01 - Getting started

This page gets a small FlowUI window running in a few minutes.

Requirements

• Go 1.26.2 or newer
• A desktop platform supported by Gio: Windows, macOS, or Linux

Install

Inside your Go module:

go get github.com/qianniancn/flowui/ui

Applications should import the public facade only:

import "github.com/qianniancn/flowui/ui"

Do not import github.com/qianniancn/flowui/internal/....

First application

Create main.go:

package main

import (
    "fmt"

    "github.com/qianniancn/flowui/ui"
)

type Model struct {
    Count int
}

type Msg interface{ msg() }

type Inc struct{}
type Dec struct{}

func (Inc) msg() {}
func (Dec) msg() {}

func Update(m *Model, msg Msg) ui.Cmd[Msg] {
    switch msg.(type) {
    case Inc:
        m.Count++
    case Dec:
        m.Count--
    }
    return nil
}

func View(_ *ui.Context, m Model, send ui.Send[Msg]) ui.Widget {
    return ui.Center(
        ui.Column(
            ui.Text("FlowUI Counter").Size(24),
            ui.Text(fmt.Sprintf("Count: %d", m.Count)),
            ui.Row(
                ui.Button("decrement", ui.Text("-1")).OnClick(func() {
                    send(Dec{})
                }),
                ui.Button("increment", ui.Text("+1")).OnClick(func() {
                    send(Inc{})
                }),
            ).Gap(8),
        ).Gap(12),
    )
}

func main() {
    ui.Run(ui.NewProgram(Model{}, Update, View),
        ui.Title("FlowUI Counter"),
        ui.Size(640, 480),
    )
}

Run it with:

go run .

The same program is available in examples/counter.

What happened?

1. Model owns the application state.
2. Msg describes user intent.
3. Update is the only place that changes the model.
4. View reads the model and returns a widget tree.
5. ui.Run creates the window and starts the MVU loop.

Choose an application level

API	Use it for
ui.Run(ui.Program)	A single window
ui.Application	Multiple windows, tray integration, or explicit lifecycle control

Continue with Core concepts, or read the MVU and messages guide.