CODEWITHSUNDEEP
androidcordova
Josh
Josh

Reputation: 441

Why does my phoneGap Android application crash on resume?

I recently began writing a phonegap android application and noticed that when the app is resumed from the background (so I deploy the app to an android tablet, press the home button and then reopen the app from the menu) it gives a timeout error (something to the effect of Error code =-6 The connection to the server was unsuccessful) and then crashes. From what I've tested this only seems to happen when the "Don't keep activities" option is checked in the developer options, when that option is not checked the app works as intended.

It's also worth noting that I recreated the default phonegap application, ran it and encountered the same issue.

Can anyone explain why this happens, or suggest a solution? Obviously I can get around this problem by simply leaving the Don't keep activities option unchecked, but I'm guessing the problem will persist on any android device that has this option checked, which just won't do.

I'm using phonegap 2.5.0 and testing on a device running Android 4.0.3,

Thanks, Josh

Upvotes: 0

Views: 1896

Answers (1)

FunkTheMonk
FunkTheMonk

Reputation: 10938

"Don't keep activities" is a developer tool to simulate user activity that would be extremely hard to test for. I personally believe all apps should be tested a second time (at least run automated tests) with this setting turned on, and devs should turn it on / off during development.

Your issue (which I've just ran into on v2.7) comes from a silly implementation of a timeout feature. CordovaWebView.loadUrlIntoView creates and locks (wait()) a thread for 20 seconds (default value), after which time it checks a value to see if the url finished loading - if it hasn't finished, it shows an error message.

This thread exists outside of the lifetime of your activity, so if the activity stops running, the Webview can never finish loading the url, and when the thread wakes up, it does Bad Things trying to show the error.

The same crash could happen without using "Don't keep activities" by simply having the user leave the application and then the system reclaiming the activity's resources (because it is low on memory or something) within 20 seconds.

Using a Handler seems like a more appropriate way to handle this timeout, but without changing the source there are a couple of hacky work arounds.

  1. Call System.exit(0) at the end of your Activity.onDestroy() - this is horrible, but if you only have the one activity and no services, it might be an option

  2. Use reflection to change CordovaWebView.loadUrlTimeout - this is horrible, but it should work, this is the value that the thread checks to see if the url loaded (inc by 1).

Upvotes: 1

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