ThreeStateBox

Represent a control with three states (checked, unckehed or unknown):

To create a threestatebox use ThreeStateBox::new method (with 3 parameters: a caption, a layout and a state (checked, unchecked or unknown)).

let b = ThreeStateBox::new("A ThreeStateBox", Layout::new("x:10,y:5,w:15"),threestatebox::State::Checked);

or the macro threestatebox!

let c1 = threestatebox!("caption='Some option',x:10,y:5,w:15,h:1");
let c2 = threestatebox!("'Another &option',x:10,y:5,w:15,h:1,state:checked");
let c3 = threestatebox!("'&Multi-line option\nthis a hot-key',x:10,y:5,w:15,h:3,state:unknown");
let c4 = threestatebox!("'&Unchecked threestatebox',x:10,y:5,w:15,h:3,state:unchecked");

The caption of a threestatebox may contain the special character & that indicates that the next character is a hot-key. For example, constructing a threestatebox with the following caption &Option number 1 will set up the text of the button to Option number 1 and will set up character O as the hot key for that threestatebox (pressing Alt+O will be equivalent to changing the status for that threestatebox from checked to unchecked to unkown).

A threestatebox can contain a multi-line text but you will have to set the height parameter large enough to a larger value (bigger than 1).

A threestatebox supports all common parameters (as they are described in Instantiate via Macros section). Besides them, the following named parameters are also accepted:

Some examples that uses these paramateres:

let disabled_threestatebox = threestatebox!("caption=&Disabled,x:10,y:5,w:15,enable=false");
let hidden_threestatebox = threestatebox!("text='&Hidden',x=9,y:1,align:center,w:9,visible=false");
let multi_line_threestatebox = threestatebox!("'&Multi line\nLine2\nLine3',x:1,y:1,w:10,h:3");
let custom_type_threestatebox = threestatebox!("'&Custom type',x:1,y:1,w:10,h:1,type=YesNo");

The type of the ThreeStateBox describes how the ThreeStateBox state (checked , unchecked or unknown) will be represented on the screen.

Events

To intercept events from a threestatebox, the following trait has to be implemented to the Window that processes the event loop:

pub trait ThreeStateBoxEvents {
    fn on_status_changed(&mut self, handle: Handle<ThreeStateBoxEvents>, state: threestatebox::State) -> EventProcessStatus {...}
}

Methods

Besides the Common methods for all Controls a checkbox also has the following aditional methods:

Key association

The following keys are processed by the control if it has focus:

Aditionally, Alt+letter or number will have the same action (even if the threestatebox does not have a focus) if that letter or nunber was set as a hot-key for a threestatebox via its caption.

Example

The following code creates a window a threestatebox and a label. Whenever the threestatebox status is being changed, the label will print the new status (checked, unchecked or unkown).

#[Window(events = ThreeStateBoxEvents)]
struct MyWin {
    c: Handle<ThreeStateBox>,
    l: Handle<Label>,
}

impl MyWin {
    fn new() -> Self {
        let mut win = MyWin {
            base: window!("'My Win',d:c,w:40,h:6"),
            c: Handle::None,
            l: Handle::None,
        };
        win.c = win.add(threestatebox!("'My option',l:1,r:1,b:1"));
        win.l = win.add(label!("'State: Unknown',l:1,r:1,t:1"));
        win
    }
}

impl ThreeStateBoxEvents for MyWin {
    fn on_status_changed(&mut self, _handle: Handle<ThreeStateBox>, state: State) -> EventProcessStatus {
        let handle = self.l;
        let l = self.control_mut(handle).unwrap();
        match state {
            State::Checked => l.set_caption("State: Checked"),
            State::Unchecked => l.set_caption("State: Unchecked"),
            State::Unknown => l.set_caption("State: Unknown"),
        }
        EventProcessStatus::Processed
    }
}

fn main() -> Result<(), appcui::system::Error> {
    let mut app = App::new().build()?;
    app.add_window(MyWin::new());
    app.run();
    Ok(())
}