Ensure setExposureOffset returns new value on Android (#4301)

Author: mvanbeusekom

packages/camera/camera/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.2+2
+
+* Ensure that setting the exposure offset returns the new offset value on Android.
+
 ## 0.9.2+1
 
 * Fixed camera controller throwing an exception when being replaced in the preview widget.

packages/camera/camera/android/src/main/java/io/flutter/plugins/camera/Camera.java

@@ -906,7 +906,7 @@ public void setExposureOffset(@NonNull final Result result, double offset) {
     exposureOffsetFeature.updateBuilder(previewRequestBuilder);
 
     refreshPreviewCaptureSession(
-        () -> result.success(null),
+        () -> result.success(exposureOffsetFeature.getValue()),
         (code, message) ->
             result.error("setExposureOffsetFailed", "Could not set exposure offset.", null));
   }

packages/camera/camera/android/src/test/java/io/flutter/plugins/camera/CameraTest.java

@@ -687,11 +687,13 @@ public void setExposureOffset_shouldUpdateExposureOffsetFeature() {
         mockCameraFeatureFactory.createExposureOffsetFeature(mockCameraProperties);
     MethodChannel.Result mockResult = mock(MethodChannel.Result.class);
 
+    when(mockExposureOffsetFeature.getValue()).thenReturn(1.0);
+
     camera.setExposureOffset(mockResult, 1.0);
 
     verify(mockExposureOffsetFeature, times(1)).setValue(1.0);
     verify(mockResult, never()).error(any(), any(), any());
-    verify(mockResult, times(1)).success(null);
+    verify(mockResult, times(1)).success(1.0);
   }
 
   @Test

packages/camera/camera/example/lib/main.dart

@@ -399,6 +399,13 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                             onSetExposureModeButtonPressed(ExposureMode.locked)
                         : null,
                   ),
+                  TextButton(
+                    child: Text('RESET OFFSET'),
+                    style: styleLocked,
+                    onPressed: controller != null
+                        ? () => controller!.setExposureOffset(0.0)
+                        : null,
+                  ),
                 ],
               ),
               Center(

packages/camera/camera/pubspec.yaml

@@ -4,7 +4,7 @@ description: A Flutter plugin for getting information about and controlling the
   and streaming image buffers to dart.
 repository: https://github.com/flutter/plugins/tree/master/packages/camera/camera
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.2+1
+version: 0.9.2+2
 
 environment:
   sdk: ">=2.12.0 <3.0.0"