✨Add custom onPicked callback when asset entity is generated (#268)

### Context
Currently, when a picture or video is taken using the camera, the
AssetEntity is retrieved via:
```
final assetEntity = await pickFromCamera(context);
```
This is achieved by calling `Navigator.of(context).pop(entity);`, which
returns the `AssetEntity` to the previous screen.

However, this approach has a limitation when the `CameraPicker` widget
is used in a scenario where it doesn't trigger a pop event, such as when
the widget is part of a tab or a persistent page in a navigation stack.
In these cases, there is no straightforward way to retrieve the captured
`AssetEntity`.

### Changes
- Introduced a custom `onPicked` callback that directly provides the
generated AssetEntity without relying on the
`Navigator.of(context).pop(entity);`.

---------

Co-authored-by: yujune <yujune@feedme.cc>
Co-authored-by: Alex Li <github@alexv525.com>

README-ZH.md

@@ -206,6 +206,7 @@ final AssetEntity? entity = await CameraPicker.pickFromCamera(
 | onError                       | `CameraErrorHandler?`       | 拍摄照片过程中的自定义错误处理                                    | null                                       |
 | onXFileCaptured               | `XFileCapturedCallback?`    | 拍摄文件生成后的回调                                         | null                                       |
 | onMinimumRecordDurationNotMet | `VoidCallback?`             | 录制时长未达到最小时长时的回调方法                                  | null                                       |
+| onPickConfirmed                      | `void Function(AssetEntity)?`    | 拍照或录像确认时的回调方法。                                       | null                                       |
 
 ### 使用自定义的 `State`
 

README.md

@@ -211,6 +211,7 @@ Fields in `CameraPickerConfig`:
 | onError                       | `CameraErrorHandler?`       | The error handler when any error occurred during the picking process.                                 | null                                       |
 | onXFileCaptured               | `XFileCapturedCallback?`    | The callback type definition when the XFile is captured by the camera.                                | null                                       |
 | onMinimumRecordDurationNotMet | `VoidCallback?`             | The callback when the recording is not met the minimum recording duration.                            | null                                       |
+| onPickConfirmed                      | `void Function(AssetEntity)?`    | The callback when picture is taken or video is confirmed.                                             | null                                       |
 
 ### Using custom `State`s
 

lib/src/constants/config.dart

@@ -5,6 +5,7 @@
 import 'package:camera/camera.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:photo_manager/photo_manager.dart';
 
 import '../delegates/camera_picker_text_delegate.dart';
 import 'type_defs.dart';
@@ -42,6 +43,7 @@ final class CameraPickerConfig {
     this.onError,
     this.onXFileCaptured,
     this.onMinimumRecordDurationNotMet,
+    this.onPickConfirmed,
   }) : assert(
           enableRecording == true || onlyEnableRecording != true,
           'Recording mode error.',
@@ -165,4 +167,8 @@ final class CameraPickerConfig {
   /// The callback when the recording is not met the minimum recording duration.
   /// 录制时长未达到最小时长时的回调方法。
   final VoidCallback? onMinimumRecordDurationNotMet;
+
+  /// The callback when the picture or the video is confirmed as picked.
+  /// 拍照或录像确认时的回调方法。
+  final void Function(AssetEntity)? onPickConfirmed;
 }

lib/src/states/camera_picker_state.dart

@@ -18,10 +18,10 @@ import 'package:sensors_plus/sensors_plus.dart';
 import 'package:wechat_picker_library/wechat_picker_library.dart';
 
 import '../constants/config.dart';
-import '../internals/singleton.dart';
 import '../constants/enums.dart';
 import '../delegates/camera_picker_text_delegate.dart';
 import '../internals/methods.dart';
+import '../internals/singleton.dart';
 import '../widgets/camera_focus_point.dart';
 import '../widgets/camera_picker.dart';
 import '../widgets/camera_picker_viewer.dart';
@@ -936,8 +936,11 @@ class CameraPickerState extends State<CameraPicker>
         viewType: CameraPickerViewType.image,
       );
       if (entity != null) {
-        Navigator.of(context).pop(entity);
-        return;
+        if (pickerConfig.onPickConfirmed case final onPickConfirmed?) {
+          onPickConfirmed(entity);
+        } else {
+          return Navigator.of(context).pop(entity);
+        }
       }
       wrapControllerMethod<void>(
         'setFocusMode',
@@ -1066,7 +1069,12 @@ class CameraPickerState extends State<CameraPicker>
         viewType: CameraPickerViewType.video,
       );
       if (entity != null) {
-        Navigator.of(context).pop(entity);
+        if (pickerConfig.onPickConfirmed case final onPickConfirmed?) {
+          await controller.resumePreview();
+          onPickConfirmed(entity);
+        } else {
+          Navigator.of(context).pop(entity);
+        }
       } else {
         await controller.resumePreview();
       }