src/Tizen.NUI.Components/Controls/Navigation/Navigator.cs

   1 /*
   2  * Copyright(c) 2021 Samsung Electronics Co., Ltd.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  *
  16  */
  17
  18 using System;
  19 using System.Collections.Generic;
  20 using System.ComponentModel;
  21 using Tizen.NUI.BaseComponents;
  22 using Tizen.NUI.Binding;
  23
  24 namespace Tizen.NUI.Components
  25 {
  26     /// <summary>
  27     /// PoppedEventArgs is a class to record <see cref="Navigator.Popped"/> event arguments which will be sent to user.
  28     /// </summary>
  29     /// <since_tizen> 9 </since_tizen>
  30     public class PoppedEventArgs : EventArgs
  31     {
  32         /// <summary>
  33         /// Page popped by Navigator.
  34         /// </summary>
  35         /// <since_tizen> 9 </since_tizen>
  36         public Page Page { get; internal set; }
  37     }
  38
  39     /// <summary>
  40     /// The Navigator is a class which navigates pages with stack methods such as Push and Pop.
  41     /// </summary>
  42     /// <remarks>
  43     /// With Transition class, Navigator supports smooth transition of View pair between two Pages
  44     /// by using <see cref="PushWithTransition(Page)"/> and <see cref="PopWithTransition()"/> methods.
  45     /// If current top Page and next top Page have <see cref="View"/>s those have same TransitionTag,
  46     /// Navigator creates smooth transition motion for them.
  47     /// Navigator.Transition property can be used to set properties of the Transition such as TimePeriod and AlphaFunction.
  48     /// When all transitions are finished, Navigator calls a callback methods those connected on the "TransitionFinished" event.
  49     /// </remarks>
  50     /// <example>
  51     /// <code>
  52     /// Navigator navigator = new Navigator()
  53     /// {
  54     ///     TimePeriod = new TimePeriod(500),
  55     ///     AlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.EaseInOutSine)
  56     /// };
  57     ///
  58     /// View view = new View()
  59     /// {
  60     ///     TransitionOptions = new TransitionOptions()
  61     ///     {
  62     ///         /* Set properties for the transition of this View */
  63     ///     }
  64     /// };
  65     ///
  66     /// ContentPage newPage = new ContentPage()
  67     /// {
  68     ///     Content = view,
  69     /// };
  70     ///
  71     /// Navigator.PushWithTransition(newPage);
  72     /// </code>
  73     /// </example>
  74     /// <since_tizen> 9 </since_tizen>
  75     public class Navigator : Control
  76     {
  77         /// <summary>
  78         /// TransitionProperty
  79         /// </summary>
  80         [EditorBrowsable(EditorBrowsableState.Never)]
  81         public static readonly BindableProperty TransitionProperty = BindableProperty.Create(nameof(Transition), typeof(Transition), typeof(Navigator), null, propertyChanged: (bindable, oldValue, newValue) =>
  82         {
  83             var instance = (Navigator)bindable;
  84             if (newValue != null)
  85             {
  86                 instance.InternalTransition = newValue as Transition;
  87             }
  88         },
  89         defaultValueCreator: (bindable) =>
  90         {
  91             var instance = (Navigator)bindable;
  92             return instance.InternalTransition;
  93         });
  94
  95         /// <summary>
  96         /// EnableBackNavigationProperty
  97         /// </summary>
  98         [EditorBrowsable(EditorBrowsableState.Never)]
  99         public static readonly BindableProperty EnableBackNavigationProperty = BindableProperty.Create(nameof(EnableBackNavigation), typeof(bool), typeof(Navigator), default(bool), propertyChanged: (bindable, oldValue, newValue) =>
 100         {
 101             var instance = (Navigator)bindable;
 102             if (newValue != null)
 103             {
 104                 instance.InternalEnableBackNavigation = (bool)newValue;
 105             }
 106         },
 107         defaultValueCreator: (bindable) =>
 108         {
 109             var instance = (Navigator)bindable;
 110             return instance.InternalEnableBackNavigation;
 111         });
 112
 113         private const int DefaultTransitionDuration = 300;
 114
 115         //This will be replaced with view transition class instance.
 116         private Animation curAnimation = null;
 117
 118         //This will be replaced with view transition class instance.
 119         private Animation newAnimation = null;
 120
 121         private TransitionSet transitionSet = null;
 122
 123         private Transition transition = new Transition()
 124         {
 125             TimePeriod = new TimePeriod(DefaultTransitionDuration),
 126             AlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.Default),
 127         };
 128
 129         private bool transitionFinished = true;
 130
 131         //TODO: Needs to consider how to remove disposed window from dictionary.
 132         //Two dictionaries are required to remove disposed navigator from dictionary.
 133         private static Dictionary<Window, Navigator> windowNavigator = new Dictionary<Window, Navigator>();
 134         private static Dictionary<Navigator, Window> navigatorWindow = new Dictionary<Navigator, Window>();
 135
 136         private List<Page> navigationPages = new List<Page>();
 137
 138         private bool enableBackNavigation = true;
 139
 140         private Window parentWindow;
 141
 142         private void OnWindowKeyEvent(object sender, Window.KeyEventArgs e)
 143         {
 144             if (!EnableBackNavigation)
 145             {
 146                 return;
 147             }
 148
 149             if ((e.Key.State == Key.StateType.Up) && ((e.Key.KeyPressedName == "Escape") || (e.Key.KeyPressedName == "BackSpace") || (e.Key.KeyPressedName == "XF86Back")))
 150             {
 151                 OnBackNavigation(new BackNavigationEventArgs());
 152             }
 153         }
 154
 155         private void OnAddedToWindow(object sender, EventArgs e)
 156         {
 157             parentWindow = Window.Get(this);
 158             parentWindow.KeyEvent += OnWindowKeyEvent;
 159         }
 160
 161         private void OnRemovedFromWindow(object sender, EventArgs e)
 162         {
 163             parentWindow.KeyEvent -= OnWindowKeyEvent;
 164             parentWindow = null;
 165         }
 166
 167         private void Initialize()
 168         {
 169             Layout = new AbsoluteLayout();
 170
 171             AddedToWindow += OnAddedToWindow;
 172             RemovedFromWindow += OnRemovedFromWindow;
 173         }
 174
 175         /// <summary>
 176         /// Creates a new instance of a Navigator.
 177         /// </summary>
 178         /// <since_tizen> 9 </since_tizen>
 179         public Navigator() : base()
 180         {
 181             Initialize();
 182         }
 183
 184         /// <summary>
 185         /// Creates a new instance of Navigator with style.
 186         /// </summary>
 187         /// <param name="style">Creates Navigator by special style defined in UX.</param>
 188         [EditorBrowsable(EditorBrowsableState.Never)]
 189         public Navigator(string style) : base(style)
 190         {
 191             Initialize();
 192         }
 193
 194         /// <summary>
 195         /// Creates a new instance of a Navigator with style.
 196         /// </summary>
 197         /// <param name="style">A style applied to the newly created Navigator.</param>
 198         [EditorBrowsable(EditorBrowsableState.Never)]
 199         public Navigator(ControlStyle style) : base(style)
 200         {
 201             Initialize();
 202         }
 203
 204         /// <inheritdoc/>
 205         [EditorBrowsable(EditorBrowsableState.Never)]
 206         public override void OnInitialize()
 207         {
 208             base.OnInitialize();
 209
 210             AccessibilityRole = Role.PageTabList;
 211         }
 212
 213         /// <summary>
 214         /// An event fired when Transition has been finished.
 215         /// </summary>
 216         /// <since_tizen> 9 </since_tizen>
 217         public event EventHandler<EventArgs> TransitionFinished;
 218
 219         /// <summary>
 220         /// An event fired when Pop of a page has been finished.
 221         /// </summary>
 222         /// <remarks>
 223         /// When you free resources in the Popped event handler, please make sure if the popped page is the page you find.
 224         /// </remarks>
 225         /// <since_tizen> 9 </since_tizen>
 226         public event EventHandler<PoppedEventArgs> Popped;
 227
 228         /// <summary>
 229         /// Returns the count of pages in Navigator.
 230         /// </summary>
 231         /// <since_tizen> 9 </since_tizen>
 232         public int PageCount => navigationPages.Count;
 233
 234         /// <summary>
 235         /// Transition properties for the transition of View pair having same transition tag.
 236         /// </summary>
 237         /// <since_tizen> 9 </since_tizen>
 238         public Transition Transition
 239         {
 240             get
 241             {
 242                 return GetValue(TransitionProperty) as Transition;
 243             }
 244             set
 245             {
 246                 SetValue(TransitionProperty, value);
 247                 NotifyPropertyChanged();
 248             }
 249         }
 250         private Transition InternalTransition
 251         {
 252             set
 253             {
 254                 transition = value;
 255             }
 256             get
 257             {
 258                 return transition;
 259             }
 260         }
 261
 262         /// <summary>
 263         /// Pushes a page to Navigator.
 264         /// If the page is already in Navigator, then it is not pushed.
 265         /// </summary>
 266         /// <param name="page">The page to push to Navigator.</param>
 267         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 268         /// <since_tizen> 9 </since_tizen>
 269         public void PushWithTransition(Page page)
 270         {
 271             if (!transitionFinished)
 272             {
 273                 Tizen.Log.Error("NUI", "Transition is still not finished.\n");
 274                 return;
 275             }
 276
 277             if (page == null)
 278             {
 279                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 280             }
 281
 282             //Duplicate page is not pushed.
 283             if (navigationPages.Contains(page)) return;
 284
 285             var topPage = Peek();
 286
 287             if (!topPage)
 288             {
 289                 Insert(0, page);
 290                 return;
 291             }
 292
 293             navigationPages.Add(page);
 294             Add(page);
 295             page.Navigator = this;
 296
 297             //Invoke Page events
 298             page.InvokeAppearing();
 299             topPage.InvokeDisappearing();
 300             topPage.SaveKeyFocus();
 301
 302             transitionSet = CreateTransitions(topPage, page, true);
 303             transitionSet.Finished += (object sender, EventArgs e) =>
 304             {
 305                 if (page is DialogPage == false)
 306                 {
 307                     topPage.SetVisible(false);
 308                 }
 309
 310                 // Need to update Content of the new page
 311                 ShowContentOfPage(page);
 312
 313                 //Invoke Page events
 314                 page.InvokeAppeared();
 315                 page.RestoreKeyFocus();
 316
 317                 topPage.InvokeDisappeared();
 318                 NotifyAccessibilityStatesChangeOfPages(topPage, page);
 319             };
 320             transitionFinished = false;
 321         }
 322
 323         /// <summary>
 324         /// Pops the top page from Navigator.
 325         /// </summary>
 326         /// <returns>The popped page.</returns>
 327         /// <exception cref="InvalidOperationException">Thrown when there is no page in Navigator.</exception>
 328         /// <since_tizen> 9 </since_tizen>
 329         public Page PopWithTransition()
 330         {
 331             if (!transitionFinished)
 332             {
 333                 Tizen.Log.Error("NUI", "Transition is still not finished.\n");
 334                 return null;
 335             }
 336
 337             if (navigationPages.Count == 0)
 338             {
 339                 throw new InvalidOperationException("There is no page in Navigator.");
 340             }
 341
 342             var topPage = Peek();
 343
 344             if (navigationPages.Count == 1)
 345             {
 346                 Remove(topPage);
 347
 348                 //Invoke Popped event
 349                 Popped?.Invoke(this, new PoppedEventArgs() { Page = topPage });
 350
 351                 return topPage;
 352             }
 353             var newTopPage = navigationPages[navigationPages.Count - 2];
 354
 355             //Invoke Page events
 356             newTopPage.InvokeAppearing();
 357             topPage.InvokeDisappearing();
 358             topPage.SaveKeyFocus();
 359
 360             transitionSet = CreateTransitions(topPage, newTopPage, false);
 361             transitionSet.Finished += (object sender, EventArgs e) =>
 362             {
 363                 Remove(topPage);
 364                 topPage.SetVisible(true);
 365
 366                 // Need to update Content of the new page
 367                 ShowContentOfPage(newTopPage);
 368
 369                 //Invoke Page events
 370                 newTopPage.InvokeAppeared();
 371                 newTopPage.RestoreKeyFocus();
 372
 373                 topPage.InvokeDisappeared();
 374
 375                 //Invoke Popped event
 376                 Popped?.Invoke(this, new PoppedEventArgs() { Page = topPage });
 377             };
 378             transitionFinished = false;
 379
 380             return topPage;
 381         }
 382
 383         /// <summary>
 384         /// Pushes a page to Navigator.
 385         /// If the page is already in Navigator, then it is not pushed.
 386         /// </summary>
 387         /// <param name="page">The page to push to Navigator.</param>
 388         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 389         /// <since_tizen> 9 </since_tizen>
 390         public void Push(Page page)
 391         {
 392             if (!transitionFinished)
 393             {
 394                 Tizen.Log.Error("NUI", "Transition is still not finished.\n");
 395                 return;
 396             }
 397
 398             if (page == null)
 399             {
 400                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 401             }
 402
 403             //Duplicate page is not pushed.
 404             if (navigationPages.Contains(page)) return;
 405
 406             var curTop = Peek();
 407
 408             if (!curTop)
 409             {
 410                 Insert(0, page);
 411                 return;
 412             }
 413
 414             navigationPages.Add(page);
 415             Add(page);
 416             page.Navigator = this;
 417
 418             //Invoke Page events
 419             page.InvokeAppearing();
 420             curTop.InvokeDisappearing();
 421
 422             curTop.SaveKeyFocus();
 423
 424             //TODO: The following transition codes will be replaced with view transition.
 425             InitializeAnimation();
 426
 427             if (page is DialogPage == false)
 428             {
 429                 curAnimation = new Animation(DefaultTransitionDuration);
 430                 curAnimation.AnimateTo(curTop, "PositionX", 0.0f, 0, DefaultTransitionDuration);
 431                 curAnimation.EndAction = Animation.EndActions.StopFinal;
 432                 curAnimation.Finished += (object sender, EventArgs args) =>
 433                 {
 434                     curTop.SetVisible(false);
 435
 436                     //Invoke Page events
 437                     curTop.InvokeDisappeared();
 438                 };
 439                 curAnimation.Play();
 440
 441                 page.PositionX = SizeWidth;
 442                 page.SetVisible(true);
 443                 // Set Content visible because it was hidden by HideContentOfPage.
 444                 (page as ContentPage)?.Content?.SetVisible(true);
 445
 446                 newAnimation = new Animation(DefaultTransitionDuration);
 447                 newAnimation.AnimateTo(page, "PositionX", 0.0f, 0, DefaultTransitionDuration);
 448                 newAnimation.EndAction = Animation.EndActions.StopFinal;
 449                 newAnimation.Finished += (object sender, EventArgs e) =>
 450                 {
 451                     // Need to update Content of the new page
 452                     ShowContentOfPage(page);
 453
 454                     //Invoke Page events
 455                     page.InvokeAppeared();
 456                     NotifyAccessibilityStatesChangeOfPages(curTop, page);
 457
 458                     page.RestoreKeyFocus();
 459                 };
 460                 newAnimation.Play();
 461             }
 462             else
 463             {
 464                 ShowContentOfPage(page);
 465                 page.RestoreKeyFocus();
 466             }
 467         }
 468
 469         /// <summary>
 470         /// Pops the top page from Navigator.
 471         /// </summary>
 472         /// <returns>The popped page.</returns>
 473         /// <exception cref="InvalidOperationException">Thrown when there is no page in Navigator.</exception>
 474         /// <since_tizen> 9 </since_tizen>
 475         public Page Pop()
 476         {
 477             if (!transitionFinished)
 478             {
 479                 Tizen.Log.Error("NUI", "Transition is still not finished.\n");
 480                 return null;
 481             }
 482
 483             if (navigationPages.Count == 0)
 484             {
 485                 throw new InvalidOperationException("There is no page in Navigator.");
 486             }
 487
 488             var curTop = Peek();
 489
 490             if (navigationPages.Count == 1)
 491             {
 492                 Remove(curTop);
 493
 494                 //Invoke Popped event
 495                 Popped?.Invoke(this, new PoppedEventArgs() { Page = curTop });
 496
 497                 return curTop;
 498             }
 499
 500             var newTop = navigationPages[navigationPages.Count - 2];
 501
 502             //Invoke Page events
 503             newTop.InvokeAppearing();
 504             curTop.InvokeDisappearing();
 505             curTop.SaveKeyFocus();
 506
 507             //TODO: The following transition codes will be replaced with view transition.
 508             InitializeAnimation();
 509
 510             if (curTop is DialogPage == false)
 511             {
 512                 curAnimation = new Animation(DefaultTransitionDuration);
 513                 curAnimation.AnimateTo(curTop, "PositionX", SizeWidth, 0, DefaultTransitionDuration);
 514                 curAnimation.EndAction = Animation.EndActions.StopFinal;
 515                 curAnimation.Finished += (object sender, EventArgs e) =>
 516                 {
 517                     //Removes the current top page after transition is finished.
 518                     Remove(curTop);
 519
 520                     curTop.PositionX = 0.0f;
 521
 522                     //Invoke Page events
 523                     curTop.InvokeDisappeared();
 524
 525                     //Invoke Popped event
 526                     Popped?.Invoke(this, new PoppedEventArgs() { Page = curTop });
 527                 };
 528                 curAnimation.Play();
 529
 530                 newTop.SetVisible(true);
 531                 // Set Content visible because it was hidden by HideContentOfPage.
 532                 (newTop as ContentPage)?.Content?.SetVisible(true);
 533
 534                 newAnimation = new Animation(DefaultTransitionDuration);
 535                 newAnimation.AnimateTo(newTop, "PositionX", 0.0f, 0, DefaultTransitionDuration);
 536                 newAnimation.EndAction = Animation.EndActions.StopFinal;
 537                 newAnimation.Finished += (object sender, EventArgs e) =>
 538                 {
 539                     // Need to update Content of the new page
 540                     ShowContentOfPage(newTop);
 541
 542                     //Invoke Page events
 543                     newTop.InvokeAppeared();
 544
 545                     newTop.RestoreKeyFocus();
 546                 };
 547                 newAnimation.Play();
 548             }
 549             else
 550             {
 551                 Remove(curTop);
 552                 newTop.RestoreKeyFocus();
 553             }
 554
 555             return curTop;
 556         }
 557
 558         /// <summary>
 559         /// Returns the page of the given index in Navigator.
 560         /// The indices of pages in Navigator are basically the order of pushing or inserting to Navigator.
 561         /// So a page's index in Navigator can be changed whenever push/insert or pop/remove occurs.
 562         /// </summary>
 563         /// <param name="index">The index of a page in Navigator.</param>
 564         /// <returns>The page of the given index in Navigator.</returns>
 565         /// <exception cref="ArgumentOutOfRangeException">Thrown when the argument index is less than 0, or greater than the number of pages.</exception>
 566         public Page GetPage(int index)
 567         {
 568             if ((index < 0) || (index > navigationPages.Count))
 569             {
 570                 throw new ArgumentOutOfRangeException(nameof(index), "index should be greater than or equal to 0, and less than or equal to the number of pages.");
 571             }
 572
 573             return navigationPages[index];
 574         }
 575
 576         /// <summary>
 577         /// Returns the current index of the given page in Navigator.
 578         /// The indices of pages in Navigator are basically the order of pushing or inserting to Navigator.
 579         /// So a page's index in Navigator can be changed whenever push/insert or pop/remove occurs.
 580         /// </summary>
 581         /// <param name="page">The page in Navigator.</param>
 582         /// <returns>The index of the given page in Navigator. If the given page is not in the Navigator, then -1 is returned.</returns>
 583         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 584         /// <since_tizen> 9 </since_tizen>
 585         public int IndexOf(Page page)
 586         {
 587             if (page == null)
 588             {
 589                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 590             }
 591
 592             for (int i = 0; i < navigationPages.Count; i++)
 593             {
 594                 if (navigationPages[i] == page)
 595                 {
 596                     return i;
 597                 }
 598             }
 599
 600             return -1;
 601         }
 602
 603         /// <summary>
 604         /// Inserts a page at the specified index of Navigator.
 605         /// The indices of pages in Navigator are basically the order of pushing or inserting to Navigator.
 606         /// So a page's index in Navigator can be changed whenever push/insert or pop/remove occurs.
 607         /// To find the current index of a page in Navigator, please use IndexOf(page).
 608         /// If the page is already in Navigator, then it is not inserted.
 609         /// </summary>
 610         /// <param name="index">The index of a page in Navigator where the page will be inserted.</param>
 611         /// <param name="page">The page to insert to Navigator.</param>
 612         /// <exception cref="ArgumentOutOfRangeException">Thrown when the argument index is less than 0, or greater than the number of pages.</exception>
 613         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 614         /// <since_tizen> 9 </since_tizen>
 615         public void Insert(int index, Page page)
 616         {
 617             if ((index < 0) || (index > navigationPages.Count))
 618             {
 619                 throw new ArgumentOutOfRangeException(nameof(index), "index should be greater than or equal to 0, and less than or equal to the number of pages.");
 620             }
 621
 622             if (page == null)
 623             {
 624                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 625             }
 626
 627             //Duplicate page is not pushed.
 628             if (navigationPages.Contains(page)) return;
 629
 630             //TODO: The following transition codes will be replaced with view transition.
 631             InitializeAnimation();
 632
 633             ShowContentOfPage(page);
 634
 635             if (index == PageCount)
 636             {
 637                 page.SetVisible(true);
 638             }
 639             else
 640             {
 641                 page.SetVisible(false);
 642             }
 643
 644             navigationPages.Insert(index, page);
 645             Add(page);
 646             page.SiblingOrder = index;
 647             page.Navigator = this;
 648             if (index == PageCount - 1)
 649             {
 650                 if (PageCount > 1)
 651                 {
 652                     NotifyAccessibilityStatesChangeOfPages(navigationPages[PageCount - 2], page);
 653                 }
 654                 else
 655                 {
 656                     NotifyAccessibilityStatesChangeOfPages(null, page);
 657                 }
 658             }
 659         }
 660
 661         /// <summary>
 662         /// Inserts a page to Navigator before an existing page.
 663         /// If the page is already in Navigator, then it is not inserted.
 664         /// </summary>
 665         /// <param name="before">The existing page, before which a page will be inserted.</param>
 666         /// <param name="page">The page to insert to Navigator.</param>
 667         /// <exception cref="ArgumentNullException">Thrown when the argument before is null.</exception>
 668         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 669         /// <exception cref="ArgumentException">Thrown when the argument before does not exist in Navigator.</exception>
 670         /// <since_tizen> 9 </since_tizen>
 671         public void InsertBefore(Page before, Page page)
 672         {
 673             if (before == null)
 674             {
 675                 throw new ArgumentNullException(nameof(before), "before should not be null.");
 676             }
 677
 678             if (page == null)
 679             {
 680                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 681             }
 682
 683             //Find the index of before page.
 684             int beforeIndex = navigationPages.FindIndex(x => x == before);
 685
 686             //before does not exist in Navigator.
 687             if (beforeIndex == -1)
 688             {
 689                 throw new ArgumentException("before does not exist in Navigator.", nameof(before));
 690             }
 691
 692             Insert(beforeIndex, page);
 693         }
 694
 695         /// <summary>
 696         /// Removes a page from Navigator.
 697         /// </summary>
 698         /// <param name="page">The page to remove from Navigator.</param>
 699         /// <exception cref="ArgumentNullException">Thrown when the argument page is null.</exception>
 700         /// <since_tizen> 9 </since_tizen>
 701         public void Remove(Page page)
 702         {
 703             if (page == null)
 704             {
 705                 throw new ArgumentNullException(nameof(page), "page should not be null.");
 706             }
 707
 708             //TODO: The following transition codes will be replaced with view transition.
 709             InitializeAnimation();
 710
 711             HideContentOfPage(page);
 712
 713             if (page == Peek())
 714             {
 715                 if (PageCount >= 2)
 716                 {
 717                     navigationPages[PageCount - 2].SetVisible(true);
 718                     NotifyAccessibilityStatesChangeOfPages(page, navigationPages[PageCount - 2]);
 719                 }
 720                 else if (PageCount == 1)
 721                 {
 722                     NotifyAccessibilityStatesChangeOfPages(page, null);
 723                 }
 724             }
 725             page.Navigator = null;
 726             navigationPages.Remove(page);
 727             base.Remove(page);
 728         }
 729
 730         /// <summary>
 731         /// Removes a page at the specified index of Navigator.
 732         /// The indices of pages in Navigator are basically the order of pushing or inserting to Navigator.
 733         /// So a page's index in Navigator can be changed whenever push/insert or pop/remove occurs.
 734         /// To find the current index of a page in Navigator, please use IndexOf(page).
 735         /// </summary>
 736         /// <param name="index">The index of a page in Navigator where the page will be removed.</param>
 737         /// <exception cref="ArgumentOutOfRangeException">Thrown when the index is less than 0, or greater than or equal to the number of pages.</exception>
 738         /// <since_tizen> 9 </since_tizen>
 739         public void RemoveAt(int index)
 740         {
 741             if ((index < 0) || (index >= navigationPages.Count))
 742             {
 743                 throw new ArgumentOutOfRangeException(nameof(index), "index should be greater than or equal to 0, and less than the number of pages.");
 744             }
 745
 746             Remove(navigationPages[index]);
 747         }
 748
 749         /// <summary>
 750         /// Returns the page at the top of Navigator.
 751         /// </summary>
 752         /// <returns>The page at the top of Navigator.</returns>
 753         /// <since_tizen> 9 </since_tizen>
 754         public Page Peek()
 755         {
 756             if (navigationPages.Count == 0) return null;
 757
 758             return navigationPages[navigationPages.Count - 1];
 759         }
 760
 761         /// <summary>
 762         /// Gets or sets if Navigator pops the peek page when back button or back key is pressed and released.
 763         /// </summary>
 764         [EditorBrowsable(EditorBrowsableState.Never)]
 765         public bool EnableBackNavigation
 766         {
 767             get
 768             {
 769                 return (bool)GetValue(EnableBackNavigationProperty);
 770             }
 771             set
 772             {
 773                 SetValue(EnableBackNavigationProperty, value);
 774                 NotifyPropertyChanged();
 775             }
 776         }
 777
 778         private bool InternalEnableBackNavigation
 779         {
 780             set
 781             {
 782                 enableBackNavigation = value;
 783             }
 784             get
 785             {
 786                 return enableBackNavigation;
 787             }
 788         }
 789
 790         /// <summary>
 791         /// Disposes Navigator and all children on it.
 792         /// </summary>
 793         /// <param name="type">Dispose type.</param>
 794         [EditorBrowsable(EditorBrowsableState.Never)]
 795         protected override void Dispose(DisposeTypes type)
 796         {
 797             if (disposed)
 798             {
 799                 return;
 800             }
 801
 802             if (type == DisposeTypes.Explicit)
 803             {
 804                 foreach (Page page in navigationPages)
 805                 {
 806                     Utility.Dispose(page);
 807                 }
 808                 navigationPages.Clear();
 809
 810                 Window window;
 811
 812                 if (navigatorWindow.TryGetValue(this, out window) == true)
 813                 {
 814                     navigatorWindow.Remove(this);
 815                     windowNavigator.Remove(window);
 816                 }
 817
 818                 AddedToWindow -= OnAddedToWindow;
 819                 RemovedFromWindow -= OnRemovedFromWindow;
 820             }
 821
 822             base.Dispose(type);
 823         }
 824
 825         /// <summary>
 826         /// Returns the default navigator of the given window.
 827         /// </summary>
 828         /// <returns>The default navigator of the given window.</returns>
 829         /// <exception cref="ArgumentNullException">Thrown when the argument window is null.</exception>
 830         /// <since_tizen> 9 </since_tizen>
 831         public static Navigator GetDefaultNavigator(Window window)
 832         {
 833             if (window == null)
 834             {
 835                 throw new ArgumentNullException(nameof(window), "window should not be null.");
 836             }
 837
 838             if (windowNavigator.ContainsKey(window) == true)
 839             {
 840                 return windowNavigator[window];
 841             }
 842
 843             var defaultNavigator = new Navigator();
 844             defaultNavigator.WidthResizePolicy = ResizePolicyType.FillToParent;
 845             defaultNavigator.HeightResizePolicy = ResizePolicyType.FillToParent;
 846             window.Add(defaultNavigator);
 847             windowNavigator.Add(window, defaultNavigator);
 848             navigatorWindow.Add(defaultNavigator, window);
 849
 850             return defaultNavigator;
 851         }
 852
 853         /// <summary>
 854         /// Called when the back navigation is started.
 855         /// </summary>
 856         /// <param name="eventArgs">The back navigation information.</param>
 857         [EditorBrowsable(EditorBrowsableState.Never)]
 858         protected virtual void OnBackNavigation(BackNavigationEventArgs eventArgs)
 859         {
 860             if (PageCount >= 1)
 861             {
 862                 Tizen.Log.Info("NUI", $"Navigator pops the peek page.\n");
 863                 Pop();
 864             }
 865         }
 866
 867         /// <summary>
 868         /// Called when the back navigation is required outside Navigator.
 869         /// </summary>
 870         internal void NavigateBack()
 871         {
 872             OnBackNavigation(new BackNavigationEventArgs());
 873         }
 874
 875         /// <summary>
 876         /// Create Transitions between currentTopPage and newTopPage
 877         /// </summary>
 878         /// <param name="currentTopPage">The top page of Navigator.</param>
 879         /// <param name="newTopPage">The new top page after transition.</param>
 880         /// <param name="pushTransition">True if this transition is for push new page</param>
 881         private TransitionSet CreateTransitions(Page currentTopPage, Page newTopPage, bool pushTransition)
 882         {
 883             currentTopPage.SetVisible(true);
 884             // Set Content visible because it was hidden by HideContentOfPage.
 885             (currentTopPage as ContentPage)?.Content?.SetVisible(true);
 886
 887             newTopPage.SetVisible(true);
 888             // Set Content visible because it was hidden by HideContentOfPage.
 889             (newTopPage as ContentPage)?.Content?.SetVisible(true);
 890
 891             List<View> taggedViewsInNewTopPage = new List<View>();
 892             RetrieveTaggedViews(taggedViewsInNewTopPage, newTopPage, true);
 893             List<View> taggedViewsInCurrentTopPage = new List<View>();
 894             RetrieveTaggedViews(taggedViewsInCurrentTopPage, currentTopPage, true);
 895
 896             List<KeyValuePair<View, View>> sameTaggedViewPair = new List<KeyValuePair<View, View>>();
 897             foreach (View currentTopPageView in taggedViewsInCurrentTopPage)
 898             {
 899                 bool findPair = false;
 900                 foreach (View newTopPageView in taggedViewsInNewTopPage)
 901                 {
 902                     if ((currentTopPageView.TransitionOptions != null) && (newTopPageView.TransitionOptions != null) &&
 903                         currentTopPageView.TransitionOptions?.TransitionTag == newTopPageView.TransitionOptions?.TransitionTag)
 904                     {
 905                         sameTaggedViewPair.Add(new KeyValuePair<View, View>(currentTopPageView, newTopPageView));
 906                         findPair = true;
 907                         break;
 908                     }
 909                 }
 910                 if (findPair)
 911                 {
 912                     taggedViewsInNewTopPage.Remove(sameTaggedViewPair[sameTaggedViewPair.Count - 1].Value);
 913                 }
 914             }
 915             foreach (KeyValuePair<View, View> pair in sameTaggedViewPair)
 916             {
 917                 taggedViewsInCurrentTopPage.Remove(pair.Key);
 918             }
 919
 920             TransitionSet newTransitionSet = new TransitionSet();
 921             foreach (KeyValuePair<View, View> pair in sameTaggedViewPair)
 922             {
 923                 TransitionItem pairTransition = transition.CreateTransition(pair.Key, pair.Value, pushTransition);
 924                 if (pair.Value.TransitionOptions?.TransitionWithChild ?? false)
 925                 {
 926                     pairTransition.TransitionWithChild = true;
 927                 }
 928                 newTransitionSet.AddTransition(pairTransition);
 929             }
 930
 931             newTransitionSet.Finished += (object sender, EventArgs e) =>
 932             {
 933                 if (newTopPage.Layout != null)
 934                 {
 935                     newTopPage.Layout.RequestLayout();
 936                 }
 937                 if (currentTopPage.Layout != null)
 938                 {
 939                     currentTopPage.Layout.RequestLayout();
 940                 }
 941                 transitionFinished = true;
 942                 InvokeTransitionFinished();
 943                 transitionSet.Dispose();
 944             };
 945
 946             if (!pushTransition || newTopPage is DialogPage == false)
 947             {
 948                 View transitionView = (currentTopPage is ContentPage) ? (currentTopPage as ContentPage).Content : (currentTopPage as DialogPage).Content;
 949                 if (currentTopPage.DisappearingTransition != null && transitionView != null)
 950                 {
 951                     TransitionItemBase disappearingTransition = currentTopPage.DisappearingTransition.CreateTransition(transitionView, false);
 952                     disappearingTransition.TransitionWithChild = true;
 953                     newTransitionSet.AddTransition(disappearingTransition);
 954                 }
 955                 else
 956                 {
 957                     currentTopPage.SetVisible(false);
 958                 }
 959             }
 960             if (pushTransition || currentTopPage is DialogPage == false)
 961             {
 962                 View transitionView = (newTopPage is ContentPage) ? (newTopPage as ContentPage).Content : (newTopPage as DialogPage).Content;
 963                 if (newTopPage.AppearingTransition != null && transitionView != null)
 964                 {
 965                     TransitionItemBase appearingTransition = newTopPage.AppearingTransition.CreateTransition(transitionView, true);
 966                     appearingTransition.TransitionWithChild = true;
 967                     newTransitionSet.AddTransition(appearingTransition);
 968                 }
 969             }
 970
 971             newTransitionSet.Play();
 972
 973             return newTransitionSet;
 974         }
 975
 976         /// <summary>
 977         /// Retrieve Tagged Views in the view tree.
 978         /// </summary>
 979         /// <param name="taggedViews">Returned tagged view list..</param>
 980         /// <param name="view">Root View to get tagged child View.</param>
 981         /// <param name="isRoot">Flag to check current View is page or not</param>
 982         private void RetrieveTaggedViews(List<View> taggedViews, View view, bool isRoot)
 983         {
 984             if (!isRoot && view.TransitionOptions != null)
 985             {
 986                 if (!string.IsNullOrEmpty(view.TransitionOptions?.TransitionTag))
 987                 {
 988                     taggedViews.Add((view as View));
 989                     if (view.TransitionOptions.TransitionWithChild)
 990                     {
 991                         return;
 992                     }
 993                 }
 994
 995             }
 996
 997             foreach (View child in view.Children)
 998             {
 999                 RetrieveTaggedViews(taggedViews, child, false);
1000             }
1001         }
1002
1003         /// <summary>
1004         /// Notify accessibility states change of pages.
1005         /// </summary>
1006         /// <param name="disappearedPage">Disappeared page</param>
1007         /// <param name="appearedPage">Appeared page</param>
1008         private void NotifyAccessibilityStatesChangeOfPages(Page disappearedPage, Page appearedPage)
1009         {
1010             if (disappearedPage != null)
1011             {
1012                 disappearedPage.UnregisterDefaultLabel();
1013                 //We can call disappearedPage.NotifyAccessibilityStatesChange
1014                 //To reduce accessibility events, we are using currently highlighted view instead
1015                 View curHighlightedView = Accessibility.Accessibility.GetCurrentlyHighlightedView();
1016                 if (curHighlightedView != null)
1017                 {
1018                     curHighlightedView.NotifyAccessibilityStatesChange(new AccessibilityStates(AccessibilityState.Visible, AccessibilityState.Showing), AccessibilityStatesNotifyMode.Single);
1019                 }
1020             }
1021
1022             if (appearedPage != null)
1023             {
1024                 appearedPage.RegisterDefaultLabel();
1025                 appearedPage.NotifyAccessibilityStatesChange(new AccessibilityStates(AccessibilityState.Visible, AccessibilityState.Showing), AccessibilityStatesNotifyMode.Single);
1026             }
1027         }
1028
1029         internal void InvokeTransitionFinished()
1030         {
1031             TransitionFinished?.Invoke(this, new EventArgs());
1032         }
1033
1034         //TODO: The following transition codes will be replaced with view transition.
1035         private void InitializeAnimation()
1036         {
1037             if (curAnimation != null)
1038             {
1039                 curAnimation.Stop();
1040                 curAnimation.Clear();
1041                 curAnimation = null;
1042             }
1043
1044             if (newAnimation != null)
1045             {
1046                 newAnimation.Stop();
1047                 newAnimation.Clear();
1048                 newAnimation = null;
1049             }
1050         }
1051
1052         // Show and Register Content of Page to Accessibility bridge
1053         private void ShowContentOfPage(Page page)
1054         {
1055             View content = (page is DialogPage) ? (page as DialogPage)?.Content : (page as ContentPage)?.Content;
1056             if (content != null)
1057             {
1058                 content.Show(); // Calls RegisterDefaultLabel()
1059             }
1060         }
1061
1062         // Hide and Remove Content of Page from Accessibility bridge
1063         private void HideContentOfPage(Page page)
1064         {
1065             View content = (page is DialogPage) ? (page as DialogPage)?.Content : (page as ContentPage)?.Content;
1066             if (content != null)
1067             {
1068                 content.Hide(); // Calls UnregisterDefaultLabel()
1069             }
1070         }
1071     }
1072
1073     /// <summary>
1074     /// BackNavigationEventArgs is a class to record back navigation event arguments which will sent to user.
1075     /// </summary>
1076     [EditorBrowsable(EditorBrowsableState.Never)]
1077     public class BackNavigationEventArgs : EventArgs
1078     {
1079     }
1080 }