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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
using System;
using System.ComponentModel;
using System.Threading.Tasks;
using AImageView = Android.Widget.ImageView;
using AView = Android.Views.View;
using Android.Views;
using Xamarin.Forms.Internals;
namespace Xamarin.Forms.Platform.Android.FastRenderers
{
internal sealed class ImageRenderer : AImageView, IVisualElementRenderer, IImageRendererController
{
bool _disposed;
Image _element;
bool _skipInvalidate;
int? _defaultLabelFor;
VisualElementTracker _visualElementTracker;
VisualElementRenderer _visualElementRenderer;
readonly MotionEventHelper _motionEventHelper = new MotionEventHelper();
protected override void Dispose(bool disposing)
{
if (_disposed)
return;
_disposed = true;
if (disposing)
{
if (_visualElementTracker != null)
{
_visualElementTracker.Dispose();
_visualElementTracker = null;
}
if (_visualElementRenderer != null)
{
_visualElementRenderer.Dispose();
_visualElementRenderer = null;
}
if (_element != null)
{
_element.PropertyChanged -= OnElementPropertyChanged;
if (Platform.GetRenderer(_element) == this)
_element.ClearValue(Platform.RendererProperty);
}
}
base.Dispose(disposing);
}
public override void Invalidate()
{
if (_skipInvalidate)
{
_skipInvalidate = false;
return;
}
base.Invalidate();
}
async void OnElementChanged(ElementChangedEventArgs<Image> e)
{
await TryUpdateBitmap(e.OldElement);
UpdateAspect();
this.EnsureId();
ElementChanged?.Invoke(this, new VisualElementChangedEventArgs(e.OldElement, e.NewElement));
}
public override bool OnTouchEvent(MotionEvent e)
{
if (_visualElementRenderer.OnTouchEvent(e))
{
return true;
}
return _motionEventHelper.HandleMotionEvent(Parent, e);
}
Size MinimumSize()
{
return new Size();
}
SizeRequest IVisualElementRenderer.GetDesiredSize(int widthConstraint, int heightConstraint)
{
if (_disposed)
{
return new SizeRequest();
}
Measure(widthConstraint, heightConstraint);
return new SizeRequest(new Size(MeasuredWidth, MeasuredHeight), MinimumSize());
}
void IVisualElementRenderer.SetElement(VisualElement element)
{
if (element == null)
throw new ArgumentNullException(nameof(element));
var image = element as Image;
if (image == null)
throw new ArgumentException("Element is not of type " + typeof(Image), nameof(element));
Image oldElement = _element;
_element = image;
Internals.Performance.Start();
if (oldElement != null)
oldElement.PropertyChanged -= OnElementPropertyChanged;
element.PropertyChanged += OnElementPropertyChanged;
if (_visualElementTracker == null)
_visualElementTracker = new VisualElementTracker(this);
if (_visualElementRenderer == null)
{
_visualElementRenderer = new VisualElementRenderer(this);
}
Internals.Performance.Stop();
_motionEventHelper.UpdateElement(element);
OnElementChanged(new ElementChangedEventArgs<Image>(oldElement, _element));
_element?.SendViewInitialized(Control);
}
void IVisualElementRenderer.SetLabelFor(int? id)
{
if (_defaultLabelFor == null)
_defaultLabelFor = LabelFor;
LabelFor = (int)(id ?? _defaultLabelFor);
}
void IVisualElementRenderer.UpdateLayout() => _visualElementTracker?.UpdateLayout();
VisualElement IVisualElementRenderer.Element => _element;
VisualElementTracker IVisualElementRenderer.Tracker => _visualElementTracker;
AView IVisualElementRenderer.View => this;
ViewGroup IVisualElementRenderer.ViewGroup => null;
void IImageRendererController.SkipInvalidate() => _skipInvalidate = true;
AImageView Control => this;
public event EventHandler<VisualElementChangedEventArgs> ElementChanged;
public event EventHandler<PropertyChangedEventArgs> ElementPropertyChanged;
public ImageRenderer() : base(Forms.Context)
{
}
async void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == Image.SourceProperty.PropertyName)
await TryUpdateBitmap();
else if (e.PropertyName == Image.AspectProperty.PropertyName)
UpdateAspect();
ElementPropertyChanged?.Invoke(this, e);
}
async Task TryUpdateBitmap(Image previous = null)
{
// By default we'll just catch and log any exceptions thrown by UpdateBitmap so they don't bring down
// the application; a custom renderer can override this method and handle exceptions from
// UpdateBitmap differently if it wants to
try
{
await UpdateBitmap(previous);
}
catch (Exception ex)
{
Log.Warning(nameof(ImageRenderer), "Error loading image: {0}", ex);
}
finally
{
((IImageController)_element)?.SetIsLoading(false);
}
}
async Task UpdateBitmap(Image previous = null)
{
if (_element == null || _disposed)
{
return;
}
await Control.UpdateBitmap(_element, previous);
}
void UpdateAspect()
{
if (_element == null || _disposed)
{
return;
}
ScaleType type = _element.Aspect.ToScaleType();
SetScaleType(type);
}
}
}
|
