# Updating Makie plot based on button action

**URL:** <https://discourse.julialang.org/t/updating-makie-plot-based-on-button-action/111706>\
**Category:** Visualization\
**Tags:** question, makie, animations\
**Created:** [March 16, 2024, 7:12pm UTC](https://discourse.julialang.org/t/updating-makie-plot-based-on-button-action/111706 "2024-03-16T19:12:30Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![jules](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jules](https://discourse.julialang.org/u/jules)\
**Post date:** [March 17, 2024, 6:11pm UTC](https://discourse.julialang.org/t/updating-makie-plot-based-on-button-action/111706/7 "2024-03-17T18:11:23Z")

</div>

You have a race condition because you set your `offflag` to true and immediately readjust the slider, but the async task only gets to the flag after setting the slider again itself. This logic here should be a bit more robust, async code is always more complicated to reason about than sync code:

```julia
function plot_random_with_button()
    f = Figure()
    ax = Axis(f[1, 1])
    
    buta = Button(f[2, :], label="Animate", tellwidth=false)
    buts = Button(f[3, :], label="Stop", tellwidth=false)
    sl = Slider(f[4, :], range=range(0, 2 * pi, 50))
    
    
    x = Observable(range(0, 2 * pi, 100))
    y = lift(x, sl.value) do x, p
        cos.(x .+ p)
    end
    p = plot!(x, y)

    
    taskref = Ref{Union{Nothing,Task}}(nothing)
    should_close = Ref(false)

    on(buta.clicks) do _
        if taskref[] === nothing
            taskref[] = @async begin
                for val in Iterators.cycle(sl.range[])
                    sleep(1 / 30)
                    set_close_to!(sl, val)
                    should_close[] && break
                end
                should_close[] = false
            end
        end
        Consume(true)
    end

    on(buts.clicks) do _
        if taskref[] !== nothing && !should_close[]
            should_close[] = true
            wait(taskref[])
            taskref[] = nothing
            set_close_to!(sl, 0)
        end
        Consume(true)
    end
    f
end

plot_random_with_button()

```

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