[camera] Fixed stale images in imageStream subscriptions (flutter#3344)

* Fixed stale images in imageStream subscriptions

* Implemented feedback

* Fixed format exception

* added null-check for imageStreamReader

* Removed setOnImageAvailableListener from onCancel

* fixed formatting

Author: danielroek

packages/camera/camera/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.6.4+2
+
+* Set ImageStreamReader listener to null to prevent stale images when streaming images. 
+
 ## 0.6.4+1
 
 * Added closeCaptureSession() to stopVideoRecording in Camera.java to fix an Android 6 crash

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

@@ -943,6 +943,13 @@ public void setZoomLevel(@NonNull final Result result, float zoom) throws Camera
     result.success(null);
   }
 
+  public void stopImageStream() throws CameraAccessException {
+    if (imageStreamReader != null) {
+      imageStreamReader.setOnImageAvailableListener(null, null);
+    }
+    startPreview();
+  }
+
   private void closeCaptureSession() {
     if (cameraCaptureSession != null) {
       cameraCaptureSession.close();

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

@@ -219,7 +219,7 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull final Result result)
       case "stopImageStream":
         {
           try {
-            camera.startPreview();
+            camera.stopImageStream();
             result.success(null);
           } catch (Exception e) {
             handleException(e, result);

packages/camera/camera/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera
 description: A Flutter plugin for getting information about and controlling the
   camera on Android and iOS. Supports previewing the camera feed, capturing images, capturing video,
   and streaming image buffers to dart.
-version: 0.6.4+1
+version: 0.6.4+2
 homepage: https://github.com/flutter/plugins/tree/master/packages/camera/camera
 
 dependencies: