♿️ Improve semantics expressions

Author: AlexV525

lib/src/delegates/camera_picker_text_delegate.dart

@@ -22,7 +22,7 @@ class CameraPickerTextDelegate {
   /// Semantics fields.
   ///
   /// Fields below are only for semantics usage. For customizable these fields,
-  /// head over to [EnglishCameraPickerTextDelegate] for fields understanding.
+  /// head over to [EnglishCameraPickerTextDelegate] for better understanding.
   String get sActionManuallyFocusHint => '手动聚焦';
 
   String get sActionPreviewHint => '预览';
@@ -35,24 +35,22 @@ class CameraPickerTextDelegate {
 
   String get sActionStopRecordingHint => '停止录像';
 
-  String get sActionSwitchCameraTooltip => '切换摄像头';
-
-  String get sActionToggleFlashModeTooltip => '切换闪光模式';
-
   String sCameraLensDirectionLabel(CameraLensDirection value) {
-    final String _direction;
     switch (value) {
       case CameraLensDirection.front:
-        _direction = '前置';
-        break;
+        return '前置';
       case CameraLensDirection.back:
-        _direction = '后置';
-        break;
+        return '后置';
       case CameraLensDirection.external:
-        _direction = '外置';
-        break;
+        return '外置';
+    }
+  }
+
+  String? sCameraPreviewLabel(CameraLensDirection? value) {
+    if (value == null) {
+      return null;
     }
-    return '当前摄像头: $_direction';
+    return '${sCameraLensDirectionLabel(value)}画面预览';
   }
 
   String sFlashModeLabel(FlashMode mode) {
@@ -71,7 +69,11 @@ class CameraPickerTextDelegate {
         _modeString = '始终闪光';
         break;
     }
-    return '当前闪光模式: $_modeString';
+    return '闪光模式: $_modeString';
+  }
+
+  String sSwitchCameraLensDirectionLabel(CameraLensDirection value) {
+    return '切换至${sCameraLensDirectionLabel(value)}摄像头';
   }
 }
 
@@ -129,18 +131,22 @@ class EnglishCameraPickerTextDelegate extends CameraPickerTextDelegate {
   String get sActionStopRecordingHint => 'stop recording';
 
   @override
-  String get sActionSwitchCameraTooltip => 'switch camera';
+  String sCameraLensDirectionLabel(CameraLensDirection value) => value.name;
 
   @override
-  String get sActionToggleFlashModeTooltip => 'toggle flashlight';
+  String? sCameraPreviewLabel(CameraLensDirection? value) {
+    if (value == null) {
+      return null;
+    }
+    return '${sCameraLensDirectionLabel(value)} camera preview';
+  }
 
   @override
-  String sCameraLensDirectionLabel(CameraLensDirection value) =>
-      'Current camera lens direction: ${value.name}';
+  String sFlashModeLabel(FlashMode mode) => 'Flash mode: ${mode.name}';
 
   @override
-  String sFlashModeLabel(FlashMode mode) =>
-      'Current flashlight mode: ${mode.name}';
+  String sSwitchCameraLensDirectionLabel(CameraLensDirection value) =>
+      'Switch to the ${sCameraLensDirectionLabel(value)} camera';
 }
 
 /// Default text delegate including recording implements with English.

lib/src/widgets/camera_picker.dart

@@ -625,6 +625,15 @@ class CameraPickerState extends State<CameraPicker>
     initCameras(currentCamera);
   }
 
+  /// Obtain the next camera description for semantics.
+  CameraDescription get _nextCameraDescription {
+    final int nextIndex = currentCameraIndex + 1;
+    if (nextIndex == cameras.length) {
+      return cameras[0];
+    }
+    return cameras[nextIndex];
+  }
+
   /// The method to switch between flash modes.
   /// 切换闪光灯模式的方法
   Future<void> switchFlashesMode() async {
@@ -1002,8 +1011,7 @@ class CameraPickerState extends State<CameraPicker>
           padding: const EdgeInsets.symmetric(horizontal: 12.0),
           child: Row(
             children: <Widget>[
-              if (cameras.length > 1)
-                switchCamerasButton(controller.description.lensDirection),
+              if (cameras.length > 1) switchCamerasButton,
               const Spacer(),
               switchFlashesButton(v),
             ],
@@ -1015,10 +1023,11 @@ class CameraPickerState extends State<CameraPicker>
 
   /// The button to switch between cameras.
   /// 切换相机的按钮
-  Widget switchCamerasButton(CameraLensDirection value) {
+  Widget get switchCamerasButton {
     return IconButton(
-      tooltip: '${_textDelegate.sActionSwitchCameraTooltip}, '
-          '${_textDelegate.sCameraLensDirectionLabel(value)}',
+      tooltip: _textDelegate.sSwitchCameraLensDirectionLabel(
+        _nextCameraDescription.lensDirection,
+      ),
       onPressed: switchCameras,
       icon: Icon(
         Platform.isIOS
@@ -1045,13 +1054,10 @@ class CameraPickerState extends State<CameraPicker>
         icon = Icons.flash_on;
         break;
     }
-    return Semantics(
-      label: '${_textDelegate.sActionToggleFlashModeTooltip}, '
-          '${_textDelegate.sFlashModeLabel(value.flashMode)}',
-      child: IconButton(
-        onPressed: switchFlashesMode,
-        icon: Icon(icon, size: 24),
-      ),
+    return IconButton(
+      onPressed: switchFlashesMode,
+      tooltip: _textDelegate.sFlashModeLabel(value.flashMode),
+      icon: Icon(icon, size: 24),
     );
   }
 
@@ -1374,7 +1380,10 @@ class CameraPickerState extends State<CameraPicker>
 
     return Positioned.fill(
       child: Semantics(
-        label: _textDelegate.sActionManuallyFocusHint,
+        label: _textDelegate.sCameraPreviewLabel(
+          _controller?.description.lensDirection,
+        ),
+        image: true,
         onTap: () => _focus(
           TapUpDetails(
             kind: PointerDeviceKind.touch,