src/Tizen.NUI/src/internal/Common/BackKeyManager.cs

   1 /*
   2  * Copyright(c) 2020 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 using System;
  18 using System.ComponentModel;
  19 using System.Collections.Generic;
  20 using Tizen.NUI.BaseComponents;
  21
  22 namespace Tizen.NUI
  23 {
  24     /// <summary>
  25     /// BackKeyManager is a class to manager back key event.
  26     /// </summary>
  27     [EditorBrowsable(EditorBrowsableState.Never)]
  28     public sealed class BackKeyManager
  29     {
  30         private static readonly BackKeyManager instance = new BackKeyManager();
  31
  32         /// <summary>
  33         /// BackKeyManager construct.
  34         /// </summary>
  35         private BackKeyManager()
  36         {
  37             NUIApplication.GetDefaultWindow().KeyEvent += OnWindowKeyEvent;
  38         }
  39
  40         /// <summary>
  41         /// Subscriber.
  42         /// </summary>
  43         [EditorBrowsable(EditorBrowsableState.Never)]
  44         public List<View> Subscriber { get; } = new List<View>();
  45
  46         /// <summary>
  47         /// BackKeyManager static instance.
  48         /// </summary>
  49         [EditorBrowsable(EditorBrowsableState.Never)]
  50         public static BackKeyManager Instance { get { return instance; } }
  51
  52         private Container FindParent(Container child, int step)
  53         {
  54             Container result = child;
  55
  56             for (int i = 0; i < step; i++)
  57             {
  58                 result = result?.GetParent();
  59             }
  60
  61             return result;
  62         }
  63
  64         // If false, comparison1 is on top and if true, comparison2 is on top.
  65         private bool CompareElevation(Container comparison1, Container comparison2)
  66         {
  67             bool result = false;
  68
  69             Container parent1 = comparison1?.GetParent();
  70             Container parent2 = comparison2?.GetParent();
  71
  72             if ((parent1 == null && parent2 != null) || (parent2 == null && parent1 != null))
  73             {
  74                 // One is in DefaultLayer but the other is not
  75                 if (parent2 == null)
  76                 {
  77                     // parent1 is in DefaultLayer.
  78                     Layer comparison2AsLayer = comparison2 as Layer;
  79                     if (comparison2AsLayer != null)
  80                     {
  81                         result = comparison2AsLayer.Depth > NUIApplication.GetDefaultWindow().GetDefaultLayer().Depth;
  82                     }
  83                 }
  84                 else
  85                 {
  86                     // parent2 is in DefaultLayer.
  87                     Layer comparison1AsLayer = comparison1 as Layer;
  88                     if (comparison1AsLayer != null)
  89                     {
  90                         result = NUIApplication.GetDefaultWindow().GetDefaultLayer().Depth < comparison1AsLayer.Depth;
  91                     }
  92                 }
  93             }
  94             else
  95             {
  96                 // If they have same parent, ready to compare!
  97                 if (parent1 == parent2)
  98                 {
  99
 100                     if (comparison1.GetType().FullName.Contains("Layer"))
 101                     {
 102                         // If comparison1 is Layer, comparison2 is also Layer because only window can have Layer as child in NUI.
 103                         // Compare Depth
 104                         Layer comparison1AsLayer = comparison1 as Layer;
 105                         Layer comparison2AsLayer = comparison2 as Layer;
 106                         if (comparison1AsLayer != null && comparison2AsLayer != null)
 107                         {
 108                             result = comparison1AsLayer.Depth < comparison2AsLayer.Depth;
 109                         }
 110                     }
 111                     else
 112                     {
 113                         // If comparison1 is View, comparison2 is also View because only window can have Layer as child in NUI.
 114                         // Compare SiblingOrder
 115                         View comparison1AsView = comparison1 as View;
 116                         View comparison2AsView = comparison2 as View;
 117                         if (comparison1AsView != null && comparison2AsView != null)
 118                         {
 119                             result = comparison1AsView.SiblingOrder < comparison2AsView.SiblingOrder;
 120                         }
 121                     }
 122                 }
 123                 else
 124                 {
 125                     // Check ancestor
 126                     result = CompareElevation(parent1, parent2);
 127                 }
 128             }
 129
 130             return result;
 131         }
 132
 133         private void OnWindowKeyEvent(object source, Window.KeyEventArgs args)
 134         {
 135             if (args.Key.State == Key.StateType.Up && (args.Key.KeyPressedName == "Back" || args.Key.KeyPressedName == "XF86Back"))
 136             {
 137                 View top = null;
 138
 139                 for (int i = 0; i < Subscriber.Count; i++)
 140                 {
 141                     // Check visibility
 142                     if (Subscriber[i].Visibility && Subscriber[i].IsOnWindow)
 143                     {
 144                         // Initialize first top
 145                         if (top == null)
 146                         {
 147                             top = Subscriber[i];
 148                             continue;
 149                         }
 150                         else
 151                         {
 152                             if (top.HierarchyDepth != Subscriber[i].HierarchyDepth)
 153                             {
 154                                 Container compare1 = top;
 155                                 Container compare2 = Subscriber[i];
 156
 157                                 // If their depth is different, sync.
 158                                 if (top.HierarchyDepth > Subscriber[i].HierarchyDepth)
 159                                 {
 160                                     compare1 = FindParent(compare1, top.HierarchyDepth - Subscriber[i].HierarchyDepth);
 161                                 }
 162                                 else
 163                                 {
 164                                     compare2 = FindParent(compare2, Subscriber[i].HierarchyDepth - top.HierarchyDepth);
 165                                 }
 166
 167                                 if (compare1 == compare2)
 168                                 {
 169                                     // One is descendant of the other. Descendant is above ancestor.
 170                                     top = top.HierarchyDepth > Subscriber[i].HierarchyDepth ? top : Subscriber[i];
 171                                 }
 172                                 else
 173                                 {
 174                                     // Need to compare.
 175                                     top = CompareElevation(compare1, compare2) ? Subscriber[i] : top;
 176                                 }
 177                             }
 178                             else
 179                             {
 180                                 top = CompareElevation(top, Subscriber[i]) ? Subscriber[i] : top;
 181                             }
 182                         }
 183                     }
 184                 }
 185
 186                 top?.EmitBackKeyPressed();
 187             }
 188         }
 189     }
 190 }