About Walk

Walk is a "Windows Application Library Kit" for the Go Programming Language.

Its primarily useful for Desktop GUI development, but there is some more stuff.

Setup

Make sure you have a working Go installation. See Getting Started

Note

Go 1.7.x doesn't work with walk anymore, Make sure you use Go 1.8.x or later.

To Install

Now run go get github.com/lxn/walk

Using Walk

The preferred way to create GUIs with Walk is to use its declarative sub package, as illustrated in this small example:

test.go

package main

import (
	"github.com/lxn/walk"
	. "github.com/lxn/walk/declarative"
	"strings"
)

func main() {
	var inTE, outTE *walk.TextEdit

	MainWindow{
		Title:   "SCREAMO",
		MinSize: Size{600, 400},
		Layout:  VBox{},
		Children: []Widget{
			HSplitter{
				Children: []Widget{
					TextEdit{AssignTo: &inTE},
					TextEdit{AssignTo: &outTE, ReadOnly: true},
				},
			},
			PushButton{
				Text: "SCREAM",
				OnClicked: func() {
					outTE.SetText(strings.ToUpper(inTE.Text()))
				},
			},
		},
	}.Run()
}

Create Manifest test.manifest

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity version="1.0.0.0" processorArchitecture="*" name="SomeFunkyNameHere" type="win32"/>
    <dependency>
        <dependentAssembly>
            <assemblyIdentity type="win32" name="Microsoft.Windows.Common-Controls" version="6.0.0.0" processorArchitecture="*" publicKeyToken="6595b64144ccf1df" language="*"/>
        </dependentAssembly>
    </dependency>
    <application xmlns="urn:schemas-microsoft-com:asm.v3">
        <windowsSettings>
            <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2, PerMonitor</dpiAwareness>
            <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">True</dpiAware>
        </windowsSettings>
    </application>
</assembly>

Then either compile the manifest using the rsrc tool, like this:

go get github.com/akavel/rsrc
rsrc -manifest test.manifest -o rsrc.syso

or rename the test.manifest file to test.exe.manifest and distribute it with the application instead.

Build app

In the directory containing test.go run

go build

To get rid of the cmd window, instead run

go build -ldflags="-H windowsgui"

Run app

test.exe

Sample Output (Windows 7)

More Examples

There are some examples that should get you started.

Application Manifest Files

Walk requires Common Controls 6. This means that you must put an appropriate application manifest file either next to your executable or embedded as a resource.

You can copy one of the application manifest files that come with the examples.

To embed a manifest file as a resource, you can use the rsrc tool.

IMPORTANT: If you don't embed a manifest as a resource, then you should not launch your executable before the manifest file is in place. If you do anyway, the program will not run properly. And worse, Windows will not recognize a manifest file, you later drop next to the executable. To fix this, rebuild your executable and only launch it with a manifest file in place.

Program Crashes

By default Go uses os threads with small stack sizes of 128KB. If your walk app crashes, it may be due to a stack overflow. Until a better solution is found, you can work around this by adding

import _ "runtime/cgo"

somewhere in your program. If you don't have gcc installed and on your PATH, you can alternatively add -linkmode internal to the -ldflags of your go build command like so:

go build -ldflags="-H windowsgui -linkmode internal"

CGo Optimizations

The usual default message loop includes calls to win32 API functions, which incurs a decent amount of runtime overhead coming from Go. As an alternative to this, you may compile Walk using an optional C implementation of the main message loop, by passing the walk_use_cgo build tag:

go build -tags walk_use_cgo