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https://issues.apache.org/jira/browse/CB-3900?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13839248#comment-13839248
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Andrew Grieve commented on CB-3900:
-----------------------------------
Solution proposed in doc:
https://docs.google.com/document/d/1b2igeRoGXpdr_B89W7n2CaiXTspXq9tnrK5ocsyhNNM/edit#heading=h.bykm1gwhlrq0
> A blocked UI thread can result in 100s of accelerator messages banking up
> -------------------------------------------------------------------------
>
> Key: CB-3900
> URL: https://issues.apache.org/jira/browse/CB-3900
> Project: Apache Cordova
> Issue Type: Improvement
> Components: Android
> Affects Versions: 2.7.0
> Reporter: Peter
> Assignee: Joe Bowser
> Priority: Minor
>
> The OnlineEventsBridgeMode mechanism in NativeToJsMessageQueue uses
> *runOnUIThread* to tell some Runnable to fire and even which initiates
> processing of the queued messages.
> However, if the UI thread is blocked (eg user code is just sitting on an
> “alert”) then that Runnable will not have any chance to execute.
> Combining this case with an Accelerometer sensor (eg
> *getCurrentAcceleration*) and there is a possible scenario where
> * User sits on the alert, thereby blocking the UI thread for some length of
> time
> * The bridge message queue grows to 10s or 100s or 1000s of messages because
> the acceleration messages continue to be enqueued
> * 10s or 100s or even 1000s of UI runOnUIThread Runnables get queued up
> because the UI thread is blocked
> When the alert is finally dismissed, those (100s of?) Runnables all get a
> chance to run.
> While it all seems OK from the end user point-of-view, there appears to be an
> awful lot of (unnecessary?) work going on behind the scenes in this scenario.
> Example user code:
> {code} navigator.accelerometer.getCurrentAcceleration(onAccelerationSuccess,
> onAccelerationError);
> alert('Wait here and use debugger to watch the message queue growing');
> {code}
> I don’t know if there is any viable fix for this quirk, but even if there
> isn’t this potential ought to be described in a comment somewhere.
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