🐛 Allows wrapControllerMethod to return nullable result (#241)

Fixes #240

Author: AlexV525

CHANGELOG.md

@@ -6,6 +6,16 @@ that can be found in the LICENSE file. -->
 
 See the [Migration Guide](guides/migration_guide.md) for breaking changes between versions.
 
+## 4.2.2
+
+### Fixes
+
+- Allows `wrapControllerMethod` to return nullable result
+
+### Improvements
+
+- Provide the back button when no controller has been initialized.
+
 ## 4.2.1
 
 ### Fixes

example/pubspec.yaml

@@ -1,6 +1,6 @@
 name: wechat_camera_picker_demo
 description: A new Flutter project.
-version: 4.2.1+33
+version: 4.2.2+34
 publish_to: none
 
 environment:

lib/src/states/camera_picker_state.dart

@@ -304,7 +304,7 @@ class CameraPickerState extends State<CameraPicker>
   ///
   /// 对于 [CameraController] 的方法增加是否无效的控制。
   /// 如果 [T] 是非 void 且方法无效，返回 [fallback]。
-  Future<T> wrapControllerMethod<T>(
+  Future<T?> wrapControllerMethod<T>(
     String key,
     Future<T> Function() method, {
     CameraDescription? description,
@@ -313,7 +313,7 @@ class CameraPickerState extends State<CameraPicker>
   }) async {
     description ??= currentCamera;
     if (invalidControllerMethods[description]!.contains(key)) {
-      return fallback!;
+      return fallback;
     }
     try {
       return await method();
@@ -431,37 +431,37 @@ class CameraPickerState extends State<CameraPicker>
               () => newController.getExposureOffsetStepSize(),
               description: description,
               fallback: exposureStep,
-            ).then((value) => exposureStep = value),
+            ).then((value) => exposureStep = value!),
             wrapControllerMethod(
               'getMaxExposureOffset',
               () => newController.getMaxExposureOffset(),
               description: description,
               fallback: maxAvailableExposureOffset,
-            ).then((value) => maxAvailableExposureOffset = value),
+            ).then((value) => maxAvailableExposureOffset = value!),
             wrapControllerMethod(
               'getMinExposureOffset',
               () => newController.getMinExposureOffset(),
               description: description,
               fallback: minAvailableExposureOffset,
-            ).then((value) => minAvailableExposureOffset = value),
+            ).then((value) => minAvailableExposureOffset = value!),
             wrapControllerMethod(
               'getMaxZoomLevel',
               () => newController.getMaxZoomLevel(),
               description: description,
               fallback: maxAvailableZoom,
-            ).then((value) => maxAvailableZoom = value),
+            ).then((value) => maxAvailableZoom = value!),
             wrapControllerMethod(
               'getMinZoomLevel',
               () => newController.getMinZoomLevel(),
               description: description,
               fallback: minAvailableZoom,
-            ).then((value) => minAvailableZoom = value),
+            ).then((value) => minAvailableZoom = value!),
             wrapControllerMethod(
               'getMinZoomLevel',
               () => newController.getMinZoomLevel(),
               description: description,
               fallback: minAvailableZoom,
-            ).then((value) => minAvailableZoom = value),
+            ).then((value) => minAvailableZoom = value!),
             if (pickerConfig.lockCaptureOrientation != null)
               wrapControllerMethod<void>(
                 'lockCaptureOrientation',
@@ -1172,6 +1172,13 @@ class CameraPickerState extends State<CameraPicker>
   /// This displayed at the top of the screen.
   /// 该区域显示在屏幕上方。
   Widget buildSettingActions(BuildContext context) {
+    if (innerController == null) {
+      return Container(
+        alignment: AlignmentDirectional.topStart,
+        padding: const EdgeInsets.symmetric(horizontal: 12),
+        child: buildBackButton(context),
+      );
+    }
     return buildInitializeWrapper(
       builder: (CameraValue v, __) {
         if (v.isRecordingVideo) {
@@ -1787,7 +1794,6 @@ class CameraPickerState extends State<CameraPicker>
           children: <Widget>[
             Semantics(
               sortKey: const OrdinalSortKey(0),
-              hidden: innerController == null,
               child: buildSettingActions(context),
             ),
             const Spacer(),

pubspec.yaml

@@ -1,5 +1,5 @@
 name: wechat_camera_picker
-version: 4.2.1
+version: 4.2.2
 description: |
   A camera picker for Flutter projects based on WeChat's UI,
   which is also a separate runnable extension to the