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
|
using Android.Content;
using Android.Views;
using Android.Widget;
namespace Xamarin.Forms.Platform.Android
{
public class AHorizontalScrollView : HorizontalScrollView
{
readonly ScrollViewRenderer _renderer;
public AHorizontalScrollView(Context context, ScrollViewRenderer renderer) : base(context)
{
_renderer = renderer;
}
internal bool IsBidirectional { get; set; }
public override bool OnInterceptTouchEvent(MotionEvent ev)
{
// set the start point for the bidirectional scroll;
// Down is swallowed by other controls, so we'll just sneak this in here without actually preventing
// other controls from getting the event.
if (IsBidirectional && ev.Action == MotionEventActions.Down)
{
_renderer.LastY = ev.RawY;
_renderer.LastX = ev.RawX;
}
return base.OnInterceptTouchEvent(ev);
}
public override bool OnTouchEvent(MotionEvent ev)
{
// If the touch is caught by the horizontal scrollview, forward it to the parent so custom renderers can be notified of the touch.
var verticalScrollViewerRenderer = Parent as ScrollViewRenderer;
if (verticalScrollViewerRenderer != null)
{
verticalScrollViewerRenderer.ShouldSkipOnTouch = true;
verticalScrollViewerRenderer.OnTouchEvent(ev);
}
// The nested ScrollViews will allow us to scroll EITHER vertically OR horizontally in a single gesture.
// This will allow us to also scroll diagonally.
// We'll fall through to the base event so we still get the fling from the ScrollViews.
// We have to do this in both ScrollViews, since a single gesture will be owned by one or the other, depending
// on the initial direction of movement (i.e., horizontal/vertical).
if (IsBidirectional)
{
float dX = _renderer.LastX - ev.RawX;
float dY = _renderer.LastY - ev.RawY;
_renderer.LastY = ev.RawY;
_renderer.LastX = ev.RawX;
if (ev.Action == MotionEventActions.Move)
{
var parent = (global::Android.Widget.ScrollView)Parent;
parent.ScrollBy(0, (int)dY);
ScrollBy((int)dX, 0);
}
}
return base.OnTouchEvent(ev);
}
protected override void OnScrollChanged(int l, int t, int oldl, int oldt)
{
base.OnScrollChanged(l, t, oldl, oldt);
_renderer.UpdateScrollPosition(Forms.Context.FromPixels(l), Forms.Context.FromPixels(t));
}
}
}
|
