/
DragAndDropGestureHandler.cs
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/
DragAndDropGestureHandler.cs
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using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Android.Content;
using Android.Views;
using Microsoft.Maui.Controls.Platform;
using ADragFlags = Android.Views.DragFlags;
using AUri = Android.Net.Uri;
using AView = Android.Views.View;
namespace Microsoft.Maui.Controls.Compatibility.Platform.Android
{
class DragAndDropGestureHandler : Java.Lang.Object, AView.IOnDragListener
{
bool _isDisposed;
CustomLocalStateData _currentCustomLocalStateData;
public DragAndDropGestureHandler(Func<View> getView, Func<AView> getControl)
{
_ = getView ?? throw new ArgumentNullException(nameof(getView));
_ = getControl ?? throw new ArgumentNullException(nameof(getControl));
GetView = getView;
GetControl = getControl;
SetupHandlerForDrop();
}
Func<View> GetView { get; }
Func<AView> GetControl { get; }
public bool HasAnyDragGestures()
{
var gestures = GetView()?.GestureRecognizers;
if (gestures == null || gestures.Count == 0)
return false;
foreach (var gesture in gestures)
if (gesture is DragGestureRecognizer)
return true;
return false;
}
public bool HasAnyDropGestures()
{
var gestures = GetView()?.GestureRecognizers;
if (gestures == null || gestures.Count == 0)
return false;
foreach (var gesture in gestures)
if (gesture is DropGestureRecognizer)
return true;
return false;
}
public void SetupHandlerForDrop()
{
if (HasAnyDropGestures())
GetControl()?.SetOnDragListener(this);
else
GetControl()?.SetOnDragListener(null);
}
protected override void Dispose(bool disposing)
{
if (_isDisposed)
return;
_isDisposed = true;
if (disposing)
{
_currentCustomLocalStateData = null;
var control = GetControl();
if (control.IsAlive())
{
control.SetOnDragListener(null);
}
}
base.Dispose(disposing);
}
void SendEventArgs<TRecognizer>(Action<TRecognizer> func, View view = null)
{
view = view ?? GetView();
if (view == null)
return;
var gestures =
view
.GestureRecognizers?
.OfType<TRecognizer>();
if (gestures == null)
return;
foreach (var gesture in gestures)
{
func(gesture);
}
}
public bool OnDrag(AView v, DragEvent e)
{
DataPackage package = null;
CustomLocalStateData localStateData = (e.LocalState as CustomLocalStateData) ?? _currentCustomLocalStateData ?? new CustomLocalStateData();
_currentCustomLocalStateData = localStateData;
IVisualElementRenderer dragSourceRenderer = localStateData?.SourceNativeView as IVisualElementRenderer;
package = localStateData?.DataPackage;
var dragSourceElement = _currentCustomLocalStateData?.SourceElement ?? dragSourceRenderer?.Element;
if (package == null)
{
package = new DataPackage();
_currentCustomLocalStateData.DataPackage = package;
}
switch (e.Action)
{
case DragAction.Ended:
{
_currentCustomLocalStateData = null;
if (dragSourceElement is View vSource)
{
HandleDropCompleted(vSource);
}
}
break;
case DragAction.Started:
break;
case DragAction.Location:
HandleDragOver(package);
break;
case DragAction.Drop:
{
HandleDrop(e, _currentCustomLocalStateData);
break;
}
case DragAction.Entered:
HandleDragOver(package);
break;
case DragAction.Exited:
HandleDragLeave(package);
break;
}
return true;
}
void HandleDropCompleted(View element)
{
var args = new DropCompletedEventArgs();
SendEventArgs<DragGestureRecognizer>(rec => rec.SendDropCompleted(args), element);
}
bool HandleDragLeave(DataPackage package)
{
var dragEventArgs = new DragEventArgs(package);
bool validTarget = false;
SendEventArgs<DropGestureRecognizer>(rec =>
{
if (!rec.AllowDrop)
return;
rec.SendDragLeave(dragEventArgs);
validTarget = validTarget || dragEventArgs.AcceptedOperation != DataPackageOperation.None;
_currentCustomLocalStateData.AcceptedOperation = dragEventArgs.AcceptedOperation;
});
return validTarget;
}
bool HandleDragOver(DataPackage package)
{
var dragEventArgs = new DragEventArgs(package);
bool validTarget = false;
SendEventArgs<DropGestureRecognizer>(rec =>
{
if (!rec.AllowDrop)
return;
rec.SendDragOver(dragEventArgs);
validTarget = validTarget || dragEventArgs.AcceptedOperation != DataPackageOperation.None;
_currentCustomLocalStateData.AcceptedOperation = dragEventArgs.AcceptedOperation;
});
return validTarget;
}
void HandleDrop(DragEvent e, CustomLocalStateData customLocalStateData)
{
if (customLocalStateData.AcceptedOperation == DataPackageOperation.None)
return;
var datapackage = customLocalStateData.DataPackage;
if (e.LocalState == null)
{
string text = String.Empty;
if (e.ClipData?.ItemCount > 0)
{
var clipData = e.ClipData.GetItemAt(0);
var control = GetControl();
if (control?.Context != null)
text = clipData.CoerceToText(control?.Context);
else
text = clipData.Text;
}
else
{
text = e.ClipDescription?.Label;
}
if (String.IsNullOrWhiteSpace(datapackage.Text))
datapackage.Text = text;
if (datapackage.Image == null)
datapackage.Image = text;
}
var args = new DropEventArgs(datapackage?.View);
SendEventArgs<DropGestureRecognizer>(async rec =>
{
if (!rec.AllowDrop)
return;
try
{
await rec.SendDrop(args);
}
catch (Exception exc)
{
Internals.Log.Warning(nameof(DropGestureRecognizer), $"{exc}");
}
});
}
public void OnLongPress(MotionEvent e)
{
if (!HasAnyDragGestures())
return;
SendEventArgs<DragGestureRecognizer>(rec =>
{
if (!rec.CanDrag)
return;
var element = GetView();
var renderer = Platform.GetRenderer(element);
var v = renderer.View;
if (v.Handle == IntPtr.Zero)
return;
var args = rec.SendDragStarting(element);
if (args.Cancel)
return;
CustomLocalStateData customLocalStateData = new CustomLocalStateData();
customLocalStateData.DataPackage = args.Data;
//_dragSource[element] = args.Data;
string clipDescription = AutomationPropertiesProvider.ConcatenateNameAndHelpText(element) ?? String.Empty;
ClipData.Item item = null;
List<string> mimeTypes = new List<string>();
if (!args.Handled)
{
if (args.Data.Image != null)
{
mimeTypes.Add("image/jpeg");
item = ConvertToClipDataItem(args.Data.Image, mimeTypes);
}
else
{
string text = clipDescription ?? args.Data.Text;
if (Uri.TryCreate(text, UriKind.Absolute, out _))
{
item = new ClipData.Item(AUri.Parse(text));
mimeTypes.Add(ClipDescription.MimetypeTextUrilist);
}
else
{
item = new ClipData.Item(text);
mimeTypes.Add(ClipDescription.MimetypeTextPlain);
}
}
}
var dataPackage = args.Data;
ClipData.Item userItem = null;
if (dataPackage.Image != null)
userItem = ConvertToClipDataItem(dataPackage.Image, mimeTypes);
if (dataPackage.Text != null)
userItem = new ClipData.Item(dataPackage.Text);
if (item == null)
{
item = userItem;
userItem = null;
}
ClipData data = new ClipData(clipDescription, mimeTypes.ToArray(), item);
if (userItem != null)
data.AddItem(userItem);
var dragShadowBuilder = new AView.DragShadowBuilder(v);
customLocalStateData.SourceNativeView = v;
customLocalStateData.SourceElement = renderer?.Element;
if (Forms.IsNougatOrNewer)
v.StartDragAndDrop(data, dragShadowBuilder, customLocalStateData, (int)ADragFlags.Global | (int)ADragFlags.GlobalUriRead);
else
#pragma warning disable CS0618 // Type or member is obsolete
v.StartDrag(data, dragShadowBuilder, customLocalStateData, (int)ADragFlags.Global | (int)ADragFlags.GlobalUriRead);
#pragma warning restore CS0618 // Type or member is obsolete
});
}
ClipData.Item ConvertToClipDataItem(ImageSource source, List<string> mimeTypes)
{
if (source is UriImageSource uriImageSource)
{
if (!mimeTypes.Contains(ClipDescription.MimetypeTextUrilist))
mimeTypes.Add(ClipDescription.MimetypeTextUrilist);
var aUri = AUri.Parse(uriImageSource.Uri.ToString());
return new ClipData.Item(aUri);
}
else if (source is FileImageSource fileImageSource && File.Exists(fileImageSource.File))
{
var aUri = AUri.FromFile(new Java.IO.File(fileImageSource.File));
return new ClipData.Item(aUri);
}
return new ClipData.Item(source?.ToString() ?? String.Empty);
}
class CustomLocalStateData : Java.Lang.Object
{
public AView SourceNativeView { get; set; }
public DataPackage DataPackage { get; set; }
public DataPackageOperation AcceptedOperation { get; set; } = DataPackageOperation.Copy;
public VisualElement SourceElement { get; set; }
}
}
}