ui/tabbedview.go

package ui

import (
	"sync"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/container"
)

type TabbedView struct {
	*BaseView

	// The array of child views
	tabViews []View

	// The current active view
	currentTabView View

	// The tabs
	tabs *container.AppTabs

	// The location of teh tabs in the view
	tabLocation container.TabLocation

	mu sync.Mutex
}

// NewTabbedView creates a new tabbed view
func NewTabbedView(
	controller Controller,
	tabLocation container.TabLocation,
	tabview ...View,
) *TabbedView {
	v := new(TabbedView)
	v.BaseView = NewBaseView(v, controller)
	v.tabViews = tabview
	v.tabLocation = tabLocation
	return v
}

func (v *TabbedView) Initialize() fyne.CanvasObject {
	v.buildUI()
	return v.BaseView.Initialize()
}

func (v *TabbedView) OnShow() {
	v.BaseView.OnShow()
	if v.currentTabView != nil {
		v.currentTabView.OnShow()
	}
}

func (v *TabbedView) OnHide() {
	if v.currentTabView != nil {
		v.currentTabView.OnHide()
	}
	v.BaseView.OnHide()
}

func (v *TabbedView) Refresh() {
	if v.currentTabView != nil {
		v.currentTabView.Refresh()
	}
	v.BaseView.Refresh()
}

func (v *TabbedView) Append(tabview ...View) {
	v.mu.Lock()
	defer v.mu.Unlock()

	v.tabViews = append(v.tabViews, tabview...)
	for _, tv := range tabview {
		v.tabs.Append(container.NewTabItem(
			tv.Title(), tv.Initialize()))
	}
}

func (v *TabbedView) RemoveActive() {
	currIdx := v.tabs.SelectedIndex()
	v.Remove(currIdx)
}

func (v *TabbedView) Remove(idx int) {
	if idx < 0 || idx >= len(v.tabViews) {
		return
	}

	curIdx := v.tabs.SelectedIndex()
	isCurrent := (curIdx == idx) && (v.currentTabView != nil)

	v.mu.Lock()
	defer v.mu.Unlock()

	if isCurrent {
		v.currentTabView.OnHide()
		v.currentTabView = nil
	}
	v.tabViews = append(v.tabViews[0:curIdx], v.tabViews[curIdx+1:]...)
	v.tabs.RemoveIndex(idx)

	if isCurrent {
		if idx > 0 {
			idx = idx - 1
		}
		if idx < len(v.tabViews) {
			v.tabs.SelectIndex(curIdx)
		}
	}
}

func (v *TabbedView) NumTabs() int {
	return len(v.tabViews)
}

func (v *TabbedView) TabIndex(view View) int {
	for idx, tv := range v.tabViews {
		if tv.Equals(view) {
			return idx
		}
	}
	return -1
}

func (v *TabbedView) SelectTabIndex(index int) {
	v.tabs.SelectIndex(index)
}

func (v *TabbedView) SelectTab(view View) {
	v.SelectTabIndex(v.TabIndex(view))
}

func (v *TabbedView) buildUI() {
	v.tabs = container.NewAppTabs()
	v.tabs.SetTabLocation(v.tabLocation)
	v.tabs.OnSelected = func(tab *container.TabItem) {
		LogWindowEventMessage(
			v, OnTabSelected,
			"Selected tab: %s",
			tab.Text,
		)

		go func() {
			v.mu.Lock()
			defer v.mu.Unlock()

			idx := v.tabs.SelectedIndex()
			if idx < 0 || idx >= len(v.tabViews) {
				return
			}

			v.currentTabView = v.tabViews[idx]
			v.currentTabView.OnShow()
		}()
	}
	v.tabs.OnUnselected = func(tab *container.TabItem) {
		LogWindowEventMessage(
			v, OnTabUnselected,
			"Unselected tab: %s",
			tab.Text,
		)

		go func() {
			v.mu.Lock()
			defer v.mu.Unlock()

			idx := v.tabs.SelectedIndex()
			if idx < 0 || idx >= len(v.tabViews) {
				return
			}

			if v.currentTabView != nil && v.currentTabView.Equals(v.tabViews[idx]) {
				v.currentTabView.OnHide()
				v.currentTabView = nil
			}
		}()
	}

	for _, tv := range v.tabViews {
		v.tabs.Append(container.NewTabItem(tv.Title(), tv.Initialize()))
	}
	if len(v.tabViews) > 0 {
		v.currentTabView = v.tabViews[0]
	}
	v.CanvasObject = v.tabs
}