[camera] Fix IllegalStateException being thrown in Android implementation when switching activities. #4319

BeMacized · 2021-09-07T13:54:31Z

This PR removes the lifecycle hooks from the Android implementation. I have a feeling these were added by accident during the recent refactor, as the example app already puts this responsibility on the user of the plugin.
This is also described in the readme: https://github.com/flutter/plugins/tree/master/packages/camera/camera#handling-lifecycle-states

This should fix the issue with the IllegalStateException being thrown when switching to a different activity, for example when using camera in combination with image_picker, as can be seen in the issue linked below:

Relevant issues:

Pre-launch Checklist

packages/camera/camera/CHANGELOG.md

AlexV525 · 2021-09-13T03:46:09Z

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

-      backgroundHandlerThread.start();
-    } catch (IllegalThreadStateException e) {
-      // Ignore exception in case the thread has already started.
+    if (backgroundHandlerThread == null) {


Could we add a lifecycle test to avoid re-involved with the same issue?

There is a unit-test which tests for the if statement. However I am not sure how we could add a test to verify that we don't add implementation of listening to lifecycle events in the future.

Do you have some insights on how this could be accomplished?

Add an observer WidgetsBindingObserver in a Flutter App, then override the didChangeAppLifecycleState might be a solution.

Capturing from a separate discussion, verifying that the core classes (Camera, CameraPlugin) are not instanceof LifecycleObserver seems like a possible approach, even if it's not foolproof (e.g., a composed object could implement it)

alternatively, it could just return earlier.

if (backgroundHandlerThread != null) { return; }

google-cla · 2021-09-23T09:39:47Z

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google-cla · 2021-09-23T10:11:50Z

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BeMacized · 2021-09-23T19:44:35Z

@googlebot I consent.

google-cla · 2021-09-23T19:44:46Z

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mvanbeusekom · 2021-09-23T19:45:35Z

@googlebot I consent.

stuartmorgan · 2021-09-23T20:14:35Z

@blasten @bparrishMines Could one of you review this? It fixes a P2 regression.

blasten · 2021-09-23T22:02:11Z

packages/camera/camera/CHANGELOG.md

@@ -1,3 +1,8 @@
+


no need for this line

blasten

lgtm

@blasten

According to feedback from @blasten on PR, the following changes are made: - Removed an obsolete empty line in the CHANGELOG.md; - Return early from the `startBackgroundThread` function when the `backgroundHandlerThread is not `null`. This simplifies the method making it easier to read and understand.

…plementation when switching activities. (flutter/plugins#4319)

…plementation when switching activities. (flutter/plugins#4319) (#90857)

* master: [google_maps_flutter] Add Marker drag events (flutter#2838) [flutter_plugin_tools] Validate pubspec description (flutter#4396) Add file_selector to the repo list (flutter#4395) [in_app_purchase] Fix in_app_purchase_android/README.md (flutter#4363) [google_maps_flutter_web] Add Marker drag events (flutter#4385) [webview_flutter] Fixed todos in FlutterWebView.java (flutter#4394) Handle `PurchaseStatus.restored` correctly in example. (flutter#4393) Handle restored purchases in iOS example app (flutter#4392) [file_selector] Remove custom analysis options (flutter#4382) [flutter_plugin_tools] Check licenses in Kotlin (flutter#4373) Fixed _CastError when running example App (flutter#4390) [in_app_purchase] Ensure the introductoryPriceMicros field is transported as a String. (flutter#4370) Load navigation controls immediately. (flutter#4377) [camera] Fix IllegalStateException being thrown in Android implementation when switching activities. (flutter#4319) # Conflicts: # packages/webview_flutter/webview_flutter/CHANGELOG.md # packages/webview_flutter/webview_flutter_android/CHANGELOG.md

…plementation when switching activities. (flutter/plugins#4319) (flutter#90857)

…tion when switching activities. (flutter#4319)

BeMacized requested a review from bparrishMines as a code owner September 7, 2021 13:54

google-cla bot added the cla: yes label Sep 7, 2021

github-actions bot added p: camera platform-android labels Sep 7, 2021

BeMacized mentioned this pull request Sep 7, 2021

[camera] App throws exception when opening gallery flutter/flutter#89352

Closed

BeMacized requested a review from mvanbeusekom September 7, 2021 14:00

AlexV525 mentioned this pull request Sep 13, 2021

[BUG] [Android] camera cannot shoot after app pause(open other app) fluttercandies/flutter_wechat_camera_picker#50

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AlexV525 reviewed Sep 13, 2021

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mvanbeusekom mentioned this pull request Sep 15, 2021

[camera][regression] App fatally crashes when quickly switching cameras only on Android flutter/flutter#89431

Closed

danagbemava-nc mentioned this pull request Sep 16, 2021

[camera] startImageStream - Lifecycle Issues flutter/flutter#90070

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google-cla bot added cla: no and removed cla: yes labels Sep 23, 2021

google-cla bot added cla: yes and removed cla: no labels Sep 23, 2021

stuartmorgan requested a review from blasten September 23, 2021 20:14

blasten reviewed Sep 23, 2021

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packages/camera/camera/CHANGELOG.md Outdated

@@ -1,3 +1,8 @@

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no need for this line

blasten approved these changes Sep 23, 2021

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mvanbeusekom force-pushed the issue/89352 branch from 1a4add1 to 13976d3 Compare September 27, 2021 09:56

BeMacized and others added 6 commits September 27, 2021 23:36

[camera] Fixed IllegalStateException being thrown on activity switch.

ab492d2

Fix test

6dd242a

Added test

6361b4d

Update tests

6361c6e

Added tests to assert when LifecycleObserver is implemented.

467661e

mvanbeusekom force-pushed the issue/89352 branch from 13976d3 to 9561993 Compare September 27, 2021 21:37

mvanbeusekom added the waiting for tree to go green (Use "autosubmit") This PR is approved and tested, but waiting for the tree to be green to land. label Sep 28, 2021

fluttergithubbot merged commit 8a71e0e into flutter:master Sep 28, 2021

engine-flutter-autoroll mentioned this pull request Sep 28, 2021

Roll Plugins from f58ab59880d7 to 8a71e0ee47c7 (1 revision) flutter/flutter#90857

Merged

engine-flutter-autoroll added a commit to engine-flutter-autoroll/flutter that referenced this pull request Sep 28, 2021

8a71e0e [camera] Fix IllegalStateException being thrown in Android im…

b8ce5fc

…plementation when switching activities. (flutter/plugins#4319)

mvanbeusekom deleted the issue/89352 branch September 28, 2021 07:19

fluttergithubbot pushed a commit to flutter/flutter that referenced this pull request Sep 28, 2021

8a71e0e [camera] Fix IllegalStateException being thrown in Android im…

7674352

…plementation when switching activities. (flutter/plugins#4319) (#90857)

clocksmith pushed a commit to clocksmith/flutter that referenced this pull request Oct 29, 2021

8a71e0e [camera] Fix IllegalStateException being thrown in Android im…

14e184c

…plementation when switching activities. (flutter/plugins#4319) (flutter#90857)

sagargpt pushed a commit to nurture-farm/plugins that referenced this pull request Dec 6, 2021

[camera] Fix IllegalStateException being thrown in Android implementa…

6a61704

…tion when switching activities. (flutter#4319)

amantoux pushed a commit to amantoux/plugins that referenced this pull request Dec 11, 2021

[camera] Fix IllegalStateException being thrown in Android implementa…

a30f0fb

…tion when switching activities. (flutter#4319)

KyleFin pushed a commit to KyleFin/plugins that referenced this pull request Dec 21, 2021

[camera] Fix IllegalStateException being thrown in Android implementa…

34f6564

…tion when switching activities. (flutter#4319)

darshankawar mentioned this pull request Jan 5, 2022

[camera] MessageQueue: java.lang.IllegalStateException: Handler sending message to a Handler on a dead thread flutter/flutter#96140

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[camera] Fix IllegalStateException being thrown in Android implementation when switching activities. #4319

[camera] Fix IllegalStateException being thrown in Android implementation when switching activities. #4319

BeMacized commented Sep 7, 2021 •

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AlexV525 Sep 13, 2021

mvanbeusekom Sep 15, 2021

AlexV525 Sep 15, 2021

stuartmorgan Sep 22, 2021

blasten Sep 23, 2021

blasten Sep 23, 2021

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BeMacized commented Sep 23, 2021

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[camera] Fix IllegalStateException being thrown in Android implementation when switching activities. #4319

[camera] Fix IllegalStateException being thrown in Android implementation when switching activities. #4319

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BeMacized commented Sep 7, 2021 • edited Loading

Pre-launch Checklist

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