remove loading child (#307)

Author: renancaraujo

lib/photo_view.dart

@@ -238,7 +238,6 @@ class PhotoView extends StatefulWidget {
   PhotoView({
     Key key,
     @required this.imageProvider,
-    @Deprecated("Use loadingBuilder instead") this.loadingChild,
     this.loadingBuilder,
     this.loadFailedChild,
     this.backgroundDecoration,
@@ -294,16 +293,12 @@ class PhotoView extends StatefulWidget {
         imageProvider = null,
         gaplessPlayback = false,
         loadingBuilder = null,
-        loadingChild = null,
         super(key: key);
 
   /// Given a [imageProvider] it resolves into an zoomable image widget using. It
   /// is required
   final ImageProvider imageProvider;
 
-  /// You should now use loadingBuilder(context, progress) => widget
-  final Widget loadingChild;
-
   /// While [imageProvider] is not resolved, [loadingBuilder] is called by [PhotoView]
   /// into the screen, by default it is a centered [CircularProgressIndicator]
   final LoadingBuilder loadingBuilder;
@@ -622,10 +617,6 @@ class _PhotoViewState extends State<PhotoView> {
       return widget.loadingBuilder(context, _imageChunkEvent);
     }
 
-    if (widget.loadingChild != null) {
-      return widget.loadingChild;
-    }
-
     return PhotoViewDefaultLoading(
       event: _imageChunkEvent,
     );

lib/photo_view_gallery.dart

@@ -102,7 +102,6 @@ class PhotoViewGallery extends StatefulWidget {
   const PhotoViewGallery({
     Key key,
     @required this.pageOptions,
-    @Deprecated("Use loadingBuilder instead") this.loadingChild,
     this.loadingBuilder,
     this.loadFailedChild,
     this.backgroundDecoration,
@@ -115,8 +114,7 @@ class PhotoViewGallery extends StatefulWidget {
     this.scrollPhysics,
     this.scrollDirection = Axis.horizontal,
     this.customSize,
-  })  : _isBuilder = false,
-        itemCount = null,
+  })  : itemCount = null,
         builder = null,
         assert(pageOptions != null),
         super(key: key);
@@ -128,7 +126,6 @@ class PhotoViewGallery extends StatefulWidget {
     Key key,
     @required this.itemCount,
     @required this.builder,
-    @Deprecated("Use loadingBuilder instead") this.loadingChild,
     this.loadingBuilder,
     this.loadFailedChild,
     this.backgroundDecoration,
@@ -141,8 +138,7 @@ class PhotoViewGallery extends StatefulWidget {
     this.scrollPhysics,
     this.scrollDirection = Axis.horizontal,
     this.customSize,
-  })  : _isBuilder = true,
-        pageOptions = null,
+  })  : pageOptions = null,
         assert(itemCount != null),
         assert(builder != null),
         super(key: key);
@@ -162,9 +158,6 @@ class PhotoViewGallery extends StatefulWidget {
   /// Mirror to [PhotoView.loadingBuilder]
   final LoadingBuilder loadingBuilder;
 
-  /// Mirror to [PhotoView.loadingchild]
-  final Widget loadingChild;
-
   /// Mirror to [PhotoView.loadFailedChild]
   final Widget loadFailedChild;
 
@@ -195,7 +188,7 @@ class PhotoViewGallery extends StatefulWidget {
   /// The axis along which the [PageView] scrolls. Mirror to [PageView.scrollDirection]
   final Axis scrollDirection;
 
-  final bool _isBuilder;
+  bool get _isBuilder => builder != null;
 
   @override
   State<StatefulWidget> createState() {
@@ -277,7 +270,6 @@ class _PhotoViewGalleryState extends State<PhotoViewGallery> {
             key: ObjectKey(index),
             imageProvider: pageOption.imageProvider,
             loadingBuilder: widget.loadingBuilder,
-            loadingChild: widget.loadingChild,
             loadFailedChild: widget.loadFailedChild,
             backgroundDecoration: widget.backgroundDecoration,
             controller: pageOption.controller,