hey is there any good reference for the compose api to draw kotlinlang #compose

hey, is there any good reference for the compose api to draw the shapes for custom UI elements (and make them user intractable)? So I was using canvas fo that purpose, and wanted to clarify if that’s the right approach?

Adam Powell

04/26/2020, 4:51 PM

it's a goal of compose to make it easy to do it that way, so sure, please report back 🙂

you might want to poke around in the

ui-foundation

layers as a lot of interaction constructs live there to be used in building components like that

Sheroz Nazhmudinov

04/26/2020, 6:04 PM

sounds good, i wanted to give it a try - drawing custom ui components and make them user intractable🙂

👍 1

I have a use case at the moment: I have a custom view and I want to make certain “part” of it draggable. So i was thinking if that’s the right approach:

@Composable

fun Custom(modifier: Modifier = Modifier) {

Canvas(modifier = modifier.plus(

Modifier.draggable(dragDirection = DragDirection.Horizontal) {

// drag callback

)) {

drawRoundRect(...)

drawCircle(...)

So in my case i wanna make circle draggable.

Adam Powell

04/26/2020, 8:43 PM

first off, just do

modifier.draggable(...)

modifier.plus(Modifier.draggable(...))

is entirely redundant 🙂

👍 1

Sheroz Nazhmudinov

04/27/2020, 11:39 AM

so to make it a bit simpler i decide to do smth else: I wrapped the

Canvas

with

Clickable

, and wanted to change the state of circle based on click. However, the click isn’t triggered. The only way I managed to trigger the

onClick

was setting the specific

width

and

height

Clickable

via the `modifier`… i guess i’d expect the

Clickable

to have already the size of the content of the

Canvas

. I hope it makes sense what I’m trying to say…

Ash

04/27/2020, 8:42 PM

Can we make certain part of the canvas clickable?

For example a rectangle inside the canvas?

Sheroz Nazhmudinov

04/28/2020, 7:29 PM

i get a compile error when i try to make some parts of custom drawing clickable.

Functions which invoke @Composable functions must be marked with the @Composable annotation