✨ Introduce Gap and SliverGap

Author: AlexV525

lib/src/constants/constants.dart

@@ -28,6 +28,7 @@ export '../widget/builder/fade_image_builder.dart';
 export '../widget/builder/image_page_builder.dart';
 export '../widget/builder/video_page_builder.dart';
 export '../widget/fixed_appbar.dart';
+export '../widget/gaps.dart';
 export '../widget/platform_progress_indicator.dart';
 
 export 'colors.dart';

lib/src/widget/gaps.dart

@@ -0,0 +1,75 @@
+///
+/// [Author] Alex (https://github.com/AlexV525)
+/// [Date] 2020/10/27 17:14
+///
+import 'package:flutter/material.dart';
+
+class Gap extends StatelessWidget {
+  const Gap.h(
+    double width, {
+    Key? key,
+    double? height,
+    this.color,
+  })  : _width = width,
+        _height = height,
+        super(key: key);
+
+  const Gap.v(
+    double height, {
+    Key? key,
+    double? width,
+    this.color,
+  })  : _width = width,
+        _height = height,
+        super(key: key);
+
+  final double? _width;
+  final double? _height;
+  final Color? color;
+
+  @override
+  Widget build(BuildContext context) {
+    Widget _w = SizedBox(width: _width, height: _height);
+    if (color != null) {
+      _w = ColoredBox(color: color!, child: _w);
+    }
+    return _w;
+  }
+}
+
+class SliverGap extends StatelessWidget {
+  const SliverGap.h(
+    double width, {
+    Key? key,
+    double? height,
+    this.color,
+  })  : _width = width,
+        _height = height,
+        super(key: key);
+
+  const SliverGap.v(
+    double height, {
+    Key? key,
+    double? width,
+    this.color,
+  })  : _width = width,
+        _height = height,
+        super(key: key);
+
+  final double? _width;
+  final double? _height;
+  final Color? color;
+
+  @override
+  Widget build(BuildContext context) {
+    Widget child;
+    if (_width != null) {
+      child = Gap.h(_width!, height: _height, color: color);
+    } else if (_height != null) {
+      child = Gap.v(_height!, width: _width, color: color);
+    } else {
+      child = const SizedBox.shrink();
+    }
+    return SliverToBoxAdapter(child: child);
+  }
+}