golang开发windows界面

在 awesome-go 节点下有不少开发界面的库, 大部分是基于web, gtk, qt跨平台的, 也有基于sciter go绑定的 go-sciter , 基于原生包装的跨平台的库 ui , 只支持Windows桌面端的 walk

个人倾向于后2个, 适合个人的技术栈, 试用了下ui这个库, demo比较 少就4个, 运行起来有点卡, 而且生成的可执行文件很大. 最重要的是不支持设置控件坐标(没找到), 而且开放的接口比较少.

下面对比下ui和walk代码, 就拿button控件来说.

• ui

type Button struct {
    ControlBase
    b   *C.uiButton
    onClicked       func(*Button)
}

type ControlBase struct {
    iface       Control
    c       *C.uiControl
}

type Control interface {
    LibuiControl() uintptr
    Destroy()
    Handle() uintptr
    Visible() bool
    Show()
    Hide()
    Enabled() bool
    Enable()
    Disable()
}

• walk

type Button struct {
    WidgetBase
    checkedChangedPublisher EventPublisher
    clickedPublisher        EventPublisher
    textChangedPublisher    EventPublisher
    imageChangedPublisher   EventPublisher
    image                   Image
    persistent              bool
}

type WidgetBase struct {
    WindowBase
    parent                      Container
    toolTipTextProperty         Property
    toolTipTextChangedPublisher EventPublisher
    graphicsEffects             *WidgetGraphicsEffectList
    alwaysConsumeSpace          bool
}

type WindowBase struct {
    window                  Window
    hWnd                    win.HWND
    origWndProcPtr          uintptr
    name                    string
    font                    *Font
    contextMenu             *Menu
    disposables             []Disposable
    disposingPublisher      EventPublisher
    dropFilesPublisher      DropFilesEventPublisher
    keyDownPublisher        KeyEventPublisher
    keyPressPublisher       KeyEventPublisher
    keyUpPublisher          KeyEventPublisher
    mouseDownPublisher      MouseEventPublisher
    mouseUpPublisher        MouseEventPublisher
    mouseMovePublisher      MouseEventPublisher
    mouseWheelPublisher     MouseEventPublisher
    boundsChangedPublisher  EventPublisher
    sizeChangedPublisher    EventPublisher
    maxSize                 Size
    minSize                 Size
    background              Brush
    cursor                  Cursor
    suspended               bool
    visible                 bool
    enabled                 bool
    name2Property           map[string]Property
    enabledProperty         Property
    enabledChangedPublisher EventPublisher
    visibleProperty         Property
    visibleChangedPublisher EventPublisher
    focusedProperty         Property
    focusedChangedPublisher EventPublisher
    calcTextSizeInfoPrev    *calcTextSizeInfo
}

只列出了属性, 没有列出方法. 但也可以看出来ui这个库开放的接口非常少. 而walk这个库, 该有的都有了, 接口非常丰富. 实现的控件非常多, 甚至连webview都有, 例子也丰富不少.

需要注意的这个库里面的控件是基于原生控件的, 而不是自己绘制的

walk使用

func main() {
    var label1, label2 *walk.Label
    mv := MainWindow{
        Title:  "go window",
        Size:   Size{Width:800, Height:600},
        Layout: VBox{MarginsZero: true},
        Children: []Widget{
            Label{Text: "Hello World", AssignTo: &label1,
                Background: SolidColorBrush{walk.RGB(255, 0, 0)},
                OnSizeChanged: func() {
                        label1.SetBounds(walk.Rectangle{100, 100, 100, 100})
            }},
            Label{Text: "Hello World", AssignTo: &label2,
                Background: SolidColorBrush{walk.RGB(0, 255, 0)},
                OnSizeChanged: func() {
                    label2.SetBounds(walk.Rectangle{100, 200, 100, 100})
            }},
        },
    }
    mv.Run()
}

有点类似flutter中的申明式构建界面, 但是没有提供代码初始化的回调^^.

win使用

walk内部调用了win, 而win就干了一件事, 把win32 api几乎所有相关的声明都导成了go.

比如win32里面的ShowWindow, 是这么导出的:

func init() {
        libuser32 = MustLoadLibrary("user32.dll")
        ....
        showWindow = MustGetProcAddress(libuser32, "ShowWindow")
}

func ShowWindow(hWnd HWND, nCmdShow int32) bool {
    ret, _, _ := syscall.Syscall(showWindow, 2,
        uintptr(hWnd),
        uintptr(nCmdShow),
        0)

    return ret != 0
}

这样我们用 go 来调用win32 api, 跟c基本没差别, 除了语法上的略微差别. 我试用了下, 还是有个把方法没有导出. 可以按照这个方式自己导出.

既然该有的win32接口都有了, 那么就用go创建一个最简单的windows窗口吧

func main() {
    hInst := GetModuleHandle(nil)
    hIcon := LoadIcon(0, MAKEINTRESOURCE(IDI_APPLICATION))
    hCursor := LoadCursor(0, MAKEINTRESOURCE(IDC_ARROW))

    var wc WNDCLASSEX
    wc.CbSize = uint32(unsafe.Sizeof(wc))
    wc.LpfnWndProc = syscall.NewCallback(wndProc)
    wc.HInstance = hInst
    wc.HIcon = hIcon
    wc.HCursor = hCursor
    wc.HbrBackground = COLOR_WINDOW + 1
    wc.LpszClassName = syscall.StringToUTF16Ptr("go windwow")
    wc.Style = CS_HREDRAW | CS_VREDRAW
    RegisterClassEx(&wc)

    hWnd := CreateWindowEx(
        0,
        syscall.StringToUTF16Ptr("go windwow"),
        syscall.StringToUTF16Ptr("go windwow"),
        WS_OVERLAPPEDWINDOW,
        400,
        200,
        640,
        480,
        0,
        0,
        hInst,
        nil)
    ShowWindow(hWnd, SW_SHOW)
    UpdateWindow(hWnd)

    var msg MSG
    for {
        if (GetMessage(&msg, 0, 0, 0) == TRUE) {
            TranslateMessage(&msg)
            DispatchMessage(&msg)
        } else {
            break
        }
    }
}

func wndProc(hwnd HWND, msg uint32, wParam, lParam uintptr) (result uintptr) {
    var ps PAINTSTRUCT
    switch msg {
    case WM_PAINT:
        hdc := BeginPaint(hwnd, &ps)

        var lb LOGBRUSH
        lb.LbStyle = BS_SOLID
        lb.LbColor = 0xff000
        lb.LbHatch = 0

        hPen := HGDIOBJ(ExtCreatePen(PS_SOLID, 2, &lb, 0, nil))
        hOldOpen := SelectObject(hdc, hPen)

        var pt POINT
        MoveToEx(hdc, 0, 0, &pt)
        LineTo(hdc, 100, 100)
        EndPaint(hwnd, &ps)

        SelectObject(hdc, hOldOpen)
        DeleteObject(hPen)
        break
    case WM_DESTROY:
        PostQuitMessage(0)
        break
    default:
        return DefWindowProc(hwnd, msg, wParam, lParam)
    }
    return 0
}

是不是基本与c的写法一模一样, 包括命名. 因此用go(win), 也能像c/c++一样开发windows界面, 只用稍微切换下语法.

而walk虽然把传统win32 api和控件封装成了对象, 把基于消息的事件包装成了回调, 封装出了canvs, 也有布局容器BoxLayout, 做做简单的界面还是很方便的, 但是其本质还是基于windows原有控件, 想自由布局, 定制界面, 性能方面还是很受限.

个人感觉可以win为基础封装自己的库, 比如用go把duilib翻译一遍, 这就又是另一番苦力活了.

网上干类似事情的库: