appBar method

Widget appBar(BuildContext context)

AppBar widget. 顶栏部件

Implementation

Widget appBar(BuildContext context) {
  final bar = AssetPickerAppBar(
    leading: Semantics(
      sortKey: ordinalSortKey(0),
      child: IconButton(
        onPressed: () {
          Navigator.maybeOf(context)?.maybePop();
        },
        tooltip: MaterialLocalizations.of(context).backButtonTooltip,
        icon: Icon(
          Icons.arrow_back_ios_new,
          semanticLabel: MaterialLocalizations.of(context).backButtonTooltip,
        ),
      ),
    ),
    centerTitle: true,
    title: specialPickerType == null
        ? Semantics(
            sortKey: ordinalSortKey(0.1),
            child: StreamBuilder<int>(
              initialData: currentIndex,
              stream: pageStreamController.stream,
              builder: (_, AsyncSnapshot<int> snapshot) => ScaleText(
                '${snapshot.requireData + 1}/${previewAssets.length}',
                style: const TextStyle(
                  fontSize: 17,
                  fontWeight: FontWeight.w500,
                ),
              ),
            ),
          )
        : null,
    actions: [
      if (provider != null)
        Semantics(
          sortKey: ordinalSortKey(0.2),
          child: selectButton(context),
        ),
      const SizedBox(width: 14),
    ],
  );
  return ValueListenableBuilder(
    valueListenable: isDisplayingDetail,
    builder: (_, v, child) => AnimatedPositionedDirectional(
      duration: kThemeAnimationDuration,
      curve: Curves.easeInOut,
      top: v ? 0.0 : -(context.topPadding + bar.preferredSize.height),
      start: 0.0,
      end: 0.0,
      child: child!,
    ),
    child: bar,
  );
}