When running for the second time in window.CenterOnScreen(), it will get stuck when running on the main thread

[jinguihua]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

When running for the second time in window.CenterOnScreen(), it will get stuck when running on the main thread

How to reproduce

When running for the second time in window.CenterOnScreen(), it will get stuck when running on the main thread

Screenshots

When running for the second time in window.CenterOnScreen(), it will get stuck when running on the main thread

Example code

When running for the second time in window.CenterOnScreen(), it will get stuck when running on the main thread

Fyne version

2.6.1

Go compiler version

1.24.2

Operating system and version

mac os

Additional Information

No response

[andydotxyz]

There is a reason we ask the questions above, please try to fill them in appropriately.

I am not able to replicate with the given information.
For clarity, this does not get stuck:

package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	a := app.New()
	w := a.NewWindow("Hello")
	w.SetContent(widget.NewLabel("Hello Fyne!"))

	w.CenterOnScreen()
	w.CenterOnScreen()
	w.ShowAndRun()
}

[jinguihua]

There is a reason we ask the questions above, please try to fill them in appropriately.

I am not able to replicate with the given information. For clarity, this does not get stuck:

package main

import (
"fyne.io/fyne/v2/app"
"fyne.io/fyne/v2/widget"
)

func main() {
a := app.New()
w := a.NewWindow("Hello")
w.SetContent(widget.NewLabel("Hello Fyne!"))

w.CenterOnScreen()
w.CenterOnScreen()
w.ShowAndRun()
}

Thank you very much for looking into this issue!
Here’s how to reproduce the problem: I’m using a single window to display different pages.

When I call window.SetContent() for the second time to give the window a new UI, then calling window.CenterOnScreen() will cause it to block.

I’m working on a GUI framework based on Fyne, which is located here: https://github.com/any-call/myfyne

I discovered this issue while building the framework.

[andydotxyz]

Please post example code into this issue so we can reproduce it.

[jinguihua]

Please post example code into this issue so we can reproduce it.

package main

import (
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
	"log"
)

func main() {
	a := app.New()
	w := a.NewWindow("Hello")
	w.SetContent(container.NewVBox(
		widget.NewLabel("Hello Fyne!"),
		widget.NewButton("next page", func() {
			w.SetContent(container.NewVBox(
				widget.NewLabel("Hello Fyne! ,second page"),
			))
			w.SetTitle("second content")
			w.Resize(fyne.NewSize(400, 400))
			w.SetFixedSize(false)
			log.Println("run here 01")
			w.CenterOnScreen() // here  run will block
			log.Println("run here 02")
			w.Show()
		}),
	))
	w.SetTitle("first content")
	w.Resize(fyne.NewSize(300, 300))
	w.SetFixedSize(false)
	w.CenterOnScreen()
	w.Show()
	a.Run()
}

[andydotxyz]

Thanks. From that I was able to boil it down to:

package main

import (
	"log"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	a := app.New()
	w := a.NewWindow("Hello")
	w.SetContent(container.NewVBox(
		widget.NewLabel("Hello Fyne!"),
		widget.NewButton("next page", func() {
			log.Println("run here 01")
			w.CenterOnScreen() // here  run will block
			log.Println("run here 02")
		}),
	))
	w.SetTitle("first content")
	w.Resize(fyne.NewSize(300, 300))
	w.CenterOnScreen()
	w.ShowAndRun()
}

It seems that the core is running CenterOnScreen from within the button callback. Fix pending.

[andydotxyz]

That looks to be the appropriate fix - something in our thread handling change did not propagate correctly to this call internally.

[andydotxyz]

Fixed on develop for next release