package rui import "strings" const ( // FocusEvent is the constant for "focus-event" property tag. // The "focus-event" event occurs when the View takes input focus. // The main listener format: // func(View). // The additional listener format: // func(). FocusEvent = "focus-event" // LostFocusEvent is the constant for "lost-focus-event" property tag. // The "lost-focus-event" event occurs when the View lost input focus. // The main listener format: // func(View). // The additional listener format: // func(). LostFocusEvent = "lost-focus-event" ) func valueToNoParamListeners[V any](value any) ([]func(V), bool) { if value == nil { return nil, true } switch value := value.(type) { case func(V): return []func(V){value}, true case func(): fn := func(V) { value() } return []func(V){fn}, true case []func(V): if len(value) == 0 { return nil, true } for _, fn := range value { if fn == nil { return nil, false } } return value, true case []func(): count := len(value) if count == 0 { return nil, true } listeners := make([]func(V), count) for i, v := range value { if v == nil { return nil, false } listeners[i] = func(V) { v() } } return listeners, true case []any: count := len(value) if count == 0 { return nil, true } listeners := make([]func(V), count) for i, v := range value { if v == nil { return nil, false } switch v := v.(type) { case func(V): listeners[i] = v case func(): listeners[i] = func(V) { v() } default: return nil, false } } return listeners, true } return nil, false } var focusEvents = map[string]struct{ jsEvent, jsFunc string }{ FocusEvent: {jsEvent: "onfocus", jsFunc: "focusEvent"}, LostFocusEvent: {jsEvent: "onblur", jsFunc: "blurEvent"}, } func (view *viewData) setFocusListener(tag string, value any) bool { listeners, ok := valueToNoParamListeners[View](value) if !ok { notCompatibleType(tag, value) return false } if listeners == nil { view.removeFocusListener(tag) } else if js, ok := focusEvents[tag]; ok { view.properties[tag] = listeners if view.created { updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)", view.Session()) } } else { return false } return true } func (view *viewData) removeFocusListener(tag string) { delete(view.properties, tag) if view.created { if js, ok := focusEvents[tag]; ok { removeProperty(view.htmlID(), js.jsEvent, view.Session()) } } } func getFocusListeners(view View, subviewID []string, tag string) []func(View) { if len(subviewID) > 0 && subviewID[0] != "" { view = ViewByID(view, subviewID[0]) } if view != nil { if value := view.Get(tag); value != nil { if result, ok := value.([]func(View)); ok { return result } } } return []func(View){} } func focusEventsHtml(view View, buffer *strings.Builder) { if view.Focusable() { for _, js := range focusEvents { buffer.WriteString(js.jsEvent + `="` + js.jsFunc + `(this, event)" `) } } } // GetFocusListeners returns a FocusListener list. If there are no listeners then the empty list is returned // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned. func GetFocusListeners(view View, subviewID ...string) []func(View) { return getFocusListeners(view, subviewID, FocusEvent) } // GetLostFocusListeners returns a LostFocusListener list. If there are no listeners then the empty list is returned // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned. func GetLostFocusListeners(view View, subviewID ...string) []func(View) { return getFocusListeners(view, subviewID, LostFocusEvent) }