PhotoViewGallery class

A StatefulWidget that shows multiple PhotoView widgets in a PageView

Some of PhotoView constructor options are passed direct to PhotoViewGallery constructor. Those options will affect the gallery in a whole.

Some of the options may be defined to each image individually, such as initialScale or PhotoViewHeroAttributes. Those must be passed via each PhotoViewGalleryPageOptions.

Example of usage as a list of options:

PhotoViewGallery(
  pageOptions: <PhotoViewGalleryPageOptions>[
    PhotoViewGalleryPageOptions(
      imageProvider: AssetImage("assets/gallery1.jpg"),
      heroAttributes: const PhotoViewHeroAttributes(tag: "tag1"),
    ),
    PhotoViewGalleryPageOptions(
      imageProvider: AssetImage("assets/gallery2.jpg"),
      heroAttributes: const PhotoViewHeroAttributes(tag: "tag2"),
      maxScale: PhotoViewComputedScale.contained * 0.3
    ),
    PhotoViewGalleryPageOptions(
      imageProvider: AssetImage("assets/gallery3.jpg"),
      minScale: PhotoViewComputedScale.contained * 0.8,
      maxScale: PhotoViewComputedScale.covered * 1.1,
      heroAttributes: const HeroAttributes(tag: "tag3"),
    ),
  ],
  loadingBuilder: (context, progress) => Center(
           child: Container(
             width: 20.0,
             height: 20.0,
             child: CircularProgressIndicator(
               value: _progress == null
                   ? null
                   : _progress.cumulativeBytesLoaded /
                       _progress.expectedTotalBytes,
             ),
           ),
         ),
  backgroundDecoration: widget.backgroundDecoration,
  pageController: widget.pageController,
  onPageChanged: onPageChanged,
)

Example of usage with builder pattern:

PhotoViewGallery.builder(
  scrollPhysics: const BouncingScrollPhysics(),
  builder: (BuildContext context, int index) {
    return PhotoViewGalleryPageOptions(
      imageProvider: AssetImage(widget.galleryItems[index].image),
      initialScale: PhotoViewComputedScale.contained * 0.8,
      minScale: PhotoViewComputedScale.contained * 0.8,
      maxScale: PhotoViewComputedScale.covered * 1.1,
      heroAttributes: HeroAttributes(tag: galleryItems[index].id),
    );
  },
  itemCount: galleryItems.length,
  loadingBuilder: (context, progress) => Center(
           child: Container(
             width: 20.0,
             height: 20.0,
             child: CircularProgressIndicator(
               value: _progress == null
                   ? null
                   : _progress.cumulativeBytesLoaded /
                       _progress.expectedTotalBytes,
             ),
           ),
         ),
  backgroundDecoration: widget.backgroundDecoration,
  pageController: widget.pageController,
  onPageChanged: onPageChanged,
)