1、优化StateLayout控件(修改列表空省图展示逻辑)

lib/widget/state_layout.dart

@@ -34,7 +34,7 @@ class _StateLayoutState extends State<StateLayout> {
   }
 
   Widget _loadingWidget() {
-    return Column(
+    return const Column(
       crossAxisAlignment: CrossAxisAlignment.center,
       mainAxisAlignment: MainAxisAlignment.center,
       children: [
@@ -46,19 +46,19 @@ class _StateLayoutState extends State<StateLayout> {
   Widget _otherWidget() {
     switch (widget.type) {
       case StateType.network:
-        return _buildNormalView(widget.errorImg ?? '', '无网络连接');
+        return _buildNormalView(widget.errorImg, '无网络连接');
       case StateType.loading:
         return Container();
       case StateType.empty:
-        return _buildNormalView(widget.emptyImg ?? '', widget.hintText ?? '暂无数据');
+        return _buildNormalView(widget.emptyImg, widget.hintText ?? '暂无数据');
       case StateType.error:
-        return _buildNormalView(widget.errorImg ?? '', '加载失败，请点击重试');
+        return _buildNormalView(widget.errorImg, '加载失败，请点击重试');
       case StateType.success:
         return Container();
     }
   }
 
-  Widget _buildNormalView(String img, String hintText) {
+  Widget _buildNormalView(String? img, String hintText) {
     return GestureDetector(
       onTap: () {
         if (widget.onRefresh != null) {
@@ -70,11 +70,11 @@ class _StateLayoutState extends State<StateLayout> {
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
           const SizedBox(height: 30.0),
-          ImageWidget.loadAssetImage(
+          img != null && img.isNotEmpty ?ImageWidget.loadAssetImage(
             img,
             width: 133.5*2,
             height: 95*2,
-          ),
+          ): const SizedBox(),
           Text(
             hintText,
             style: const TextStyle(