That is great news, thank you Zhiqiang! Just to be clear, I was only concerned data *may *be lost after update and just wanted to verify if generally localStorage is a reliable persistent storage even after version updates (and other scenarios). Actually, we try it update on a debug mode and fortunately data on localStorage was kept after an update.
There were similar questions I found on that on the web (Cordova related, not Crosswalk): http://stackoverflow.com/questions/20246353/localstorage-data-being-lost-after-phonegap-android-app-update http://stackoverflow.com/questions/8947933/localstorage-clearing-after-app-store-update http://stackoverflow.com/questions/9022339/iphone-localstorage-lifecycle-does-it-survive-an-app-update http://stackoverflow.com/questions/24175319/cordova-app-keep-localstorage-data-in-new-app-version Anyway, we attend do a check it further on alpha/beta channels of Google Play, and then if successful, also on the production channel. I'll let you know about the result of that. Thanks, - Roei. On Thu, Oct 30, 2014 at 7:22 AM, Zhang, Zhiqiang <[email protected]> wrote: > Hi Roei, > > > From: Crosswalk-help [mailto: > [email protected]] On Behalf Of Roei Tov > > Sent: Tuesday, October 28, 2014 07:16 > > > We have deployed our web application to Google Play store using Cordova > as the native wrapper and Crosswalk 8 for the web engine runtime (targeting > Android 4.0+ devices) . > > Glad to know this. If possible, I would like to try your app. > > > We are using localStorage API to store some specific(important) > information for the user of the device. Does the data that is stored in > the localStorage is kept after user updates to a newer version (we > don't care for the case of uninstall and then re-install)? > > I tried to create a test case to reproduce this issue, but unfortunately I > cannot reproduce it. > > - Firstly create a web page using localStorage at > http://zqzhang.github.io/experiment/localstorage/, which can display a > count of how many times the user has loaded the page. > - Then create an app with Crosswalk 8 on Android to access this web page > multiple times; which can check that localStorage API is able to use as a > persistent storage. And YES, the localStorage API is absolutely to be used > as a persistent storage per my testing. > - Then increase the app version (still with Crosswalk 8 embedded) and > upgrade the app on Android device (here using ‘adb install -r’ to simulate > app update from Google play); which is used to check if localStorage is > able to access the page’s local storage area. The answer is also YES. > - Rebuild the app with Crosswalk 9 on Android, and upgrade the app on > Android devices, to see if the data in local storage is lost or not. The > answer is YES; the data that is stored in the localStorage is still there. > > > If it is kept, do you know about any other scenarios that the data may > lost (e.g. upgrading to Crosswalk 9)? > > Per the simple testing above, upgrading to Crosswalk-9 won't make your app > lose the data. > > Per http://dev.w3.org/html5/webstorage/#disk-space, user agent should > limit the total amount of space allowed for storage areas. The data may > lost if it stores more the limited amount space. I don't know exactly the > amount of the limited space. But per https://arty.name/localstorage.html, > Crosswalk 8 gets "5200000 characters were stored successfully, but 5300000 > weren't." You can check whether this is enough for your app. > > Another scenario that the data may lost is that your app user > intentionally or un-intentionally clear the data :). I tried the test above > by intentionally clearing the data via system setting, the data is lost. > > > If data lost after update, what other alternative reliable storage that > endures after updates you recommend? > > No need this, I think. > > Thanks, > Zhiqiang > >
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