Trait App 

pub trait App {
    // Required method
    fn frame(&mut self, ui: &mut Ui);

    // Provided methods
    fn actions(&self) -> &'static [ActionSpec] { ... }
    fn action_revision(&self) -> Option<u64> { ... }
    fn action_available(&self, _spec: &ActionSpec) -> Result<(), ActionError> { ... }
    fn action(
        &mut self,
        _ui: &mut Ui,
        _spec: &ActionSpec,
        _input: &Value,
        _context: &ActionContext,
    ) -> Result<ActionResult, ActionError> { ... }
    fn action_inspect(&self, _query: &Value) -> Result<Value, ActionError> { ... }
    fn action_resource_info(&self, _uri: &str) -> Result<Resource, ActionError> { ... }
    fn action_resource_read(
        &self,
        _uri: &str,
        _offset: u64,
        _limit: usize,
    ) -> Result<Vec<u8>, ActionError> { ... }
    fn init(&mut self, _ui: &mut Ui) -> bool { ... }
    fn command(&mut self, _ui: &mut Ui, _id: u32, _arg: u32) -> bool { ... }
}

the app’s callbacks (APP_DESC on_init, on_frame, on_command)

Required Methods

fn frame(&mut self, ui: &mut Ui)

builds the UI (every pass; no side effects except through widgets)

Provided Methods

fn actions(&self) -> &'static [ActionSpec]

Optional domain actions, in addition to the universal UI action catalogue.

fn action_revision(&self) -> Option<u64>

Domain revision. None uses the UI runtime’s own: it moves with the controls (their set, labels, values and states, the focus, an open modal dialog, the title, enabled commands) and with every agent call that changes something, not with frames or the pointer, and it knows nothing of a change the user makes to the app’s data.

fn action_available(&self, _spec: &ActionSpec) -> Result<(), ActionError>

Dynamic domain constraints such as read-only files or an absent selection.

fn action( &mut self, _ui: &mut Ui, _spec: &ActionSpec, _input: &Value, _context: &ActionContext, ) -> Result<ActionResult, ActionError>

Domain action handler; adapters should call the same editing functions as the GUI.

fn action_inspect(&self, _query: &Value) -> Result<Value, ActionError>

Filtered domain state; the default universal inspection includes the widget tree.

fn action_resource_info(&self, _uri: &str) -> Result<Resource, ActionError>

Describe an application-owned binary resource returned by one of its actions.

fn action_resource_read( &self, _uri: &str, _offset: u64, _limit: usize, ) -> Result<Vec<u8>, ActionError>

Read a bounded byte range of an application-owned resource, never an arbitrary path.

fn init(&mut self, _ui: &mut Ui) -> bool

called before the first frame; false = initialisation failed (exit code 2)

fn command(&mut self, _ui: &mut Ui, _id: u32, _arg: u32) -> bool

commands queued with ui.cmd_run and the built-in UIC_* ids; true = handled

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors