Scanning QR Code and update column without adding new row

[Kasidit]

I'm creating an app that let user scan QR Code on the item and The app will mark "✔" on the 'Marked' Column in the same row, I'm struggling with the qr code scanning method.

My expectation is when the user click the QR Scanning icon(I want this icon to show in Bottom right corner where Add action usually located but i can't find a way yet),then user scan the QR Code and the app will mark "✔"  in 'Marked' column in database.Now when the user click the QR Code icon there's nothing happen,I tried adding a form views,The scanning is work but i cannot save the scanned value because it's adding the new row into the table,making 'there's already a row with a key'xxx' shown up.


This is the action which i've created 

I also set the 'Scanned QR' to scannable already

[Steve]

Your Open QR Scanner action doesn't open the QR scanner. Instead, you need an action of type App: go to another view in this app with a target that uses LINKTOROW() to target a suitable form view of that [_THISROW]. That form view should include only the Scanned QR column and have auto-advance and auto-save enabled.