Develop Reference

How to Run script when unity load just once?

Here, I am looking for a piece of code in the Unity editor that will execute the initial panel of the created package only once when Unity is opened, but this code is executed in the initial frame every time I play Unity and then stop it, and it continuously shows the panel. Gives. I want it to be seen only once when the project is opened.
[InitializeOnLoad]
public class Autorun
{
static Autorun()
{
EditorApplication.update += RunOnce;
}
static void RunOnce()
{
Debug.Log("Once"); // but it will repeat every time I Clicking on play then stop it.
Panel.Init();
EditorApplication.update -= RunOnce;
}
}
Above is the code suggested by the user in Unity Answers, which was chosen as the best answer, but in fact, as I pointed out, it had a problem.

Although it was mentioned in the comment that the second answer in Unity answers solves the problem, after a while I noticed that the panel opens again when saving the code and I could not find a way to block it through another condition in EditorApplication. The solution below is the final method of solving the problem that uses EditorPrefs and I feel it necessary to share this method with you.
internal const string FIRST_TIME = "FIRST_TIME"; // the key
static Autorun()
{
EditorApplication.update += RunOnce;
EditorApplication.quitting += Quit;
}
private static void Quit() => EditorPrefs.DeleteKey(FIRST_TIME);
private static void RunOnce()
{
var firstTime = EditorPrefs.GetBool(FIRST_TIME, true);
Debug.Log(firstTime);
if (firstTime)
{
EditorPrefs.SetBool(FIRST_TIME, false);
if (EditorPrefs.GetBool(Panel.ShowOnStart, true)) Panel.Init();
}
EditorApplication.update -= RunOnce;
}
}

Xamarin iOS app freezes: ViewDidAppear() never gets called

This seems to be a tricky one:
We're working on a Xamarin iOS app that has a UITableView control displaying a list of profiles. Once the user clicks on one of the profiles we'd like to switch to a separate "ProfileViewController" to display more detailed information. This works just fine for 99.9% of the time. In the remaining ~0.1% the item in the list gets highlighted (which happens OnClick) but the app just seemingly freezes and never switches to the other ViewController, leaving the user with an unresponsive list.
The interesting thing to note here is that the app doesn't really freeze, as the simple "swipe back" gesture brings the user back to the UITableView (to be clear the switch-to-profile-viewcontroller animation is never played so it basically switches from the unresponsive list back to the same list, but now it is responsive again).
The tricky thing is that we can't reliably reproduce this bug. It just seems to happen at random, sometimes while stuff is running in the background, other times while the app was previously in an idle state. We are pretty sure that it isn't related to multithreading (we triple-checked everything, using locking and semaphores where necessary), it rather seems to be some rendering issue (as you can still swipe back to the previous screen or at least it isn't your common dead lock).
Using a bunch of Console.WriteLine() tracers and hours of trial and error reproducing this bug we could isolate the problem and discovered the following:
Upon clicking on the list code in ViewDidLoad() and ViewWillAppear() is successfully executed. However ViewDidAppear() never gets invoked. There is nothing else happening in our code or on different threads between ViewWillAppear() and ViewDidAppear() and we don't have any funky / unusual code that gets executed previously (just the usual UI initialization like this in ViewDidLoad()):
...
LblProfileName.TextAlignment = UITextAlignment.Center;
LblProfileName.Text = string.Empty;
LblProfileName.Font = FontAgent.ForSize(30);
LblProfileSlogan.TextAlignment = UITextAlignment.Center;
LblProfileSlogan.Text = string.Empty;
LblProfileSlogan.Font = FontAgent.ForSize(20);
LblProfileRelationInfo.TextAlignment = UITextAlignment.Center;
LblProfileRelationInfo.Text = string.Empty;
LblProfileRelationInfo.Font = FontAgent.ForSize(15);
...
At this point we are kinda out of ideas as to what could be going wrong here and we have independently reviewed any of our code that could remotely be involved in this bug but we found nothing.
We didn't find anything related online but maybe someone else has encountered a similar issue like this in Xamarin / Xamarin iOS before?
Are there any steps we could take that we don't know of? When breaking the app in the Visual Studio for Mac debugger during the freezes the call stacks only contain native code and are not of much use.
Any help or ideas as to what else we could try are hugely appreciated :)
Edit: Adding some code
This is our BaseViewController defining some initialization methods to be used by it's children (again in 99.9% of all cases this works just fine):
public abstract class BaseViewController : UIViewController
{
public BaseViewController(string nibName, NSBundle nSBundle) : base(nibName, nSBundle)
{
ControllerDidInitialize();
}
public ClubmappViewController(IntPtr handle) : base(handle)
{
ControllerDidInitialize();
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
CustomOrientationService.ScreenRotationPortrait();
InitializeStaticContent();
Console.WriteLine("ViewDidLoad() exits just fine...");
}
public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
Console.WriteLine("When the bug occurs this never gets executed :C");
RefreshUI();
OnViewDidAppear?.Invoke(this, new EventArgs());
LoadData();
}
private protected abstract void InitializeStaticContent();
private protected abstract void RefreshUI();
private protected virtual void LoadData()
{
}
private protected virtual void ControllerDidInitialize()
{
}
}
This is the ProfileViewController that inherits from BaseViewController and that just stops being rendered or inititialized or whatever the actual problem might be (it just never shows up as described above) but most of the time it works just fine:
public partial class ProfileViewController : BaseViewController
{
public const string STORYBOARD_ID = "ProfileViewController";
public ProfileViewController(IntPtr handle) : base(handle)
{
}
private protected override void ControllerDidInitialize()
{
// do initialization things like initializing variables, etc
// no real logic here
}
private protected override void InitializeStaticContent()
{
// layouting loading
LblProfileTitle.TextAlignment = UITextAlignment.Center;
LblProfileTitle.Text = string.Empty;
LblProfileTitle.Font = FontAgent.ForSize(20);
LblProfileTitle.Font = UIFont.BoldSystemFontOfSize(20);
LblProfileName.TextAlignment = UITextAlignment.Center;
LblProfileName.Text = string.Empty;
LblProfileName.Font = FontAgent.ForSize(30);
LblProfileSlogan.TextAlignment = UITextAlignment.Center;
LblProfileSlogan.Text = string.Empty;
LblProfileSlogan.Font = FontAgent.ForSize(20);
// ... and so on ..
}
private protected override void RefreshUI()
{
// ... theme related stuff ...
ViewProfileActive.BackgroundColor = ThemeAgent.CurrentTheme.OnlineIndicatorColor;
LblProfileName.TextColor = ThemeAgent.CurrentTheme.PrimaryTextColor;
LblProfileSlogan.TextColor = ThemeAgent.CurrentTheme.SecondaryTextColor;
// ...
}
private protected async override void LoadData()
{
// load user data ...
ProfileData data = await ...
}
}
And this is the "OnClick" event that is triggered when a profile is clicked on, that's supposed to initialize and show the ProfileViewController (it's unlikely that something's wrong with this but including it nonetheless):
// ...
(sender, e) =>
{
ProfileViewController profileController = (ProfileViewController)UIStoryboard.FromName("Main", null).InstantiateViewController(ProfileViewController.STORYBOARD_ID);
profileController.ModalPresentationStyle = UIModalPresentationStyle.FullScreen;
currentViewController.NavigationController.PushViewController(profileController, true);
}
// ...

Directx device doesn't initialize for window, Program hang

I've tried following several tutorials an have seem to be having trouble.
I've got an existing program that i'm trying to add a directx window to as an additional popup forum that will run as a child to the main application form.
Here is the windows form class:
public partial class DxWindow : Form
{
Device device;
public DxWindow()
{
InitializeComponent();
initDevice();
}
private void initDevice()
{
MessageBox.Show("hello");
PresentParameters pp = new PresentParameters();
pp.Windowed = true;
pp.SwapEffect = SwapEffect.Discard;
device = new Device(0, DeviceType.Hardware, this, CreateFlags.HardwareVertexProcessing, pp);
}
private void Render()
{
//render stuff
}
private void DxWindow_Paint(object sender, PaintEventArgs e)
{
Render();
}
}
and here is where i initialize the form (from a UI button in main window)
private void toolStripButton3_Click_1(object sender, EventArgs e)
{
if (DirectxWindow == null)
{
DirectxWindow = new DxWindow();
DirectxWindow.Show();
}
}
When i run the program and click the button. it seems create the form in memory but never shows up. when i step through it in the debugger, it gets to "DirectxWindow = new DxWindow();" and then automatically jumps out of break mode and continues running with the main window frozen and no new Dxwindow().
when i break execution is seems to still be on "DirectxWindow = new DxWindow();"
Also, "MessageBox.Show("hello");" in the DxWindow constructor is never called"
Edit: I've deduced that as soon as it hits "PresentParameters pp = new Microsoft.DirectX.Direct3D.PresentParameters();" the application becomes unresponsive without throwing any errors.

Turns out my problem was needing to use
<startup useLegacyV2RuntimeActivationPolicy="true">
in the "App.config" File
Solution was found here: Mixed mode assembly is built against version 'v1.1.4322'
Although i never got the error as described by the OP. i simply had this problem as described in the comments:
"Thank you!!!! This is the weirdest problem I'd ever encountered. In VS 2012 .Net 4.0 my application would just hang the moment I initialized any variable of a type related to this DLL. I'd never seen anything like it. Couldn't find anything about the problem until I found this!" – Quinxy von Besiex

C# speech recognition (System.Speech.Recognition) issues

I've been working with a bit of speech recognition for a few days with various test programs and it's all worked fine. However i've tried implementing it into my OpenGL project and the function 'Recognized' is now not being called.
Up in the Windows Speech Recognition thing (the thing that says "try saying 'Start Listening'" an awful lot), words that are loaded appear when i say them, so I am assuming that it is correctly detecting words, it's just for some reason not triggering the event.
Here's the code i've been using. All you really need to know (besides what is shown in the code), is that AddCommands is called somewhere else, to add in a few words that i've been testing with and that 'Initiate' is called upon the loading of the form.
public class SpeechControls
{
public static SpeechRecognizer sRecognizer;
private static Dictionary<string, IVoiceControlable> controllers = new Dictionary<string, IVoiceControlable>();
public static void Initiate()
{
sRecognizer = new SpeechRecognizer();
sRecognizer.Enabled = true;
sRecognizer.SpeechRecognized += new EventHandler<SpeechRecognizedEventArgs>(Recognized);
}
private static void Recognized(object obj, SpeechRecognizedEventArgs args)
{
controllers[args.Result.Text].TriggerCommand(args.Result.Text);
}
public static void AddCommands(string[] commands, IVoiceControlable control)
{
foreach (string str in commands)
{
controllers.Add(str, control);
}
sRecognizer.LoadGrammar(new Grammar(new GrammarBuilder(new Choices(commands))));
}
}
Does anyone know why 'Recognized' would not be triggered?
Thanks for any help, much appreciated.

Because OpenGL runs of game loops rather than event listening, the thread is completely taken up by the loop. To start listening for commands a second thread is needed.

Releasing memory by the resource

I have a program in c# which uses my local webcam, to capture and store images. I have buttons to click on start,stop,continue n etc.When I run the program it works properly for the first time after I turn my system on, but in the consecutive executions of the same thing I get an error (in pop-up window):
An error occurred while capturing the video image. The video capture will now be terminated. Object reference not set to an instance of the object.
for which I assume that it might be because of the camera device, not releasing the memory it used. So how do I programatically free it up, when I click on the exit button? Below is part of the program and i get error in the webcam.start(0) method
namespace WinFormCharpWebCam
{
class WebCam
{
private WebCamCapture webcam;
private System.Windows.Forms.PictureBox _FrameImage;
private int FrameNumber = 30;
public void InitializeWebCam(ref System.Windows.Forms.PictureBox ImageControl)
{
webcam = new WebCamCapture();
webcam.FrameNumber = ((ulong)(0ul));
webcam.TimeToCapture_milliseconds = FrameNumber;
webcam.ImageCaptured += new WebCamCapture.WebCamEventHandler(webcam_ImageCaptured);
_FrameImage = ImageControl;
}
void webcam_ImageCaptured(object source, WebcamEventArgs e)
{
_FrameImage.Image = e.WebCamImage;
}
public void Start()
{
webcam.TimeToCapture_milliseconds = FrameNumber;
webcam.Start(0); //error pops up when the execution comes to this method
}
public void Stop()
{
webcam.Stop();
}
public void Continue()
{
// change the capture time frame
webcam.TimeToCapture_milliseconds = FrameNumber;
// resume the video capture from the stop
webcam.Start(this.webcam.FrameNumber);
}
public void ResolutionSetting()
{
webcam.Config();
}
public void AdvanceSetting()
{
webcam.Config2();
}
}
}

You have a NullReferenceException thrown, not OutOfMemoryException.
Check your call stack to pinpoint where it originates. You can debug your app with debugger set to break on exception thrown, so it will break right where your exception occurs (press CRTL+D, E to open exceptions window in VS.NET).

From the error you are getting, I am guessing you downloaded the EasyWebCam Library.
If that is correct then here's how I worked around it:
1. I installed the Cyberlink's Youcam software on my machine.
2. Whenever I start my own application, the EasyWebCam library detects the Youcam WebSplitter on machine and prompts me to select either that or the default webcam driver.
3. I select the YouCam WebSplitter and the app works fine with it.
At this point, there comes along another snag: the Youcam process doesn't terminate when my application closes.
How I fixed it?
I had to get the Youcam process and Kill() it when my application window's about to exit.
This ugly solution worked.