I am trying to port an Xamarin.Forms app to .NET MAUI but have run into the deprecation of Device.StartTimer, whilst this obviously currently still works in MAUI, I am interested to find out what the alternative is?
Currently I have a wrapper class as follows:
public void Start()
{
if (IsRunning)
{
return;
}
var wrapper = new TaskWrapper(Task, IsRecurring, true);
Tasks.Add(wrapper);
Device.StartTimer(Interval, wrapper.RunTask);
}
I tried replacing this with a System.Timers.Timer however this led to the issue of not being able to modify UI elements due to being on the wrong thread? The timer wrapper itself is used in multiple places so I can't use binding for example in this case either.
Is there actually a direct replacement for Device.StartTimer? Any assistance is greatly appreciated.
The Device timer is obsolete in MAUI.
You can create an IDispatcherTimer instance and subscribe to the Tick event like this:
var timer = Application.Current.Dispatcher.CreateTimer();
timer.Interval = TimeSpan.FromSeconds(1);
timer.Tick += (s,e) => DoSomething();
timer.Start();
Depending on the context that you're using the timer in, you should use the MainThread.BeginInvokeOnMainThread() method to update UI elements:
void DoSomething()
{
MainThread.BeginInvokeOnMainThread(() =>
{
//Update view here
});
}
More info on UI main thread:
https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/appmodel/main-thread
IDispatcherTimer timer;
timer = Dispatcher.CreateTimer();
timer.Interval = TimeSpan.FromMilliseconds(1000);
timer.Tick += (s, e) =>
{
label.Text = DateTime.Now.ToString();
};
timer.Start();
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/button#press-and-release-the-button
Related
Where should I put this chunk of code in order the listener function works every time I enter the app from the deep link?
Now in my unity mobile app I have this code in the initial load, however it does not work well.
The first case of entering the app from the deep link is not being handled. Only after initial load when I click the deep link my listener function works (as the listener is already set).
Is there any solution to this issue?
void Start()
{
DynamicLinks.DynamicLinkReceived += OnDynamicLink;
}
// Display the dynamic link received by the application.
void OnDynamicLink(object sender, EventArgs args)
{
var dynamicLinkEventArgs = args as ReceivedDynamicLinkEventArgs;
Debug.LogFormat("Received dynamic link {0}", dynamicLinkEventArgs.ReceivedDynamicLink.Url.OriginalString);
}
Test this, feel free to edit.
void Start()
{
StartCoroutine(WaitLoader()); //Loader
}
public void trueAwoken()
{
DynamicLinks.DynamicLinkReceived += OnDynamicLink;
}
public IEnumerator WaitLoader()
{
int i = 0;
while (i < 5) // Potential for true load state 5 (increase this 0-1000+?, it depends on your build?)
{
i++;
//Debug.Log("Waiting: " + i + "/" + Time.deltaTime);
yield return new WaitForFixedUpdate();
}
trueAwoken();
}
Greeting,
I'm currently facing a problem that my coroutine can't start. This is the first time I facing this issues and I can't find a proper solution online. Much appreciated if anyone can point me to the right direction to solve this issue.
Here are the code.
path_reference.GetDownloadUrlAsync().ContinueWith((Task<Uri> task) => {
if (!task.IsFaulted && !task.IsCanceled)
{
Debug.Log("Download URL: " + task.Result);
StartCoroutine(DownloadStuff(task.Result));
}
else
{
Debug.Log(task.Exception.ToString());
}
});
}
IEnumerator DownloadStuff(Uri uri)
{
Debug.Log("Start Download");
using (var www = UnityWebRequestTexture.GetTexture(uri))
{
yield return www.SendWebRequest();
if (www.isNetworkError || www.isHttpError)
{
Debug.Log(www.error);
}
else
{
var texture = DownloadHandlerTexture.GetContent(www);
//Texture2D texture = new Texture2D(1, 1);
//if you need sprite for SpriteRenderer or Image
Sprite sprite = Sprite.Create(texture, new Rect(0.0f, 0.0f, texture.width,
texture.height), new Vector2(0.5f, 0.5f), 100.0f);
Debug.Log("Finished downloading!");
}
Debug.Log(www.downloadProgress);
}
}'
The task returned by Firebase probably finishes execution on a thread other than the main thread, and Unity coroutines can only run on the main thread.
Unity's support of multithreading and async is pretty spotty, including "eating" some errors if the continuations of those errors would execute on another thread other than the main thread.
To fix this, you need to change the function that starts your coroutine:
try {
// Important: ConfigureAwait(true) ensures the code after this will run in the
// same thread as the code before (which is the main thread!)
var url = await path_reference.GetDownloadUrlAsync().ConfigureAwait(true);
StartCoroutine(DownloadStuff(url));
} catch (Exception ex) {
// Tip: when logging errors, use LogException and pass the whole exception,
// that way you will get pretty links to the error line in the whole stack trace.
Debug.LogException(ex);
}
As an aside, I usually have a few extension methods on all my projects to deal with that while staying in async-world instead of coroutine-world (because at least with async I can catch errors and not just "halt and catch fire" like Unity's coroutines)
The main ones are:
public static Task ToTask(this YieldInstruction self, MonoBehaviour owner) {
var source = new TaskCompletionSource<object>();
IEnumerable Routine() {
yield return self;
source.SetResult(null);
}
return source.Task;
}
private static Task SendAsync(this UnityWebRequest self, MonoBehaviour owner) {
var source = new TaskCompletionSource<object>();
await self.SendWebRequest().ToTask(owner);
if (
self.isHttpError
|| self.isNetworkError
) {
source.SetException(new Exception(request.error));
yield break;
}
source.SetResult(null);
}
Which you can use like this, inside a MonoBehaviour:
await new WaitForSeconds(0.2f).ToTask(this);
UnityWebRequest request = /* etc */;
await request.SendAsync(this);
var texture = DownloadHandlerTexture.GetContent(request);
Note that these methods do not require ConfigureAwait, since their SetResult/SetException invocations are ran from Unity-provided coroutine continuations.
I'm implementing a DynamicItemStart button inside a Menu Controller. I'm loading the dynamic items for this button when Visual Studio starts. Everything is loaded correctly so the initialize method is called an I see all the new items in this Dynamic button. After the package is completely loaded I want to add more items to this Dynamic button, but since the package is already loaded the initialize method is not called again and I cannot see the new items in this Dynamic button. I only see the ones that were loaded when VS started.
Is there any way that I can force the update of this Dynamic button so it shows the new items?. I want to be able to update the VS UI after I added more items but outside the Initialize method.
The implementation I did is very similar to the one showed on this msdn example:
http://msdn.microsoft.com/en-us/library/bb166492.aspx
Does anyone know if an Update of the UI can be done by demand?
Any hints are greatly appreciated.
I finally got this working. The main thing is the implementation of a derived class of OleMenuCommand that implements a new constructor with a Predicate. This predicate is used to check if a new command is a match within the DynamicItemStart button.
public class DynamicItemMenuCommand : OleMenuCommand
{
private Predicate<int> matches;
public DynamicItemMenuCommand(CommandID rootId, Predicate<int> matches, EventHandler invokeHandler, EventHandler beforeQueryStatusHandler)
: base(invokeHandler, null, beforeQueryStatusHandler, rootId)
{
if (matches == null)
{
throw new ArgumentNullException("Matches predicate cannot be null.");
}
this.matches = matches;
}
public override bool DynamicItemMatch(int cmdId)
{
if (this.matches(cmdId))
{
this.MatchedCommandId = cmdId;
return true;
}
this.MatchedCommandId = 0;
return false;
}
}
The above class should be used when adding the commands on execution time. Here's the code that creates the commands
public class ListMenu
{
private int _baselistID = (int)PkgCmdIDList.cmdidMRUList;
private List<IVsDataExplorerConnection> _connectionsList;
public ListMenu(ref OleMenuCommandService mcs)
{
InitMRUMenu(ref mcs);
}
internal void InitMRUMenu(ref OleMenuCommandService mcs)
{
if (mcs != null)
{
//_baselistID has the guid value of the DynamicStartItem
CommandID dynamicItemRootId = new CommandID(GuidList.guidIDEToolbarCmdSet, _baselistID);
DynamicItemMenuCommand dynamicMenuCommand = new DynamicItemMenuCommand(dynamicItemRootId, isValidDynamicItem, OnInvokedDynamicItem, OnBeforeQueryStatusDynamicItem);
mcs.AddCommand(dynamicMenuCommand);
}
}
private bool IsValidDynamicItem(int commandId)
{
return ((commandId - _baselistID) < connectionsCount); // here is the place to put the criteria to add a new command to the dynamic button
}
private void OnInvokedDynamicItem(object sender, EventArgs args)
{
DynamicItemMenuCommand invokedCommand = (DynamicItemMenuCommand)sender;
if (null != invokedCommand)
{
.....
}
}
private void OnBeforeQueryStatusDynamicItem(object sender, EventArgs args)
{
DynamicItemMenuCommand matchedCommand = (DynamicItemMenuCommand)sender;
bool isRootItem = (matchedCommand.MatchedCommandId == 0);
matchedCommand.Enabled = true;
matchedCommand.Visible = true;
int indexForDisplay = (isRootItem ? 0 : (matchedCommand.MatchedCommandId - _baselistID));
matchedCommand.Text = "Text for the command";
matchedCommand.MatchedCommandId = 0;
}
}
I had to review a lot of documentation since it was not very clear how the commands can be added on execution time. So I hope this save some time whoever has to implement anything similar.
The missing piece for me was figuring out how to control the addition of new items.
It took me some time to figure out that the matches predicate (the IsValidDynamicItem method in the sample) controls how many items get added - as long as it returns true, the OnBeforeQueryStatusDynamicItem gets invoked and can set the details (Enabled/Visible/Checked/Text etc.) of the match to be added to the menu.
When I instantiate a new StageVideo instsance with stage.stageVideos[0] everything works great, but when i leave my view that's displaying the video it sticks on the stage. So when i goto another view it's still showing on the stage in the background. I tried setting sv = null, removing event listeners...etc.
I've created a StageVideoDisplay class which is instantiated in mxml like: and on view initialization i call a play() method:
if ( _path )
{
//...
// Connections
_nc = new NetConnection();
_nc.connect(null);
_ns = new NetStream(_nc);
_ns.addEventListener(NetStatusEvent.NET_STATUS, onNetStatus);
_ns.client = this;
// Screen
_video = new Video();
_video.smoothing = true;
// Video Events
// the StageVideoEvent.STAGE_VIDEO_STATE informs you whether
// StageVideo is available
stage.addEventListener(StageVideoAvailabilityEvent.STAGE_VIDEO_AVAILABILITY,
onStageVideoState);
// in case of fallback to Video, listen to the VideoEvent.RENDER_STATE
// event to handle resize properly and know about the acceleration mode running
_video.addEventListener(VideoEvent.RENDER_STATE, videoStateChange);
//...
}
On video stage event:
if ( stageVideoInUse ) {
try {
_rc = new Rectangle(0,0,this.width,this.height);
_sv.viewPort = _rc;
} catch (e:Error) {}
} else {
try {
_video.width = this.width;
_video.height = this.height;
} catch (e:Error) {}
}
And on stage video availability event:
protected function toggleStageVideo(on:Boolean):void
{
// To choose StageVideo attach the NetStream to StageVideo
if (on)
{
stageVideoInUse = true;
if ( _sv == null )
{
try {
_sv = stage.stageVideos[0];
_sv.addEventListener(StageVideoEvent.RENDER_STATE, stageVideoStateChange);
_sv.attachNetStream(_ns);
_sv.depth = 1;
} catch (e:Error) {}
}
if (classicVideoInUse)
{
// If you use StageVideo, remove from the display list the
// Video object to avoid covering the StageVideo object
// (which is always in the background)
stage.removeChild ( _video );
classicVideoInUse = false;
}
} else
{
// Otherwise attach it to a Video object
if (stageVideoInUse)
stageVideoInUse = false;
classicVideoInUse = true;
try {
_video.attachNetStream(_ns);
stage.addChildAt(_video, 0);
} catch (e:Error) {}
}
if ( !played )
{
played = true;
_ns.play(path);
}
}
What happens is in the view when i navigator.popView(), the stageVideo remains on the stage, even in other views, and when returning to that view to play a different stream the same stream is kind of "burned" on top. I can not figure out a way to get rid of it! Thanks in advance!
In Flash Player 11, Adobe added the dispose() method to the NetStream class.
This is useful to clear the Video or StageVideo object when you're done with it.
When you call the dispose() method at runtime, you may get an exception indicating that there is no property named dispose on the NetStream object.
This occurs because Flash Builder is not compiling the app with the proper SWF version. To fix that, just add this to your compiler directives:
-swf-version=13
In the new Flash Builder 4.7, we hopefully won't have to specify the SWF version to use the newer Flash Player features.
This seems to be the best solution, but if you can't use Flash 11 (or the latest Adobe AIR), some other work arounds would be:
set the viewPort of stage video object to a rectangle that has width=0 and height=0
since stage video appears underneath your app, you can always cover the viewport (with a background color or some DisplayObject)
Ok the issue was actually that, even though it seemed like stage video was in use since i got the "Accelerated" message in status, that it was actually the video render even running and classic video was actually in use. The only thing I needed to do was add stage.removeChild( _video ) to the close() event in the class!!
I am trying to write an application, but it is constantly crashing when using the uiimagepickercontroller. I thought that it might be because I was not disposing of the picker after each use, but it will often freeze up on first run as well. Usually I'll take a picture and it just freezes, never asking to "use" the picture.
Do you have any suggestions? Here is my code. Has anyone gotten this to work?
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
myPicker = new UIImagePickerController();
myPicker.Delegate = new myPickerDelegate(this);
myAlbumButton.Clicked += delegate {
if(UIImagePickerController.IsSourceTypeAvailable(UIImagePickerControllerSourceType.PhotoLibrary)){
myPicker.SourceType = UIImagePickerControllerSourceType.PhotoLibrary;
myPicker.AllowsEditing = true;
this.PresentModalViewController (myPicker, true);
}else{
Console.WriteLine("cannot get album");
}
};
myCameraButton.Clicked += delegate {
if(UIImagePickerController.IsSourceTypeAvailable(UIImagePickerControllerSourceType.Camera)){
myPicker.SourceType = UIImagePickerControllerSourceType.Camera;
//myPicker.AllowsEditing = true;
this.PresentModalViewController (myPicker, true);
}else{
Console.WriteLine("cannot get camera");
}
};
}
private class myPickerDelegate : UIImagePickerControllerDelegate
{
private TestView _vc;
public myPickerDelegate ( TestView controller):base()
{
_vc = controller;
}
public override void FinishedPickingImage (UIImagePickerController myPicker, UIImage image, NSDictionary editingInfo)
{
// TODO: Implement - see: http://go-mono.com/docs/index.aspx?link=T%3aMonoTouch.Foundation.ModelAttribute
_vc.myImageView.Image = image;
myPicker.DismissModalViewControllerAnimated(true);
}
}
Try to call your event handlers code from the main thread by using BeginInvokeOnMainThread().
So my issue was very similar.
Instead of having a delegate class, I had the delegates inline for the picker.
For some reason the app froze every time after talking the image, not stopping in any breakpoint after that.
The solution that worked for me was to use this book:
http://www.scribd.com/doc/33770921/Professional-iPhone-Programming-with-MonoTouch-and-NET-C