qt gui update elements not working with Golang

Question

I'm attempting to make a form update a WebView in QML however I'm having issues updating the view and text using GoLang.

I've looked at similar posts such as this one and this one, but it is still no clear.

As you can see below, I'm trying to update the WebView to change the page shown, and the Text element so I can see for my own sake what is being stored when I press the button. However the GUI doesn't change.

What I've got so far is this:

package main

import (
    "time"
    "math/rand"
    "fmt"
    "os"
    "gopkg.in/qml.v1"
)

type Control struct {
    Root    qml.Object
    Message string
}

func (ctrl *Control) Savetf1contents(text qml.Object) {
        fmt.Println("in Savetf1contents():")
        fmt.Println("text:", text.String("text"))
}

func (ctrl *Control) Loadtf1contents(text qml.Object) {
        fmt.Println("in Loadtf1contents():")
        fmt.Println("text:", text.String("text"))
        go func() {
            ctrl.Message = "loaded from tf1..."
            qml.Changed(ctrl, &ctrl.Message)
        }()
}




func main() {
    if err := qml.Run(run); err != nil {
        fmt.Fprintf(os.Stderr, "error: %v\n", err)
        os.Exit(1)
    }
}

func run() error {
    // qml.RegisterTypes("GoExtensions", 1, 0, []qml.TypeSpec{{
    //  Init: func(r *GoRect, obj qml.Object) { r.Object = obj },
    // }})

    engine := qml.NewEngine()
    component, err := engine.LoadFile("helloworld.qml")
    if err != nil {
        return err
    }

    ctrl := Control{Message: "http://google.co.uk"}

    context := engine.Context()
    context.SetVar("ctrl", &ctrl)

    window := component.CreateWindow(nil)
    ctrl.Root = window.Root()
    rand.Seed(time.Now().Unix())


    window.Show()
    window.Wait()

    return nil
}

and the QML file:

import QtQuick 2.2
import QtQuick.Controls 1.1
import QtQuick.Window 2.0
import QtWebKit 3.0

ApplicationWindow {
    //property alias form: ctrl.message

    title: qsTr("Dashboard")
    width: 640
    height: 480

    menuBar: MenuBar {
        Menu {
            title: qsTr("File")
            MenuItem {
                text: qsTr("Exit")
                onTriggered: Qt.quit();
            }
        }
    }

    Grid {
        columns: 3
        spacing: 2

        Text {
            width: 335
            // text: qsTr("Dashboard")
            text: qsTr(ctrl.message)
        }

        Rectangle{
            width: 200
            height: 30
            radius: 3
            color: "#fff"
            TextInput {
                id: form
                anchors.left: parent.right
                anchors.top: parent.top
                anchors.leftMargin: -195
                anchors.topMargin: 5
                text: qsTr("")
                focus: true
                width: 200
            }
        }
        Button {
            text: qsTr("Search User")
            onClicked: {
                ctrl.savetf1contents(form)
            }
        }

    }

    Grid {
        columns: 1
        spacing: 2
        anchors.top: parent.top
        anchors.topMargin: 35
        id: text
        WebView {
             id: frame
             url: ctrl.message
             width: 640
             height: 300
             smooth: false
         }

    }

}

Answer 1

This example should change the text element, and manipulate the webview to load new page based on the user input:

func (ctrl *Control) Savetf1contents(text qml.Object) 
{
    fmt.Println("in Savetf1contents():")
    fmt.Println("text:", text.String("text"))
    // Change the message & update
    ctrl.Message = text.String("text")
    qml.Changed(ctrl, &ctrl.Message)
    // Find the webview element
    webframe := ctrl.Root.ObjectByName("tralalala")
    // Load new page!
    webframe.Set("url", text.String("text"))
}

In order for this to work, you have to set the objectName property for the webview component:

WebView 
{
    objectName: "tralalala"
    id: frame
    url: ctrl.message
    width: 640
    height: 300
    smooth: false
}

In case your intent was to manipulate the content of webview (for filling out the search form), that is not possible by using the public api. However, you can always manipulate the url to contain your search terms.