Detecting loss of focus on LineEdit

[maxenko]

I've build my own widget wrapping LineEdit, which accepts text, int or float and responds to mouse-wheel for increments. Its what I need and it works well.

There is only one problem, and its with partial float input.

User doesn't always press enter when they are done. They sometimes click off the LineEdit box into another widget (or tab over to next widget), which leaves input as valid parse value for a float, but incomplete. So the value will be left like 2. or 3.00, where it should be parsed into 2 or 3.

What can I use in slint to detect focus loss on a LineEdit so that I can do one final parse of a value the same way as I do now on accepted callback (when enter is pressed)?

[ogoffart]

This is not really possible. Although there exist hack as shown in issue #112
Example

[maxenko]

That's more or less a solution, I forgot its all immediate and re-evaluates on each frame.

[bjorn]

It's not immediate and doesn't re-evaluate each frame. That example works because the change in the has-focus property triggers a re-evaluation of the conditional expression. When it became true, a Rectangle is instantiated, triggering its init callback. This callback immediately triggers the removal of that rectangle by setting was-edited to false.

So each time has-focus becomes false and was-edited is true, there is exactly one chance to perform custom logic.

The preferred solution would likely be a has-focus-changed callback, but this hack works for now.

[maxenko]

That example works because the change in the has-focus property triggers a re-evaluation of the conditional expression.

Got it, thank you. Would have kept going with this wrong assumption if you didn't elaborate.

https://snapshots.slint.dev/master/docs/slint/src/language/syntax/conditions