package tview import ( "github.com/gdamore/tcell" ) // page represents one page of a Pages object. type page struct { Name string // The page's name. Item Primitive // The page's primitive. Resize bool // Whether or not to resize the page when it is drawn. Visible bool // Whether or not this page is visible. } // Pages is a container for other primitives often used as the application's // root primitive. It allows to easily switch the visibility of the contained // primitives. // // See https://github.com/rivo/tview/wiki/Pages for an example. type Pages struct { *Box // The contained pages. pages []*page // We keep a reference to the function which allows us to set the focus to // a newly visible page. setFocus func(p Primitive) // An optional handler which is called whenever the visibility or the order of // pages changes. changed func() } // NewPages returns a new Pages object. func NewPages() *Pages { p := &Pages{ Box: NewBox(), } p.focus = p return p } // SetChangedFunc sets a handler which is called whenever the visibility or the // order of any visible pages changes. This can be used to redraw the pages. func (p *Pages) SetChangedFunc(handler func()) *Pages { p.changed = handler return p } // GetPageCount returns the number of pages currently stored in this object. func (p *Pages) GetPageCount() int { return len(p.pages) } // AddPage adds a new page with the given name and primitive. If there was // previously a page with the same name, it is overwritten. Leaving the name // empty may cause conflicts in other functions so always specify a non-empty // name. // // Visible pages will be drawn in the order they were added (unless that order // was changed in one of the other functions). If "resize" is set to true, the // primitive will be set to the size available to the Pages primitive whenever // the pages are drawn. func (p *Pages) AddPage(name string, item Primitive, resize, visible bool) *Pages { hasFocus := p.HasFocus() for index, pg := range p.pages { if pg.Name == name { p.pages = append(p.pages[:index], p.pages[index+1:]...) break } } p.pages = append(p.pages, &page{Item: item, Name: name, Resize: resize, Visible: visible}) if p.changed != nil { p.changed() } if hasFocus { p.Focus(p.setFocus) } return p } // AddAndSwitchToPage calls AddPage(), then SwitchToPage() on that newly added // page. func (p *Pages) AddAndSwitchToPage(name string, item Primitive, resize bool) *Pages { p.AddPage(name, item, resize, true) p.SwitchToPage(name) return p } // RemovePage removes the page with the given name. If that page was the only // visible page, visibility is assigned to the last page. func (p *Pages) RemovePage(name string) *Pages { var isVisible bool hasFocus := p.HasFocus() for index, page := range p.pages { if page.Name == name { isVisible = page.Visible p.pages = append(p.pages[:index], p.pages[index+1:]...) if page.Visible && p.changed != nil { p.changed() } break } } if isVisible { for index, page := range p.pages { if index < len(p.pages)-1 { if page.Visible { break // There is a remaining visible page. } } else { page.Visible = true // We need at least one visible page. } } } if hasFocus { p.Focus(p.setFocus) } return p } // HasPage returns true if a page with the given name exists in this object. func (p *Pages) HasPage(name string) bool { for _, page := range p.pages { if page.Name == name { return true } } return false } // ShowPage sets a page's visibility to "true" (in addition to any other pages // which are already visible). func (p *Pages) ShowPage(name string) *Pages { for _, page := range p.pages { if page.Name == name { page.Visible = true if p.changed != nil { p.changed() } break } } if p.HasFocus() { p.Focus(p.setFocus) } return p } // HidePage sets a page's visibility to "false". func (p *Pages) HidePage(name string) *Pages { for _, page := range p.pages { if page.Name == name { page.Visible = false if p.changed != nil { p.changed() } break } } if p.HasFocus() { p.Focus(p.setFocus) } return p } // SwitchToPage sets a page's visibility to "true" and all other pages' // visibility to "false". func (p *Pages) SwitchToPage(name string) *Pages { for _, page := range p.pages { if page.Name == name { page.Visible = true } else { page.Visible = false } } if p.changed != nil { p.changed() } if p.HasFocus() { p.Focus(p.setFocus) } return p } // SendToFront changes the order of the pages such that the page with the given // name comes last, causing it to be drawn last with the next update (if // visible). func (p *Pages) SendToFront(name string) *Pages { for index, page := range p.pages { if page.Name == name { if index < len(p.pages)-1 { p.pages = append(append(p.pages[:index], p.pages[index+1:]...), page) } if page.Visible && p.changed != nil { p.changed() } break } } if p.HasFocus() { p.Focus(p.setFocus) } return p } // SendToBack changes the order of the pages such that the page with the given // name comes first, causing it to be drawn first with the next update (if // visible). func (p *Pages) SendToBack(name string) *Pages { for index, pg := range p.pages { if pg.Name == name { if index > 0 { p.pages = append(append([]*page{pg}, p.pages[:index]...), p.pages[index+1:]...) } if pg.Visible && p.changed != nil { p.changed() } break } } if p.HasFocus() { p.Focus(p.setFocus) } return p } // GetFrontPage returns the front-most visible page. If there are no visible // pages, ("", nil) is returned. func (p *Pages) GetFrontPage() (name string, item Primitive) { for index := len(p.pages) - 1; index >= 0; index-- { if p.pages[index].Visible { return p.pages[index].Name, p.pages[index].Item } } return } // HasFocus returns whether or not this primitive has focus. func (p *Pages) HasFocus() bool { for _, page := range p.pages { if page.Item.GetFocusable().HasFocus() { return true } } return false } // Focus is called by the application when the primitive receives focus. func (p *Pages) Focus(delegate func(p Primitive)) { if delegate == nil { return // We cannot delegate so we cannot focus. } p.setFocus = delegate var topItem Primitive for _, page := range p.pages { if page.Visible { topItem = page.Item } } if topItem != nil { delegate(topItem) } } // Draw draws this primitive onto the screen. func (p *Pages) Draw(screen tcell.Screen) { p.Box.Draw(screen) for _, page := range p.pages { if !page.Visible { continue } if page.Resize { x, y, width, height := p.GetInnerRect() page.Item.SetRect(x, y, width, height) } page.Item.Draw(screen) } } func (p *Pages) GetChildren() []Primitive { var children []Primitive for _, page := range p.pages { // Considering invisible pages as not children. // Even though we track all the pages, not all are "children" currently. if page.Visible { children = append(children, page.Item) } } return children }