onSelectionChanged method
Unlike addListener, this only calls block
when the selection of
text actually changes. This won't be invoked when the focus or text
value of the text changes in TextField or TextFormField.
Returns Disposable function which can be called to dispose this listener.
Implementation
Disposable onSelectionChanged(void Function(TextSelection selection) block) {
var previousValue = selection;
void onSelectionChanged() {
if (selection != previousValue) {
block(selection);
}
previousValue = selection;
}
addListener(onSelectionChanged);
return () => removeListener(onSelectionChanged);
}