clui/radio.go

151 lines
3.6 KiB
Go

package clui
import (
xs "github.com/huandu/xstrings"
term "github.com/nsf/termbox-go"
)
/*
Radio button control. Unite a few radios in one radio group to
make a user select one of available choices.
*/
type Radio struct {
BaseControl
group *RadioGroup
selected bool
onChange func(bool)
}
/*
CreateRadio creates a new radio button.
view - is a View that manages the control
parent - is container that keeps the control. The same View can be a view and a parent at the same time.
width - is minimal width of the control.
title - radio title.
scale - the way of scaling the control when the parent is resized. Use DoNotScale constant if the
control should keep its original size.
*/
func CreateRadio(parent Control, width int, title string, scale int) *Radio {
c := new(Radio)
c.BaseControl = NewBaseControl()
if width == AutoSize {
width = xs.Len(title) + 4
}
c.parent = parent
c.SetSize(width, 1) // TODO: only one line heigth is supported at that moment
c.SetConstraints(width, 1)
c.SetTitle(title)
c.SetTabStop(true)
c.SetScale(scale)
c.onChange = nil
if parent != nil {
parent.AddChild(c)
}
return c
}
// Draw repaints the control on its View surface
func (c *Radio) Draw() {
if c.hidden {
return
}
PushAttributes()
defer PopAttributes()
x, y := c.Pos()
w, h := c.Size()
fg, bg := RealColor(c.fg, c.Style(), ColorControlText), RealColor(c.bg, c.Style(), ColorControlBack)
if !c.Enabled() {
fg, bg = RealColor(c.fg, c.Style(), ColorControlDisabledText), RealColor(c.bg, c.Style(), ColorControlDisabledBack)
} else if c.Active() {
fg, bg = RealColor(c.fg, c.Style(), ColorControlActiveText), RealColor(c.bg, c.Style(), ColorControlActiveBack)
}
parts := []rune(SysObject(ObjRadio))
cOpen, cClose, cEmpty, cCheck := parts[0], parts[1], parts[2], parts[3]
cState := cEmpty
if c.selected {
cState = cCheck
}
SetTextColor(fg)
SetBackColor(bg)
FillRect(x, y, w, h, ' ')
if w < 3 {
return
}
PutChar(x, y, cOpen)
PutChar(x+2, y, cClose)
PutChar(x+1, y, cState)
if w < 5 {
return
}
shift, text := AlignColorizedText(c.title, w-4, c.align)
DrawText(x+4+shift, y, text)
}
// ProcessEvent processes all events come from the control parent. If a control
// processes an event it should return true. If the method returns false it means
// that the control do not want or cannot process the event and the caller sends
// the event to the control parent.
// The control processes only space button and mouse clicks to make control selected.
// Deselecting control is not possible: one has to click another radio of the radio
// group to deselect this button
func (c *Radio) ProcessEvent(event Event) bool {
if (!c.Active() && event.Type == EventKey) || !c.Enabled() {
return false
}
if (event.Type == EventKey && event.Key == term.KeySpace) || event.Type == EventClick {
if c.group == nil {
c.SetSelected(true)
} else {
c.group.SelectItem(c)
}
return true
}
return false
}
// SetSelected makes the button selected. One should not use
// the method directly, it is for RadioGroup control
func (c *Radio) SetSelected(val bool) {
c.selected = val
if c.onChange != nil {
go c.onChange(val)
}
}
// Selected returns if the radio is selected
func (c *Radio) Selected() bool {
return c.selected
}
// SetGroup sets the radio group to which the radio belongs
func (c *Radio) SetGroup(group *RadioGroup) {
c.group = group
}
// OnChange sets the callback that is called whenever the state
// of the Radio is changed. Argument of callback is the current
func (c *Radio) OnChange(fn func(bool)) {
c.mtx.Lock()
defer c.mtx.Unlock()
c.onChange = fn
}