provider!,
    builder: (_, Widget? w) => StreamBuilder<int>(
      initialData: currentIndex,
      stream: pageStreamController.stream,
      builder: (_, s) {
        final index = s.data!;
        final assetIndex =
            shouldReversePreview ? previewAssets.length - index - 1 : index;
        if (assetIndex < 0) {
          throw IndexError.withLength(
            assetIndex,
            previewAssets.length,
            indexable: previewAssets,
            name: 'selectButton.assetIndex',
            message: 'previewReversed: $shouldReversePreview\n'
                'stream.index: $index\n'
                'selectedAssets.length: ${selectedAssets?.length}\n'
                'previewAssets.length: ${previewAssets.length}\n'
                'currentIndex: $currentIndex\n'
                'maxAssets: $maxAssets',
          );
        }
        final asset = previewAssets.elementAt(assetIndex);
        return Selector<AssetPickerViewerProvider<AssetEntity>,
            List<AssetEntity>>(
          selector: (_, p) => p.currentlySelectedAssets,
          builder: (context, assets, _) {
            final bool isSelected = assets.contains(asset);
            return Semantics(
              selected: isSelected,
              label: semanticsTextDelegate.select,
              onTap: () {
                onChangingSelected(context, asset, isSelected);
              },
              onTapHint: semanticsTextDelegate.select,
              excludeSemantics: true,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: <Widget>[
                  if (isAppleOS(context))
                    _appleOSSelectButton(context, isSelected, asset)
                  else
                    _androidSelectButton(context, isSelected, asset),
                  if (!isAppleOS(context))
                    ScaleText(
                      textDelegate.select,
                      style: const TextStyle(fontSize: 17, height: 1.2),
                      semanticsLabel: semanticsTextDelegate.select,
                    ),
                ],
              ),
            );
          },
        );
      },
    ),
  );
}