Ok, you probably googled this topic! But you will find solutions only for iOS or solutions only for Android. Perhaps a preinstalled thrid-party app must be installed.
Of course there are solutions for both platforms, but for free?
And how long does it take to integrate this in your app?
Perhaps you consider the FDK approach:
FScanbarcodes : ICanScanBarcodes;
procedure TFormMain.ScanClick(Sender: TObject);
FScanbarcodes := TAnyFactory.Factory.CreateObj<ICanScanBarcodes>;
FScanBarcodes.ScanResult(Procedure (AResult : String)
LBLScanResult.Text := AResult;
FScanbarcodes := NIL;
Internal I'm using the ZXING Source for Android. For iOS you can choose between the ZBar or the ZXING version. ZBar ist based on the TMSWrapper for ZBar!
The ZXING Version is inspired by MVP Andrea Magni, but without the FrameStand and other overhead.
Threading is done with my TAnyCommandProcessor, that can queue the workflow for the Bitmaps, that are captured with the TCameraComponent!