feature/#21 - scan now uses local database, for product look up and for its history

[monsieurtanuki]

New file:

• scan_page.dart: helper class to be used on top of AlternativeContinuousScanPage and ContinuousScanPage

Impacted files:

• alternative_continuous_scan_page.dart: ContinuousScanModel is now initialized upstream by ScanPage
• continuous_scan_model.dart: now a ChangeNotifier, uses a ProductList and database cache
• continuous_scan_page.dart: ContinuousScanModel is now initialized upstream by ScanPage
• contribution_page.dart: uses the new ScanPage widget instead of the 2 scan pages
• local_database.dart: removed the dummy notify listener method
• main.dart: uses the new ScanPage widget instead of the 2 scan pages
• personalized_ranking_page.dart: now we use a ProductList as input
• product_list.dart: added a getProduct method and a "scan list" identifier
• product_page.dart: unrelated UI fixes
• product_query_page.dart: slight refactoring
• smooth_it_model.dart: now we use ProductList
• smooth_product_carousel.dart: added the new "CACHED" product possibility; fixed an init bug

[M123-dev]

I'll take a closer look at it later, just one thing on the side. We are still using qr_code_scanner ^0.0.13 but the newest is 0.3.0. The only big change is minSdk 20 and that the scanner delivers an object and not a string. The string can be obtained again with object.code. I think it would be good if you change this, since you're on the subject right now.

[monsieurtanuki]

@M123-dev I don't know the general target for Android minSdk on this app, @stephanegigandet perhaps?

I'm a bit concerned for 2 reasons:

• I prefer the lowest possible API level in general
• my smartphone runs on API 21 - it's getting closer...

For the record:

• API 19: 98.1%
• API 20: 94.1%
• API 21: 94.1%
• API 22: 92.3%

Therefore I won't upgrade to qr_code_scanner ^0.3.0 in this PR, though I don't feel "furiously angry" with the concept of upgrading from API 19 to API 20.

[M123-dev]

The app currently has minSdk version 19 and yes, I agree with you, I would definitely keep the version as deep as possible. Unfortunately, I couldn't find any correct information in the changelogs why and when it was upgraded. Only in version 0.1.0 it was reduced from 24 to 21.
I have to say I am not satisfied with the scanners anyway, so I hoped that the update would fix this, has the choice already been made or is the final scanner still being searched?

[M123-dev]

Looks good

[monsieurtanuki]

Thank you @M123-dev!

@PrimaelQuemerais I've just merged anyway, but I think I found something interesting about the "local provider" / "async init" questions: please have a look at scan_page.dart and its build method.