addListener method
添加监听
Implementation
void addListener({
required String key,
required EventCallback callback,
}) {
if (_events[key] != null) {
_events[key] = [..._events[key]!, callback];
} else {
_events[key] = [callback];
}
}
添加监听
void addListener({
required String key,
required EventCallback callback,
}) {
if (_events[key] != null) {
_events[key] = [..._events[key]!, callback];
} else {
_events[key] = [callback];
}
}