Trait RowSource 

pub trait RowSource {
    // Required methods
    fn len(&self) -> usize;
    fn key_at(&self, index: usize) -> Option<String>;
    fn index_of(&self, key: &str) -> Option<usize>;
    fn request_range(&mut self, range: Range<usize>);
    fn read(
        &mut self,
        key: &str,
        read: &mut dyn FnMut(&mut dyn Source) -> Result<(), String>,
    ) -> Result<bool, String>;
    fn key_presenting(&self, id: &str) -> Option<String>;
    fn take_changes(&mut self) -> Vec<ListModelChange<String>>;
    fn has_changes(&self) -> bool;

    // Provided method
    fn is_empty(&self) -> bool { ... }
}

Rows its host renders only when the widget shows them: a loop over ten thousand items costs the rows on screen. The host keeps the keys of every row, renders the rows the widget asks for and forgets the others, and queues what changed (rows inserted, removed or moved, and rendered rows that show something else now) for the widget to take.

Required Methods

fn len(&self) -> usize

How many rows there are, rendered or not.

fn key_at(&self, index: usize) -> Option<String>

The key of the row at index.

fn index_of(&self, key: &str) -> Option<usize>

Where the row key stands.

fn request_range(&mut self, range: Range<usize>)

Render the rows of range not rendered yet, and forget those rendered outside it.

fn read( &mut self, key: &str, read: &mut dyn FnMut(&mut dyn Source) -> Result<(), String>, ) -> Result<bool, String>

Read the rendered row key as an instance of a component: Ok(false) when it is not rendered.

Errors

What read returned.

fn key_presenting(&self, id: &str) -> Option<String>

The key of the row showing the resource id, rendered or not.

fn take_changes(&mut self) -> Vec<ListModelChange<String>>

What changed since it was asked last, each change against the rows the one before it left.

fn has_changes(&self) -> bool

Whether changes are waiting.

Provided Methods

fn is_empty(&self) -> bool

Implementors