Inside a composable I can copy text to the clipboa...

# compose

[Rick Regan]

Inside a composable I can copy text to the clipboard by doing something like LocalClipboardManager.current.setText(AnnotatedString("Copied to clipboard")). But how can I copy to the clipboard from a callback? I want to copy the state of a Text when a "copy all" icon button is pressed. (The composable SelectionContainer is not suitable for my app for several reasons.)

[Lukasz Burcon]

what about passing a mutableState containing the most up-to-date text?

[Rick Regan]

Do you mean have a composable function that generates no UI but takes that mutable state and calls LocalClipboardManager as above? That is an interesting solution except that I worry that "extra" recompositions (we have no control over them) could overwrite the clipboard when it's not supposed to. (Actually, now that I think about it, isn't writing to the clipboard a side effect, and thus to be avoided within a composable in any case?)

[Lukasz Burcon]

Side effects are nothing bad in Compose when used correctly. What I’d do is having a parent Composable, let’s say a Row in which a mutableState is defined and remembered. Then that mutableState would be passed as a parameter both to a TextField and IconButton (or anything you’d like to use). In the TextField you’d have to update the state whenever the text changes, and in the IconButton you’d just have to implement an onClick like this

val localClipboardManager = LocalClipboardManager.current
IconButton(
   icon = xxx,
   onClick = {
      localClipboardManager.setText(AnnotatedString("Copied to clipboard"))
   }
}

Look how I got the LocalClipboardManager instance outside of the onClick callback so I can use it in a non-Composable function 🙂

[Rick Regan]

That's a pretty neat trick (localClipboardManager), and side steps the side effect issue. Thanks! My onClick() calls a hoisted function to do the callback processing, so what I did was declare localClipboardManager in the higher level state object that the callback accesses, and initialize it in a high level composable.