Let’s get straight down to business because I’m tired of hating on Bixby. But let me add in some context. You cannot remap the Bixby button to use it for any other app. However, there is a workaround that lets you remap it. You need an app called bxAxctions. Here’s how to remap the Bixby button on Galaxy S9.
Remap Bixby button on Galaxy S9
So before you begin, make sure you have enabled Bixby. This app won’t work if you have it disabled. And since bxActions will be running in the background all the time, battery life may be of concern. This is because the app needs to track the usage of the Bixby button. Another concern could be that Samsung may push a firmware update that may make bxActions completely useless.
So first, you need to install bxActions from the Google Play Store. It is completely free to use. Open the app and grant all the permissions it asks. This is necessary for the app to work correctly. Enable both the toggles. Enabling the Get foreground app will take you to the Usage Data Access screen. Tap on bxActions and enable Allow usage tracking. Now go back to the main screen and enable Get button events. This will take you to the Accessibility screen where you need to select bxActions and enable it. when a pop up appears, tap on OK. Head back to the bxActions app and tap on Done.
Also read: How to Disable Bixby in Galaxy Note 9
bxAxtions also has the option to differentiate between the long press and short press after you grant it more permissions using ADB. Tap on the Please unlock permissions using a PC to get instructions. But this is not that important and the app will run perfectly fine and as intended without granting permissions via ADB. We suggest you not to try it if you do not know how to use ADB or know what it is.