Is there a way to know if a key pressed (onKeyEvent) will output a character or not when pressed? i...

# compose

[Alex Styl]

Is there a way to know if a key pressed (onKeyEvent) will output a character or not when pressed?

ie 'A' will print A, but meta,esc, cmd keys don't output any characters

[Alex Styl]

Made it work with:

fun isCharacterKey(event: KeyEvent): Boolean {
    val char = event.key.toString().replace("Key: ", "")
    return char.length == 1 && event.key !in listOf(
        Key.MetaLeft, Key.MetaRight,
        Key.Escape, Key.Delete, Key.Backspace,
        Key.Tab, Key.AltLeft, Key.AltRight
    )
}

[Alex Styl]

PS: The above tells you whether a "key" will print a character, but it will not tell you which character will be printed (ie upper or lower case). I found that you can get the actual keyChar (instead of the replace trick i do above) by using the actual platform.

On desktop you get it by awtEventOrNull!!.keyChar . haven't checked for others

PS2: Desktop also has a KeyEvent.isTypedEvent which i think does exactly what i want, but need this on web too

[Alex Styl]

This seems to be working reliably on both desktop and web:

expect val KeyEvent.isTypedEvent: Boolean

expect val KeyEvent.typedChar: String

// Desktop
actual val KeyEvent.isTypedEvent: Boolean
    get() {
        return this.isTypedEvent
    }

actual val KeyEvent.typedChar: String
    get() = awtEventOrNull!!.keyChar.toString()

// Web
actual val KeyEvent.isTypedEvent: Boolean
    get() {
        return this.typedChar.length == 1
    }

actual val KeyEvent.typedChar: String
    get() {
        return domEventOrNull!!.key
    }

[Alex Styl]

PS3: awsEventOrNull.isTypedEvent will only return true if the character is combined with the appropriate key type (key down, etc). so the above won't work on Desktop unless you use it on a TextField.

Just a headsup for whoever reads this in the future

[Trejkaz]

I use a compose key so the notion of a key necessarily outputting a character is iffy on my setup too, sometimes it just contributes to the current sequence

[Trejkaz]

I'm guessing typedChar does the right thing in this situation although the actual number of chars typed isn't always 1 either

[Trejkaz]

e.g. [compose] [compose] [a] [l] [e] [p] [0] would type ℵ₀ which is probably two

[Trejkaz]

[compose] [t] [f] types (ﾉಥ益ಥ）ﾉ彡┻━┻ which is 11 or so

[Trejkaz]

so I guess at the very least the correct check would be typedChar.length > 0 ?