How can I detect the double tap event for View in Xamarin.Android? I am failing with TouchListener.
There is a SO answer that says double tap is not an Android pattern.
For Native Android (Java), there is an answer, but I want to do that in Xamarin (C#).
It's too easy in c# to do this task. You are new to this world so I'm giving you the exact solution.
First of all you don't have to create a new custom view for this.
Create a class
private class GestureListener : GestureDetector.SimpleOnGestureListener
{
public override bool OnDown(MotionEvent e)
{
return true;
}
public override bool OnDoubleTap(MotionEvent e)
{
return true;
}
}
Now just write this code.
GestureDetector _gestureDetector = new GestureDetector (_context, new GestureListener ());
_gestureDetector.DoubleTap += (object sender, GestureDetector.DoubleTapEventArgs e) => {
//apply double tap code here
};
//apply touch to your view
View1.Touch += (object sender, View.TouchEventArgs e) => {
_gestureDetector.OnTouchEvent (e.Event);
};
I hope this help you.
The first link in your question already contains the answer. A pity it isn't the accepted answer, though. A C# port of the correct answer would be:
public class DoubleTappableView : View
{
private readonly GestureDetector _gestureDetector;
public DoubleTappableView(Context context, IAttributeSet attrs)
: base(context, attrs)
{
_gestureDetector = new GestureDetector(context, new GestureListener());
}
public override bool OnTouchEvent(MotionEvent e)
{
return _gestureDetector.OnTouchEvent(e);
}
private class GestureListener : GestureDetector.SimpleOnGestureListener
{
public override bool OnDown(MotionEvent e)
{
return true;
}
public override bool OnDoubleTap(MotionEvent e)
{
//TODO: Add double tap logic here
return true;
}
}
}
Related
I'm trying to create an extended version of the standard XF Map object:
public class RRMap: Map
{
public void DoSomethingOnMap() {
/* ... */
}
}
I also created an Android renderer (iOS will come later):
[assembly: ExportRenderer(typeof(RRMap), typeof(RRMapRendererAndroid))]
namespace MyApp.Droid.Renderers
{
public class RRMapRendererAndroid : MapRenderer
{
public RRMapRendererAndroid(Context context) : base(context) { }
protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
Control.GetMapAsync(this);
}
}
protected override MarkerOptions CreateMarker(Pin pin)
{
var marker = new MarkerOptions();
marker.SetPosition(new LatLng(pin.Position.Latitude, pin.Position.Longitude));
marker.SetTitle(pin.Label);
marker.SetSnippet(pin.Address);
marker.SetIcon(BitmapDescriptorFactory.DefaultMarker(210));
return marker;
}
}
}
Everything is working fine so far: the map is rendered and pins are created with a custom color.
Unfortunately, I'm stuck on the implementation of DoSomethingOnMap method: it should be a method in the shared code, but it should be implemented in different ways, depending on the platform.
In other circumstances, I would create an interface using DependencyService for implementation, but in this particular case I can't figure out how to proceed.
The first solution is you can use a messaging-center, this can communicate between shared project and iOS/Android project.
Publish a message in the doSomethingOnMap method and anywhere you subscribed to the message will be triggered.
The second is create an event in your shared project and subscribe to that event in the renderer, I wrote both two solutions below:
In your shared project:
public class CustomMap : Map
{
public List<CustomPin> CustomPins { get; set; }
public event EventHandler CallToNativeMethod;
public void doSomething()
{
if (CallToNativeMethod != null)
CallToNativeMethod(this, new EventArgs());
}
public void doSomething(CustomMap myMap) {
MessagingCenter.Send<CustomMap>(this, "Hi");
}
}
In the renderer:
protected override void OnElementChanged(ElementChangedEventArgs<View> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
}
if (e.NewElement != null)
{
MessagingCenter.Subscribe<CustomMap>(this, "Hi", (sender) =>
{
// Do something whenever the "Hi" message is received
Console.WriteLine("hi");
});
((CustomMap)e.NewElement).CallToNativeMethod += (sender, arg) =>
{
Console.WriteLine("native method");
};
}
}
At anywhere you want to call this method:
private void Button_Clicked(object sender, System.EventArgs e)
{
customMap.doSomething();
customMap.doSomething(customMap);
}
I have created a custom menu item which appears in the default menu which pops up when selecting text on my custom WebView.
On clicking on the menu item it calls EvaluateJavascript to get the selected WebView text, and then passes the text to another page.
However after performing this action once or twice, some text on certain areas of the screen start to become unresponsive to clicks eg. text on the parts of the WebView become unselectable, clicks on that part of the screen on other pages becomes unresponsive and even the soft keyboard becomes unclickable in some spots. If this continues for a while sometimes my app will then suddenly freeze the entire operating system and I have to soft reset my phone. It appears that there maybe some serious memory leakage going on.
I create my custom menu item in the MainActivity class:
public override void OnActionModeStarted(ActionMode mode)
{
if (Root.IsCurrentPageType<DictPage>() && DictP.IsWebViewFocused())
{
IMenu menu = mode.Menu;
menu.Add("To Notes");
menu.GetItem(0).SetOnMenuItemClickListener(new MyMenuItemOnMenuItemClickListener(this, mode));
}
base.OnActionModeStarted(mode);
}
It is then handled in the Listener class...
public class MyMenuItemOnMenuItemClickListener : Java.Lang.Object, IMenuItemOnMenuItemClickListener
{
private MainActivity mContext;
ActionMode _mode;
public MyMenuItemOnMenuItemClickListener(MainActivity activity, ActionMode mode)
{
this.mContext = activity;
_mode = mode;
}
public bool OnMenuItemClick(IMenuItem item)
{
WEB.CopyToMainNotes();
Device.BeginInvokeOnMainThread(() =>
{
//close menu if clicked
_mode?.Finish();
});
return true;
}
}
...which calls CopyToMainNotes on my derived WebView class and its associated Renderer and EventHandler classes:
public class WebViewEx : Xamarin.Forms.WebView
{
public static WebViewEx WEB;
//Namespace
//YourClass
public event WebViewExEventHandler CallNativeMethodEvent;
public void CallNativeMethod(WebViewExEventType type)
{
WebViewExEventArgs e = new WebViewExEventArgs();
e.EventType = type;
CallNativeMethodEvent?.Invoke(this, e);
}
public WebViewEx()
{
WEB = this;
}
public void CopyToMainNotes()
{
Device.BeginInvokeOnMainThread(() =>
{
CallNativeMethod(WebViewExEventType.copyToMainNotes);
});
}
}
public delegate void WebViewExEventHandler(object sender, WebViewExEventArgs e);
public class WebViewExEventArgs : EventArgs
{
public enum WebViewExEventType { copyToMainNotes };
public WebViewExEventType EventType = WebViewExEventType.copyToMainNotes;
public WebViewExEventArgs() : base()
{
}
}
public class WebViewExRenderer : WebViewRenderer
{
public WebViewExRenderer(Android.Content.Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
if (Control != null)
{
WebViewEx ex = e.NewElement as WebViewEx;
ex.CallNativeMethodEvent += WebViewEx_CallNativeMethodEvent;
}
}
internal class JavascriptCallback : Java.Lang.Object, IValueCallback
{
public JavascriptCallback(Action<string> callback)
{
_callback = callback;
}
private Action<string> _callback;
public void OnReceiveValue(Java.Lang.Object value)
{
_callback?.Invoke(Convert.ToString(value));
}
}
private void WebViewEx_CallNativeMethodEvent(object sender, WebViewExEventArgs e)
{
switch (e.EventType)
{
case WebViewExEventType.copyToMainNotes:
{
CopyToMainNotes();
break;
}
}
}
public void CopyToMainNotes()
{
string script = "(function(){ return window.getSelection().toString()})()";
var response = string.Empty;
Control?.EvaluateJavascript(script, new JavascriptCallback((r) =>
{
response = r;
Device.BeginInvokeOnMainThread(() =>
{
DPage.CopyThisTextToAnotherPage(response.ToString().Trim('\"'));
});
}));
}
}
The CopyToMainNotes method above is where the EvaluateJavascript takes place and the selected text finally gets sent to another page.
Any ideas where I might be going wrong here? Thanks in advance!
I got sort of a typical music player window, music plays and seekbar point is moving while it plays.
I've done it using default mvvmcross binding to the property (which is changed through the EventHandler binding) like here:
<SeekBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/playprogress"
local:MvxBind="Progress ValueOfTimer"
/>
So now I want the user to be able to move it forward and back.
I've been trying to bind it like this:
public class PlayWindowView : MvxActivity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
var set = this.CreateBindingSet<PlayWindowView, PlayWindowViewModel>();
SeekBar seek = FindViewById<SeekBar>(Resource.Id.playprogress);
set.Bind(seek).For("Max").To(viewModel => viewModel.MaxTimerValue);
set.Bind(seek).For("StopTrackingTouch").To(viewModel => viewModel.PlayProgressChanged);
set.Apply();
}
protected override void OnViewModelSet()
{
SetContentView(Resource.Layout.playwindow_view);
}
}
Viewmodel part looks like this:
public class PlayWindowViewModel : MvxViewModel<ListMenuItemDto>
{
private long _valueOfTimer;
public long ValueOfTimer
{
get { return _valueOfTimer; }
set
{
_valueOfTimer = value;
RaisePropertyChanged(() => ValueOfTimer);
}
}
//...
public MvxAsyncCommand<long> PlayProgressChanged
{
get { return new MvxAsyncCommand<long>(OnPlayProgressChange);}
}
private async Task OnPlayProgressChange(long progr)
{
await _playingService.SetTime((int) progr).ConfigureAwait(false);
}
}
But looks like it's not working.
I mean, it's not even getting into OnPlayProgressChange. But on view is appearing it goes into command PlayProgressChanged one time.
How can I bind this event (and such kind of events like StartTrackingTouch, StopTrackingTouch) to the function correctly?
P.S.
just FYI I using MvvmCross 5
UPD 28.11.2017
Tried custom binding and even Progress binding stoped working now.
So, xaml looks like this now:
<SeekBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/playprogress"
local:MvxBind="Progress ValueOfTimer, OnStopTrackingTouch PlayProgressChanged"
/>
And binder code is here
public class SeekbarStopTrackingTouchEventBinding: MvxAndroidTargetBinding
{
private readonly SeekBar _seekbar;
private IMvxAsyncCommand _command;
public SeekbarStopTrackingTouchEventBinding(SeekBar seekbar) : base(seekbar)
{
_seekbar = seekbar;
_seekbar.StopTrackingTouch += ViewOnStopTrackingTouch;
}
private void ViewOnStopTrackingTouch(object sender, SeekBar.StopTrackingTouchEventArgs e)
{
if (_command != null)
{
_command.Execute(e);
}
}
public override Type TargetType
{
get { return typeof (IMvxAsyncCommand); }
}
protected override void SetValueImpl(object target, object value)
{
_command = (IMvxAsyncCommand)value;
}
protected override void Dispose(bool isDisposing)
{
if (isDisposing)
{
_seekbar.StopTrackingTouch -= ViewOnStopTrackingTouch;
}
base.Dispose(isDisposing);
}
public override MvxBindingMode DefaultMode
{
get { return MvxBindingMode.OneWay; }
}
}
}
In Setup:
protected override void FillTargetFactories(IMvxTargetBindingFactoryRegistry registry)
{
base.FillTargetFactories(registry);
registry.RegisterFactory(new MvxCustomBindingFactory<SeekBar>("OnStopTrackingTouch", (seekbar) => new SeekbarStopTrackingTouchEventBinding(seekbar)));
}
UPD2
Changed binding like this: local:MvxBind="Progress ValueOfTimer; OnStopTrackingTouch PlayProgressChanged" (notice ; here) and event fires now, yes!
But now the thing is - in binder _command is stays null even after SetValueImpl fired and _command = (IMvxAsyncCommand)value; is fine, value points to setted ViewModel property.
How come?
UPD3
Found out it can't cast object to IMvxAsyncCommand.
I fixed that by changing
IMvxAsyncCommand _command to IMvxAsyncCommand<SeekBar.StopTrackingTouchEventArgs> _command;
Will sum everything up in the answer.
But now I got the question - whats best practice in this case?
So, I don't know if it's a good way, but for now its working and I'm kinda happy with it.
Hope this would help somebody like me.
Custom Bindings approach is the key here. Really useful stuff is here:
In MvvmCross how do I do custom bind properties
MvvmCross Custom Event Binding Event Args
MVVMCross Bindings in Android
So, in my case, to make app listen to SeekBar OnStopTrackingTouch event I done this:
Created binding class:
public class SeekbarStopTrackingTouchEventBinding: MvxAndroidTargetBinding
{
private readonly SeekBar _seekbar;
private IMvxAsyncCommand<SeekBar.StopTrackingTouchEventArgs> _command;
private string testString;
public SeekbarStopTrackingTouchEventBinding(SeekBar seekbar) : base(seekbar)
{
_seekbar = seekbar;
_seekbar.StopTrackingTouch += ViewOnStopTrackingTouch;
}
private void ViewOnStopTrackingTouch(object sender, SeekBar.StopTrackingTouchEventArgs e)
{
if (_command != null)
{
_command.Execute(e);
}
}
public override Type TargetType
{
get { return typeof (IMvxAsyncCommand); }
}
protected override void SetValueImpl(object target, object value)
{
try
{
_command = (IMvxAsyncCommand<SeekBar.StopTrackingTouchEventArgs>)value;
}
catch (Exception e)
{
Log.Error("SOME BINDER FAIL\n\t" + e.Message + "\n", "SOME BINDER FAIL\n\t" + e.Message + "\n");
throw;
}
}
protected override void Dispose(bool isDisposing)
{
if (isDisposing)
{
_seekbar.StopTrackingTouch -= ViewOnStopTrackingTouch;
}
base.Dispose(isDisposing);
}
public override MvxBindingMode DefaultMode
{
get { return MvxBindingMode.OneWay; }
}
}
In Setup.cs placed this code:
protected override void FillTargetFactories(IMvxTargetBindingFactoryRegistry registry)
{
base.FillTargetFactories(registry);
registry.RegisterFactory(new MvxCustomBindingFactory<SeekBar>("OnStopTrackingTouch", (seekbar) => new SeekbarStopTrackingTouchEventBinding(seekbar)));
}
Prepared property in my ViewModel and command executing function:
public IMvxAsyncCommand<SeekBar.StopTrackingTouchEventArgs> PlayProgressChanged
{
get
{
return new MvxAsyncCommand<SeekBar.StopTrackingTouchEventArgs>(OnPlayProgressChange);
}
}
private async Task OnPlayProgressChange(SeekBar.StopTrackingTouchEventArgs e)
{
var progr = e.SeekBar.Progress;
await _playingService.SetTime((int) progr).ConfigureAwait(false);
}
In view layout, inside local:MvxBind linked my ViewModel command with evend name, provided in registry.RegisterFactory in Setup.cs
<SeekBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/playprogress"
local:MvxBind="Progress ValueOfTimer; OnStopTrackingTouch PlayProgressChanged"
/>
I'm porting to Xamarin.IOS a swift library that makes some material design animation with UIButton.
The swift counterpart is a subclass of UIButton and overrides layoutSublayersOfLayer.
Swift:
public override func layoutSublayersOfLayer(layer: CALayer) {
super.layoutSublayersOfLayer(layer)
if self.layer == layer {
layoutShape()
layoutVisualLayer()
}
}
On Xamarin side I noted that this method is called through CALayerDelegate, which is associated with CALayer through de property Delegate.
I tried to subclass CALayerDelegate and replace de Delegate property, but when I did that the button didn't rendered correctly and stopped respond to events.
Is there a way to override layoutSublayersOfLayer on Xamarin.Ios ? Is there another method that I can override to prepare stuff before a particular layer is drawn ?
public class MaterialButtonLayerDelegate : CALayerDelegate
{
private readonly MaterialButton _button;
public MaterialButtonLayerDelegate(MaterialButton button):base()
{
_button = button;
}
public override void LayoutSublayersOfLayer(CALayer layer)
{
if (_button.Layer == layer)
{
_button.LayoutShape();
_button.LayoutVisualLayer();
}
}
}
[Register("MaterialButton")]
public class MaterialButton : UIButton
{
public CAShapeLayer VisualLayer { get; private set; } = new CAShapeLayer();
public MaterialButton(CGRect frame):base(frame)
{
PrepareView();
}
protected void PrepareView()
{
Layer.Delegate = new MaterialButtonLayerDelegate(this);
ContentScaleFactor = MaterialDevice.Scale();
PrepareVisualLayer();
}
protected virtual void PrepareVisualLayer()
{
VisualLayer.ZPosition = 0;
VisualLayer.MasksToBounds = true;
Layer.AddSublayer(VisualLayer);
}
protected virtual void LayoutShape()
{
//...
}
protected virtual void LayoutVisualLayer()
{
//...
}
}
Thanks!
The only possible way to do it is extending CALayerDelegate class and setting it as your CAShapeLayer delegate. Be sure to call delegate's base members wherever possible as it performs required bindings behind the scenes.
public override void LayoutSublayersOfLayer(CALayer layer)
{
base.LayoutSublayersOfLayer(layer);
if (_button.Layer == layer)
{
_button.LayoutShape();
_button.LayoutVisualLayer();
}
}
How to create custom bindings for Windows Phone?
I need to do something like this (but this example for Android):
answer
Custom bindings in Android:
public class LongClickEventBinding
: MvxBaseAndroidTargetBinding
{
private readonly View _view;
private IMvxCommand _command;
public LongPressEventBinding(View view)
{
_view = view;
_view.LongClick += ViewOnLongClick;
}
private void ViewOnLongClick(object sender, View.LongClickEventArgs eventArgs)
{
if (_command != null)
{
_command.Execute();
}
}
public override void SetValue(object value)
{
_command = (IMvxCommand)value;
}
protected override void Dispose(bool isDisposing)
{
if (isDisposing)
{
_view.Click -= ViewOnLongClick;
}
base.Dispose(isDisposing);
}
public override Type TargetType
{
get { return typeof(IMvxCommand); }
}
public override MvxBindingMode DefaultMode
{
get { return MvxBindingMode.OneWay; }
}
}
Excuse me for the improper question..
As far as I understood your question, you don't need to develop anything at all. Use Blend to apply & setup CallMethodAction built-in behavior, and implement public method in your VM class.
WP7 doesn't expose Tap and Hold as an event.
However, I believe you can access this sort og thing in Wp7 and Wp8 using Gestures - e.g.
http://blogs.claritycon.com/windowsphone7/2010/07/wp7-gesture-recognizer-and-behavior-triggers/
http://www.windowsphonegeek.com/articles/WP7-GestureService-in-depth--key-concepts-and-API