Handle special keys (soft keys, volume, camera) on KaiOS
Why it matters. A great user experience on KaiOS starts with directional navigation and proper keyboard handling.
Dive deeper. Not all devices support the same hard keys, and while most have a T9 layout, some like the JioPhone 2 have full QWERTY keyboards.
Special Keys
| Key | Key Code | Code | Description |
|---|---|---|---|
| SoftLeft | 0 | F13 | Left Soft Key (LSK), typically performs action |
| SoftRight | 0 | F15 | Right Soft Key (RSK), typically opens options menu |
| MicrophoneToggle | 0 | N/A | Launch the Voice Assistant (VA) via voice-assistant
Web Activity |
| Enter | 13 | Home | Select the currently-focused element |
| Backspace | 8 | KeyB | Go to previous page |
| GoBack | 0 | N/A | Go to previous back (KaiOS Smart Touch only) |
| BrowserBack | 0 | N/A | Go to previous page (web browser only) |
| VolumeUp | 182 | AudioVolumeUp | Raise volume |
| VolumeDown | 183 | AudioVolumeDown | Lower volume |
| Call | 0 | N/A | Launch the call screen or accept current action |
| EndCall | 95 | Power | Cancel the current action or close app |
| Power | 95 | Power | Toggle screen on/ off; long-press to power down |
| Camera | 0 | N/A | Open Camera app |
| HeadsetHook | 0 | N/A | Open Music app |
| LaunchWebBrowser | 0 | F14 | Launch Browser app |
| LaunchMail | 0 | N/A | Launch Email app |
| Message | 0 | KeyA | Launch SMS app |
| Notification | 0 | N/A | Open Notification panel |
| Symbol | 224 | F17 | Toggle symbol input (i.e. #, *, -, +, @, etc) |
Always use the
KeyboardEvent#key property, as many keys lack a keyCode, and the code property changes based on keyboard layout and device configuration. Keep in mind that many keys are limited to certain devices, although every KaiOS device has d-pad navigation as well as LSK and RSK.
Pro Tip: use Feature Detection to check if the device has hardware camera or volume buttons.
Using Special Keys
Here are a few ideas for how to use special keys:
Volume
- For an eReader app, scroll the page up or down
- For an image gallery, zoom in or out
- For a calendar app, toggle day/ week/ month view
Soft Keys
- For a game, perform an action like
AorBbuttons - For an image gallery, pan the image right or left
- For an app, open options or launch search page
Warning: Never block the user from leaving your app. Although KaiOS allows apps to intercept important navigational keys like Backspace and Power, users can typically long-press these keys to terminate your app.
Voice Assistant
There is one setting, voice-assistant.enabled, and two device preferences, dom.microphonetoggle.supported and dom.microphonetoggle.hardwareKey, that control the Voice Assistant (VA). Typically long-pressing Enter will trigger the MicrophoneToggle event, launching the voice-assistant activity that includes a single data element, from, that is either Homescreen, System, or the name of the app or website that the user was on before triggering the VA.
Conclusion
It’s easy to overlook special keys, but directional navigation and soft keys are important at delivering a top-notch user experience on KaiOS. If you need support adapting your website or PWA for easy navigation on KaiOS, contact the author from the About page.