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rui/focusEvents.go

161 lines
3.7 KiB
Go

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 valueToFocusListeners(value interface{}) ([]func(View), bool) {
if value == nil {
return nil, true
}
switch value := value.(type) {
case func(View):
return []func(View){value}, true
case func():
fn := func(View) {
value()
}
return []func(View){fn}, true
case []func(View):
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(View), count)
for i, v := range value {
if v == nil {
return nil, false
}
listeners[i] = func(View) {
v()
}
}
return listeners, true
case []interface{}:
count := len(value)
if count == 0 {
return nil, true
}
listeners := make([]func(View), count)
for i, v := range value {
if v == nil {
return nil, false
}
switch v := v.(type) {
case func(View):
listeners[i] = v
case func():
listeners[i] = func(View) {
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 interface{}) bool {
listeners, ok := valueToFocusListeners(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 subviewID != "" {
view = ViewByID(view, subviewID)
}
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 "" 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 "" then a value from the first argument (view) is returned.
func GetLostFocusListeners(view View, subviewID string) []func(View) {
return getFocusListeners(view, subviewID, LostFocusEvent)
}