Xamarin.Forms.Platform.Android/AppCompat/FragmentContainer.cs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

using System;
using Android.OS;
using Android.Runtime;
using Android.Support.V4.App;
using Android.Views;
using AView = Android.Views.View;

namespace Xamarin.Forms.Platform.Android.AppCompat
{
	internal class FragmentContainer : Fragment
	{
		readonly WeakReference _pageReference;

		Action<PageContainer> _onCreateCallback;
		bool? _isVisible;
		PageContainer _pageContainer;
		IVisualElementRenderer _visualElementRenderer;

		public FragmentContainer()
		{
		}

		public FragmentContainer(Page page) : this()
		{
			_pageReference = new WeakReference(page);
		}

		protected FragmentContainer(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
		{
		}

		public Page Page => (Page)_pageReference?.Target;

		IPageController PageController => Page as IPageController;

		public override bool UserVisibleHint
		{
			get { return base.UserVisibleHint; }
			set
			{
				base.UserVisibleHint = value;
				if (_isVisible == value)
					return;
				_isVisible = value;
				if (_isVisible.Value)
					PageController?.SendAppearing();
				else
					PageController?.SendDisappearing();
			}
		}

		public static Fragment CreateInstance(Page page)
		{
			return new FragmentContainer(page) { Arguments = new Bundle() };
		}

		public void SetOnCreateCallback(Action<PageContainer> callback)
		{
			_onCreateCallback = callback;
		}

		public override AView OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
		{
			if (Page != null)
			{
				_visualElementRenderer = Android.Platform.CreateRenderer(Page, ChildFragmentManager);
				Android.Platform.SetRenderer(Page, _visualElementRenderer);

				_pageContainer = new PageContainer(Forms.Context, _visualElementRenderer, true);

				_onCreateCallback?.Invoke(_pageContainer);

				return _pageContainer;
			}

			return null;
		}
		
		public override void OnDestroyView()
		{
			if (Page != null)
			{
				if (_visualElementRenderer != null)
				{
					if (_visualElementRenderer.ViewGroup.Handle != IntPtr.Zero)
					{
						_visualElementRenderer.ViewGroup.RemoveFromParent();
					}

					_visualElementRenderer.Dispose();
				}

				if (_pageContainer != null && _pageContainer.Handle != IntPtr.Zero)
				{
					_pageContainer.RemoveFromParent();
					_pageContainer.Dispose();
				}

				Page?.ClearValue(Android.Platform.RendererProperty);
			}

			_onCreateCallback = null;
			_visualElementRenderer = null;
			_pageContainer = null;

			base.OnDestroyView();
		}

		public override void OnHiddenChanged(bool hidden)
		{
			base.OnHiddenChanged(hidden);

			if (Page == null)
				return;

			if (hidden)
				PageController?.SendDisappearing();
			else
				PageController?.SendAppearing();
		}

		public override void OnPause()
		{
			PageController?.SendDisappearing();
			base.OnPause();
		}
		
		public override void OnResume()
		{
			if (UserVisibleHint)
				PageController?.SendAppearing();
			base.OnResume();
		}
	}
}