refactor(empty-state): 空状态支持内容居中

lib/core/widgets/empty_state.dart

@@ -5,12 +5,12 @@ import 'package:flutter/material.dart';
 import '../theme/app_colors.dart';
 import '../theme/app_dimens.dart';
 
-const double _regularIconSize = 72;
-const double _compactIconSize = 44;
+const double _iconSize = 72;
 const double _maxContentWidth = 260;
 const double _regularHorizontal = 24;
 const double _regularVertical = 28;
-const double _compactPad = 16;
+const double _compactHorizontal = 16;
+const double _compactVertical = 4;
 const double _regularGap = 20;
 const double _compactGap = 12;
 const double _actionMinHeight = 44;
@@ -27,6 +27,7 @@ class EmptyState extends StatelessWidget {
     this.onAction,
     this.footer,
     this.compact = false,
+    this.stretchContent = false,
   });
 
   final IconData icon;
@@ -38,6 +39,9 @@ class EmptyState extends StatelessWidget {
   final Widget? footer;
   final bool compact;
 
+  /// 让图标和文案占满内容宽度，适用于需要严格居中的宽版空状态。
+  final bool stretchContent;
+
   @override
   Widget build(BuildContext context) {
     final hasAction = actionLabel != null && onAction != null;
@@ -48,28 +52,33 @@ class EmptyState extends StatelessWidget {
         child: Padding(
           key: const Key('empty-state-padding'),
           padding: EdgeInsets.symmetric(
-            horizontal: compact ? _compactPad : _regularHorizontal,
-            vertical: compact ? _compactPad : _regularVertical,
+            horizontal: compact ? _compactHorizontal : _regularHorizontal,
+            vertical: compact ? _compactVertical : _regularVertical,
           ),
-          child: Semantics(
-            container: true,
-            label: title,
-            child: Column(
-              mainAxisSize: MainAxisSize.min,
-              children: [
-                ExcludeSemantics(
-                  child: _EmptyMark(icon: icon, compact: compact),
-                ),
-                SizedBox(height: compact ? _compactGap : _regularGap),
-                _EmptyCopy(
-                  title: title,
-                  subtitle: subtitle,
-                  actionLabel: hasAction ? actionLabel : null,
-                  actionKey: actionKey,
-                  onAction: hasAction ? onAction : null,
-                  footer: footer,
-                ),
-              ],
+          child: SizedBox(
+            width: stretchContent ? double.infinity : null,
+            child: Semantics(
+              container: true,
+              label: title,
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  ExcludeSemantics(child: _EmptyMark(icon: icon)),
+                  SizedBox(height: compact ? _compactGap : _regularGap),
+                  SizedBox(
+                    width: stretchContent ? double.infinity : null,
+                    child: _EmptyCopy(
+                      title: title,
+                      subtitle: subtitle,
+                      actionLabel: hasAction ? actionLabel : null,
+                      actionKey: actionKey,
+                      onAction: hasAction ? onAction : null,
+                      footer: footer,
+                      stretchContent: stretchContent,
+                    ),
+                  ),
+                ],
+              ),
             ),
           ),
         ),
@@ -80,17 +89,16 @@ class EmptyState extends StatelessWidget {
 
 /// 空列表只放一枚大图标，不画线框，也不铺底色。
 class _EmptyMark extends StatelessWidget {
-  const _EmptyMark({required this.icon, required this.compact});
+  const _EmptyMark({required this.icon});
 
   final IconData icon;
-  final bool compact;
 
   @override
   Widget build(BuildContext context) {
     return Icon(
       icon,
       key: const Key('empty-state-icon'),
-      size: compact ? _compactIconSize : _regularIconSize,
+      size: _iconSize,
       color: AppColors.subtle,
     );
   }
@@ -104,6 +112,7 @@ class _EmptyCopy extends StatelessWidget {
     required this.actionKey,
     required this.onAction,
     required this.footer,
+    required this.stretchContent,
   });
 
   final String title;
@@ -112,11 +121,15 @@ class _EmptyCopy extends StatelessWidget {
   final Key? actionKey;
   final VoidCallback? onAction;
   final Widget? footer;
+  final bool stretchContent;
 
   @override
   Widget build(BuildContext context) {
     return Column(
       mainAxisSize: MainAxisSize.min,
+      crossAxisAlignment: stretchContent
+          ? CrossAxisAlignment.stretch
+          : CrossAxisAlignment.center,
       children: [
         ExcludeSemantics(
           child: Text(