importer: Show "Install protocol support" button when protocol support is missing
Currently, when the protocol support is not installed (e.g. kamera), the importer will report "Unknown protocol" error and leaves the dialog empty without any further instruction. The behavior is not friendly for 1-dot users as mentioned in the Nate's blog article.
This commit adds a button named "Install protocol support for %1". The
button is only visible when DocumentDirFinder emits
KIO::Error::ERR_CANNOT_CREATE_SLAVE error. The button can
- open Discover and directly open kamera page if the scheme is "camera".
- open Discover and search the scheme for other schemes.
To make DocumentDirFinder able to emit error signal, a new signal
named error() is added to DocumentDirFinder.
| Kamera is missing | Nav to Kamera page if the protocol is "camera" | Other protocol | Search for the protocol name |
|---|---|---|---|
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