/
GestureManager.cs
247 lines (200 loc) · 5.62 KB
/
GestureManager.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
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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using Android.Content;
#if __ANDROID_29__
using AndroidX.Core.View;
#else
using Android.Support.V4.View;
#endif
using Android.Views;
namespace Xamarin.Forms.Platform.Android
{
internal class GestureManager : IDisposable
{
IVisualElementRenderer _renderer;
readonly Lazy<ScaleGestureDetector> _scaleDetector;
readonly Lazy<GestureDetector> _tapAndPanAndSwipeDetector;
bool _disposed;
bool _inputTransparent;
bool _isEnabled;
VisualElement Element => _renderer?.Element;
View View => _renderer?.Element as View;
global::Android.Views.View Control => _renderer?.View;
public GestureManager(IVisualElementRenderer renderer)
{
_renderer = renderer;
_renderer.ElementChanged += OnElementChanged;
_tapAndPanAndSwipeDetector = new Lazy<GestureDetector>(InitializeTapAndPanAndSwipeDetector);
_scaleDetector = new Lazy<ScaleGestureDetector>(InitializeScaleDetector);
}
public bool OnTouchEvent(MotionEvent e)
{
if (Control == null)
{
return false;
}
if (!_isEnabled || _inputTransparent)
{
return false;
}
if (!DetectorsValid())
{
return false;
}
var eventConsumed = false;
if (ViewHasPinchGestures())
{
eventConsumed = _scaleDetector.Value.OnTouchEvent(e);
}
if (!ViewHasPinchGestures() || !_scaleDetector.Value.IsInProgress)
eventConsumed = _tapAndPanAndSwipeDetector.Value.OnTouchEvent(e) || eventConsumed;
return eventConsumed;
}
public class TapAndPanGestureDetector : GestureDetector
{
InnerGestureListener _listener;
public TapAndPanGestureDetector(Context context, InnerGestureListener listener) : base(context, listener)
{
_listener = listener;
InitializeLongPressSettings();
}
void InitializeLongPressSettings()
{
// Right now this just disables long press, since we don't support a long press gesture
// in Forms. If we ever do, we'll need to selectively enable it, probably by hooking into the
// InnerGestureListener and listening for the addition of any long press gesture recognizers.
// (since a long press will prevent a pan gesture from starting, we can't just leave support for it
// on by default).
// Also, since the property is virtual we shouldn't just set it from the constructor.
IsLongpressEnabled = false;
}
public override bool OnTouchEvent(MotionEvent ev)
{
if (base.OnTouchEvent(ev))
return true;
if (ev.Action == MotionEventActions.Up)
_listener.EndScrolling();
return false;
}
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
if (disposing)
{
if (_listener != null)
{
_listener.Dispose();
_listener = null;
}
}
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
bool DetectorsValid()
{
// Make sure we're not testing for gestures on old motion events after our
// detectors have already been disposed
if (_scaleDetector.IsValueCreated && _scaleDetector.Value.Handle == IntPtr.Zero)
{
return false;
}
if (_tapAndPanAndSwipeDetector.IsValueCreated && _tapAndPanAndSwipeDetector.Value.Handle == IntPtr.Zero)
{
return false;
}
return true;
}
GestureDetector InitializeTapAndPanAndSwipeDetector()
{
var context = Control.Context;
var listener = new InnerGestureListener(new TapGestureHandler(() => View, () =>
{
if (Element is View view)
return view.GetChildElements(Point.Zero) ?? new List<GestureElement>();
return new List<GestureElement>();
}),
new PanGestureHandler(() => View, context.FromPixels),
new SwipeGestureHandler(() => View, context.FromPixels));
return new TapAndPanGestureDetector(context, listener);
}
ScaleGestureDetector InitializeScaleDetector()
{
var context = Control.Context;
var listener = new InnerScaleListener(new PinchGestureHandler(() => View), context.FromPixels);
var detector = new ScaleGestureDetector(context, listener, Control.Handler);
ScaleGestureDetectorCompat.SetQuickScaleEnabled(detector, true);
return detector;
}
bool ViewHasPinchGestures()
{
return View != null && View.GestureRecognizers.OfType<PinchGestureRecognizer>().Any();
}
void OnElementChanged(object sender, VisualElementChangedEventArgs e)
{
if (e.OldElement != null)
{
e.OldElement.PropertyChanged -= OnElementPropertyChanged;
}
if (e.NewElement != null)
{
e.NewElement.PropertyChanged += OnElementPropertyChanged;
}
UpdateInputTransparent();
UpdateIsEnabled();
}
void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == VisualElement.InputTransparentProperty.PropertyName)
UpdateInputTransparent();
else if (e.PropertyName == VisualElement.IsEnabledProperty.PropertyName)
UpdateIsEnabled();
}
protected void Dispose(bool disposing)
{
if (_disposed)
{
return;
}
_disposed = true;
if (disposing)
{
_renderer.ElementChanged -= OnElementChanged;
if (Element != null)
{
Element.PropertyChanged -= OnElementPropertyChanged;
}
if (_tapAndPanAndSwipeDetector.IsValueCreated)
{
_tapAndPanAndSwipeDetector.Value.Dispose();
}
if (_scaleDetector.IsValueCreated)
{
_scaleDetector.Value.Dispose();
}
_renderer = null;
}
}
void UpdateInputTransparent()
{
if (Element == null)
{
return;
}
_inputTransparent = Element.InputTransparent;
}
void UpdateIsEnabled()
{
if (Element == null)
{
return;
}
_isEnabled = Element.IsEnabled;
}
}
}