nt

checkbox.go (9695B)

---

 package tview
 
 import (
 	"github.com/gdamore/tcell/v2"
 )
 
 // Checkbox implements a simple box for boolean values which can be checked and
 // unchecked.
 //
 // See https://github.com/rivo/tview/wiki/Checkbox for an example.
 type Checkbox struct {
 	*Box
 
 	// Whether or not this checkbox is disabled/read-only.
 	disabled bool
 
 	// Whether or not this box is checked.
 	checked bool
 
 	// The text to be displayed before the input area.
 	label string
 
 	// The screen width of the label area. A value of 0 means use the width of
 	// the label text.
 	labelWidth int
 
 	// The label style.
 	labelStyle tcell.Style
 
 	// The style of the unchecked checkbox.
 	uncheckedStyle tcell.Style
 
 	// The style of the checked checkbox.
 	checkedStyle tcell.Style
 
 	// Teh style of the checkbox when it is currently focused.
 	focusStyle tcell.Style
 
 	// The string used to display an unchecked box.
 	uncheckedString string
 
 	// The string used to display a checked box.
 	checkedString string
 
 	// An optional function which is called when the user changes the checked
 	// state of this checkbox.
 	changed func(checked bool)
 
 	// An optional function which is called when the user indicated that they
 	// are done entering text. The key which was pressed is provided (tab,
 	// shift-tab, or escape).
 	done func(tcell.Key)
 
 	// A callback function set by the Form class and called when the user leaves
 	// this form item.
 	finished func(tcell.Key)
 }
 
 // NewCheckbox returns a new input field.
 func NewCheckbox() *Checkbox {
 	return &Checkbox{
 		Box:             NewBox(),
 		labelStyle:      tcell.StyleDefault.Foreground(Styles.SecondaryTextColor),
 		uncheckedStyle:  tcell.StyleDefault.Background(Styles.ContrastBackgroundColor).Foreground(Styles.PrimaryTextColor),
 		checkedStyle:    tcell.StyleDefault.Background(Styles.ContrastBackgroundColor).Foreground(Styles.PrimaryTextColor),
 		focusStyle:      tcell.StyleDefault.Background(Styles.PrimaryTextColor).Foreground(Styles.ContrastBackgroundColor),
 		uncheckedString: " ",
 		checkedString:   "X",
 	}
 }
 
 // SetChecked sets the state of the checkbox. This also triggers the "changed"
 // callback if the state changes with this call.
 func (c *Checkbox) SetChecked(checked bool) *Checkbox {
 	if c.checked != checked {
 		if c.changed != nil {
 			c.changed(checked)
 		}
 		c.checked = checked
 	}
 	return c
 }
 
 // IsChecked returns whether or not the box is checked.
 func (c *Checkbox) IsChecked() bool {
 	return c.checked
 }
 
 // SetLabel sets the text to be displayed before the input area.
 func (c *Checkbox) SetLabel(label string) *Checkbox {
 	c.label = label
 	return c
 }
 
 // GetLabel returns the text to be displayed before the input area.
 func (c *Checkbox) GetLabel() string {
 	return c.label
 }
 
 // SetLabelWidth sets the screen width of the label. A value of 0 will cause the
 // primitive to use the width of the label string.
 func (c *Checkbox) SetLabelWidth(width int) *Checkbox {
 	c.labelWidth = width
 	return c
 }
 
 // SetLabelColor sets the color of the label.
 func (c *Checkbox) SetLabelColor(color tcell.Color) *Checkbox {
 	c.labelStyle = c.labelStyle.Foreground(color)
 	return c
 }
 
 // SetLabelStyle sets the style of the label.
 func (c *Checkbox) SetLabelStyle(style tcell.Style) *Checkbox {
 	c.labelStyle = style
 	return c
 }
 
 // SetFieldBackgroundColor sets the background color of the input area.
 func (c *Checkbox) SetFieldBackgroundColor(color tcell.Color) *Checkbox {
 	c.uncheckedStyle = c.uncheckedStyle.Background(color)
 	c.checkedStyle = c.checkedStyle.Background(color)
 	c.focusStyle = c.focusStyle.Foreground(color)
 	return c
 }
 
 // SetFieldTextColor sets the text color of the input area.
 func (c *Checkbox) SetFieldTextColor(color tcell.Color) *Checkbox {
 	c.uncheckedStyle = c.uncheckedStyle.Foreground(color)
 	c.checkedStyle = c.checkedStyle.Foreground(color)
 	c.focusStyle = c.focusStyle.Background(color)
 	return c
 }
 
 // SetUncheckedStyle sets the style of the unchecked checkbox.
 func (c *Checkbox) SetUncheckedStyle(style tcell.Style) *Checkbox {
 	c.uncheckedStyle = style
 	return c
 }
 
 // SetCheckedStyle sets the style of the checked checkbox.
 func (c *Checkbox) SetCheckedStyle(style tcell.Style) *Checkbox {
 	c.checkedStyle = style
 	return c
 }
 
 // SetActivatedStyle sets the style of the checkbox when it is currently
 // focused.
 func (c *Checkbox) SetActivatedStyle(style tcell.Style) *Checkbox {
 	c.focusStyle = style
 	return c
 }
 
 // SetCheckedString sets the string to be displayed when the checkbox is
 // checked (defaults to "X"). The string may contain color tags (consider
 // adapting the checkbox's various styles accordingly). See [Escape] in
 // case you want to display square brackets.
 func (c *Checkbox) SetCheckedString(checked string) *Checkbox {
 	c.checkedString = checked
 	return c
 }
 
 // SetUncheckedString sets the string to be displayed when the checkbox is
 // not checked (defaults to the empty space " "). The string may contain color
 // tags (consider adapting the checkbox's various styles accordingly). See
 // [Escape] in case you want to display square brackets.
 func (c *Checkbox) SetUncheckedString(unchecked string) *Checkbox {
 	c.uncheckedString = unchecked
 	return c
 }
 
 // SetFormAttributes sets attributes shared by all form items.
 func (c *Checkbox) SetFormAttributes(labelWidth int, labelColor, bgColor, fieldTextColor, fieldBgColor tcell.Color) FormItem {
 	c.labelWidth = labelWidth
 	c.SetLabelColor(labelColor)
 	c.backgroundColor = bgColor
 	c.SetFieldTextColor(fieldTextColor)
 	c.SetFieldBackgroundColor(fieldBgColor)
 	return c
 }
 
 // GetFieldWidth returns this primitive's field width.
 func (c *Checkbox) GetFieldWidth() int {
 	return 1
 }
 
 // GetFieldHeight returns this primitive's field height.
 func (c *Checkbox) GetFieldHeight() int {
 	return 1
 }
 
 // SetDisabled sets whether or not the item is disabled / read-only.
 func (c *Checkbox) SetDisabled(disabled bool) FormItem {
 	c.disabled = disabled
 	if c.finished != nil {
 		c.finished(-1)
 	}
 	return c
 }
 
 // SetChangedFunc sets a handler which is called when the checked state of this
 // checkbox was changed. The handler function receives the new state.
 func (c *Checkbox) SetChangedFunc(handler func(checked bool)) *Checkbox {
 	c.changed = handler
 	return c
 }
 
 // SetDoneFunc sets a handler which is called when the user is done using the
 // checkbox. The callback function is provided with the key that was pressed,
 // which is one of the following:
 //
 //   - KeyEscape: Abort text input.
 //   - KeyTab: Move to the next field.
 //   - KeyBacktab: Move to the previous field.
 func (c *Checkbox) SetDoneFunc(handler func(key tcell.Key)) *Checkbox {
 	c.done = handler
 	return c
 }
 
 // SetFinishedFunc sets a callback invoked when the user leaves this form item.
 func (c *Checkbox) SetFinishedFunc(handler func(key tcell.Key)) FormItem {
 	c.finished = handler
 	return c
 }
 
 // Focus is called when this primitive receives focus.
 func (c *Checkbox) Focus(delegate func(p Primitive)) {
 	// If we're part of a form and this item is disabled, there's nothing the
 	// user can do here so we're finished.
 	if c.finished != nil && c.disabled {
 		c.finished(-1)
 		return
 	}
 
 	c.Box.Focus(delegate)
 }
 
 // Draw draws this primitive onto the screen.
 func (c *Checkbox) Draw(screen tcell.Screen) {
 	c.Box.DrawForSubclass(screen, c)
 
 	// Prepare
 	x, y, width, height := c.GetInnerRect()
 	rightLimit := x + width
 	if height < 1 || rightLimit <= x {
 		return
 	}
 
 	// Draw label.
 	_, labelBg, _ := c.labelStyle.Decompose()
 	if c.labelWidth > 0 {
 		labelWidth := c.labelWidth
 		if labelWidth > width {
 			labelWidth = width
 		}
 		printWithStyle(screen, c.label, x, y, 0, labelWidth, AlignLeft, c.labelStyle, labelBg == tcell.ColorDefault)
 		x += labelWidth
 		width -= labelWidth
 	} else {
 		_, _, drawnWidth := printWithStyle(screen, c.label, x, y, 0, width, AlignLeft, c.labelStyle, labelBg == tcell.ColorDefault)
 		x += drawnWidth
 		width -= drawnWidth
 	}
 
 	// Draw checkbox.
 	str := c.uncheckedString
 	style := c.uncheckedStyle
 	if c.checked {
 		str = c.checkedString
 		style = c.checkedStyle
 	}
 	if c.disabled {
 		style = style.Background(c.backgroundColor)
 	}
 	if c.HasFocus() {
 		style = c.focusStyle
 	}
 	printWithStyle(screen, str, x, y, 0, width, AlignLeft, style, c.disabled)
 }
 
 // InputHandler returns the handler for this primitive.
 func (c *Checkbox) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) {
 	return c.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) {
 		if c.disabled {
 			return
 		}
 
 		// Process key event.
 		switch key := event.Key(); key {
 		case tcell.KeyRune, tcell.KeyEnter: // Check.
 			if key == tcell.KeyRune && event.Rune() != ' ' {
 				break
 			}
 			c.checked = !c.checked
 			if c.changed != nil {
 				c.changed(c.checked)
 			}
 		case tcell.KeyTab, tcell.KeyBacktab, tcell.KeyEscape: // We're done.
 			if c.done != nil {
 				c.done(key)
 			}
 			if c.finished != nil {
 				c.finished(key)
 			}
 		}
 	})
 }
 
 // MouseHandler returns the mouse handler for this primitive.
 func (c *Checkbox) MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) {
 	return c.WrapMouseHandler(func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) {
 		if c.disabled {
 			return false, nil
 		}
 
 		x, y := event.Position()
 		_, rectY, _, _ := c.GetInnerRect()
 		if !c.InRect(x, y) {
 			return false, nil
 		}
 
 		// Process mouse event.
 		if y == rectY {
 			if action == MouseLeftDown {
 				setFocus(c)
 				consumed = true
 			} else if action == MouseLeftClick {
 				c.checked = !c.checked
 				if c.changed != nil {
 					c.changed(c.checked)
 				}
 				consumed = true
 			}
 		}
 
 		return
 	})
 }