andlabs-ui/listbox.go

144 lines
3.4 KiB
Go

// 14 february 2014
package ui
import (
"fmt"
"sync"
)
// A Listbox is a vertical list of items, of which either at most one or any number of items can be selected at any given time.
// On creation, no item is selected.
type Listbox struct {
// TODO Select event
lock sync.Mutex
created bool
sysData *sysData
initItems []string
}
// NewCombobox makes a new combobox with the given items. If multiple is true, the listbox allows multiple selection.
func NewListbox(multiple bool, items ...string) (l *Listbox) {
l = &Listbox{
sysData: mksysdata(c_listbox),
initItems: items,
}
l.sysData.alternate = multiple
return l
}
// Append adds items to the end of the Listbox's list.
func (l *Listbox) Append(what ...string) (err error) {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
for i, s := range what {
err := l.sysData.append(s)
if err != nil {
return fmt.Errorf("error adding element %d in Listbox.Append() (%q): %v", i, s, err)
}
}
return nil
}
l.initItems = append(l.initItems, what...)
return nil
}
// InsertBefore inserts a new item in the Listbox before the item at the given position.
// (TODO action on invalid index)
func (l *Listbox) InsertBefore(what string, before int) (err error) {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
return l.sysData.insertBefore(what, before)
}
m := make([]string, 0, len(l.initItems) + 1)
m = append(m, l.initItems[:before]...)
m = append(m, what)
l.initItems = append(m, l.initItems[before:]...)
return nil
}
// Delete removes the given item from the Listbox.
// (TODO action on invalid index)
func (l *Listbox) Delete(index int) error {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
return l.sysData.delete(index)
}
l.initItems = append(l.initItems[:index], l.initItems[index + 1:]...)
return nil
}
// Selection returns a list of strings currently selected in the Listbox, or an empty list if none have been selected. This list will have at most one item on a single-selection Listbox.
func (l *Listbox) Selection() []string {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
return l.sysData.selectedTexts()
}
return nil
}
// SelectedIndices returns a list of the currently selected indexes in the Listbox, or an empty list if none have been selected. This list will have at most one item on a single-selection Listbox.
func (l *Listbox) SelectedIndices() []int {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
return l.sysData.selectedIndices()
}
return nil
}
// Len returns the number of items in the Listbox.
//
// On platforms for which this function may return an error, it panics if one is returned.
func (l *Listbox) Len() int {
l.lock.Lock()
defer l.lock.Unlock()
if l.created {
return l.sysData.len()
}
return len(l.initItems)
}
func (l *Listbox) make(window *sysData) (err error) {
l.lock.Lock()
defer l.lock.Unlock()
err = l.sysData.make("", window)
if err != nil {
return err
}
for _, s := range l.initItems {
err = l.sysData.append(s)
if err != nil {
return err
}
}
l.created = true
return nil
}
func (l *Listbox) setRect(x int, y int, width int, height int, winheight int) error {
l.lock.Lock()
defer l.lock.Unlock()
return l.sysData.setRect(x, y, width, height, winheight)
}
func (l *Listbox) preferredSize() (width int, height int, err error) {
l.lock.Lock()
defer l.lock.Unlock()
width, height = l.sysData.preferredSize()
return
}