dongsutao8921 2014-04-09 11:04
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如何使用gtk.go.Connect()设置一个带参数的插槽(事件处理程序)?

I am using GTK bindings for Go.

Trying to connect a gtk.RadioButton toggle signal to a function. This code works fine:

...

radioButton.Connect("toggled", doRadioToggle)

func doRadioToggle() {
    fmt.Println("toggled")
}

...

When radioButton is toggled, doRadioToggle is called - Good.


But I want to connect to a function that takes a parameter, for example:

func doRadioToggle(button *gtk.RadioButton) {
    fmt.Println(button.GetState())
}

The gtk.go.Connect() function has this signature:

func (v *Widget) Connect(s string, f interface{}, datas ...interface{})

Based on what I know from gtkmm, I tried code like this (the go binding has apparently greatly simplified the call to connect())

radioButton.Connect("toggled", doRadioToggle, radioButton)

The third argument passed inconnect() - radioButton - corresponding todatasin

gtk.Connect(s string, f interface{}, datas ...interface{})

which I understood to mean data arguments to be passed to the slot.

But with this code, the doRadioToggle() handler never gets called, and I immediately exit with a panic:

panic: reflect: Call using *glib.CallbackContext as type *gtk.RadioButton

My question: How do I set up slot (event handler) that takes parameters using gtk.go.Connect()?

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  • doukan1258 2014-04-11 02:21
    关注

    Based on response from the amazing mattn on GitHub:

    https://github.com/mattn/go-gtk/blob/master/example/demo/demo.go#L58

    Adopted, tested and working:

    import(
    ... 
    "github.com/mattn/go-gtk/glib"
    )
    
    ...
    
    func ButtonHandler(ctx *glib.CallbackContext) {
        fmt.Printf("Button Handler: %v
    ", ctx.Data().(*gtk.RadioButton).GetState())
    }
    
    aRadioButton.Connect("toggled", ButtonHandler, aRadioButton)
    
    ...
    

    Thedatasarguments inconnect()must be passed using*glib.CallbackContext in the handler's signature, then, in the handler code, use type assertion to grab the actual arguments .

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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