Updating Content in your GUI
Having completed the hello world tutorial or other examples you will have created a basic user interface. In this page we see how the content of a GUI can be updated from your code.
The first step is to assign the widget you want to update to a
variable. In the hello world tutorial we passed widget.NewLabel
directly into SetContent(), to update it we change that to two
different lines, such as:
message := widget.NewLabel("Welcome")
w.SetContent(message)
Once the content has been assigned to a variable we can call functions
like SetText("new text"). For our example we will set the
content of our label to the current time, with the help of
Time.Format.
formatted := time.Now().Format("Time: 03:04:05")
message.SetText(formatted)
That is all we need to do to change content of a visible item (see below for the full code). In the following example we put that code into a button tap - now each time the button is tapped the time will be displayed in the Label widget.
Full example
The full code is as follows:
package main
import (
"time"
"fyne.io/fyne/v2/app"
"fyne.io/fyne/v2/container"
"fyne.io/fyne/v2/widget"
)
func main() {
a := app.New()
w := a.NewWindow("Update Time")
message := widget.NewLabel("Welcome")
button := widget.NewButton("Update", func() {
formatted := time.Now().Format("Time: 03:04:05")
message.SetText(formatted)
})
w.SetContent(container.NewVBox(message, button))
w.ShowAndRun()
}