Develop Reference

When is taking a photo done?

I'm working on a wp8-app that takes a photo and then takes you to the next screen to decide whether you like it or not.
The current approach was this:
private void ShutterButton_Click(object sender, RoutedEventArgs e)
{
if (cam != null)
{
try
{
cam.CaptureImage();
await Task.Delay(1500);
NavigateFront();
}
catch (Exception ex)
{
...
}
}
}
public void NavigateFront()
{
string naviString = "/confirmPicture.xaml?parameter=" + fileName.ToString();
_rootFrame.Navigate(new Uri(naviString, UriKind.Relative));
}
On my Lumia 520 it crashed sometimes. If I increase the wait-time to 2,5sec it works. But of course this should not be the way to do it.
If I catch the void cam_CaptureImageAvailable(object sender, Microsoft.Devices.ContentReadyEventArgs e)-Event and try to navigate after everything is done and all streams are closed I still get in a NavigateFailed-State and the app crashes.
My question is: is there any other useful event that ensures that all work is done and I can navigate without using static time-based values?

Navigation with a PhotoCamera is possible, just subscribe to its CaptureCompleted event handler
cam.CaptureCompleted += new EventHandler<CameraOperationCompletedEventArgs>(camera_CaptureCompleted);
and this would be the event
void camera_CaptureCompleted(object sender, CameraOperationCompletedEventArgs e)
{
try
{
Deployment.Current.Dispatcher.BeginInvoke(delegate()
{
try
{
cam.Dispose();
NavigationService.Navigate(new Uri("URI nething", UriKind.Relative));
}
catch (Exception)
{
MessageBox.Show("Problem occured!!");
}
});
}
catch
{
MessageBox.Show("Problem in camer_capturecompleted");
}
}
I did it in one of my apps targeting windows phone 7. Check if this works for you as well.

WP7 Text-To-Speech Playing Whole Collection At Once

I working on a Windows Phone 7 app with Text-To-Speech capabilities. I'm using Text-To-Speech with Microsoft Translator Service and the following C# code...
// Text-To-Speech with Microsoft Translator Service (http://translatorservice.codeplex.com/)
private void TextToSpeech_Play(object sender, EventArgs e)
{
SpeechSynthesizer speech = new SpeechSynthesizer(CLIENT_ID, CLIENT_SECRET);
//string content = "This is a beautiful day!";
string language = "en";
//speech.SpeakAsync(content, language);
foreach (UIElement element in todayschapter.Children)
{
if (element is TextBlock)
{
string content = (element as TextBlock).Text;
speech.SpeakAsync(content, language);
}
}
}
In this instance, todayschapter is a StackPanel and its Children are TextBlocks. I'm wanting to simply play audio of each TextBlock, in succession. The problem is that it is play the audio of EVERY TextBlock at the same time.
I have a sneaking suspicion that the problem is SpeakAsync(), but I'm not sure. The documentation shows Speak(), but that isn't available (maybe a different version) in the Visual Studio methods helper dropdown (little thing that shows as you type - not sure what it's called).
Is there a way to make it wait for each play to finish before playing the next? Is foreach not the right choice, for this?
As always, if my code just looks stupid, please recommend better ways. I'm very much a beginner programmer.

Just use the Speak instead of the async call, since you want to have it one after another anyway.

The SpeakAsync call is indeed the problem. Unfortunately, since SpeakAsync doesn't return a Task, you can't just convert this to await SpeakAsync() (which would be the most straightforward conversion).
And, looking at the source code, it doesn't fire an event to tell when it's done. So let's add one (in SpeechSynthesizer.cs):
public event EventHandler<SpeechEventArgs> SpeakCompleted;
public void SpeakAsync(string text, string language)
{
this.GetSpeakStreamAsyncHelper(text, language, result =>
{
if (result.Error == null)
{
SoundEffect effect = SoundEffect.FromStream(result.Stream);
FrameworkDispatcher.Update();
effect.Play();
this.OnSpeakCompleted(new SpeechEventArgs(result.Error)); // added to call completion handler
}
else
{
this.OnSpeakFailed(new SpeechEventArgs(result.Error));
}
});
}
// new function
private void OnSpeakCompleted(SpeechEventArgs e)
{
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
if (SpeakCompleted != null)
SpeakCompleted(this, e);
});
}
Now, you'll need to handle the SpeakCompleted event and start speaking the next string.
Something like this (I haven't even compiled this, so be warned):
private Queue<string> utterances;
private SpeechSynthesizer speech;
private void TextToSpeech_Play(object sender, EventArgs e)
{
speech = new SpeechSynthesizer(CLIENT_ID, CLIENT_SECRET);
speech.SpeechCompleted += new EventHandler<SpeechEventArgs>(TextToSpeech_Completed);
foreach (UIElement element in todayschapter.Children)
{
if (element is TextBlock)
{
string content = (element as TextBlock).Text;
utterances.Enqueue(content);
}
}
TextToSpeech_Completed(null, null); // start speaking the first one
}
private void TextToSpeech_Completed(object sender, SpeechEventArgs e)
{
if (utterances.Any())
{
string contents = utterances.Dequeue();
speech.SpeakAsync(contents);
}
}

Kinect New Window Wpf

So I'm making a Kinect application using buttons, and to navigate the app, I'm making new windows for each button. I'm come across an issue I haven't been able to find any help at all on, and would appreciate any help.
So to open the new window, I'm using this:
private void button1_Click(object sender, RoutedEventArgs e)
{
//SUPPOSED to uninitialize the Kinect
UninitializeKinectSensor(this.Kinect;
//To open the new window
Window1 newwindow = new Window1();
newwindow.Show();
//To close the first window...
Close();
{
SO that one line is supposed to uninitialize the Kinect so it'll be free for the new window to use, but when it goes to the new window, the Kinect freezes. If I use the mouse to go back to the first window, it works on the first window again, which it shouldn't.
I also added in this line in the initialization phase
public Window1()
{
//Other init code is here, but this is the line I added. It doesn't seem to do anything.
InitializeKinectSensor(this.Kinect);
}
Any help is greatly appreciated!! I'm sure it's something simple and I just failed miserably haha XD

Do you really have to create a new window instead of using pages?
In your MainWindow you create a frame that takes all the window and use this frame to navigate between pages. This way, you'll keep the focus of the kinect in your whole application.

Depends alot on what UninitializeKinectSensor is actually doing. Just as a quick fix, though, you can try calling uninitialize on a background worker and see if that helps at all.

Instead of using the "Show()" use "ShowDialog()".It's better if you can create a static class or method to initialize and uninitialized kinect.
public static void start()
{
KinectSensor.KinectSensors.StatusChanged += kinectSensorsStatusChanged;
DiscoverSensor();
}
private static void kinectSensorsStatusChanged(object sender, StatusChangedEventArgs e)
{
KinectSensor oldSensor = Kinect;
if (oldSensor != null)
{
UninitializeKinect();
}
var status = e.Status;
if (Kinect == null)
{
//updateStatus(status);
if (e.Status == KinectStatus.Connected)
{
Kinect = e.Sensor;
DiscoverSensor();
}
}
else
{
if (Kinect == e.Sensor)
{
//updateStatus(status);
if (e.Status == KinectStatus.Disconnected ||
e.Status == KinectStatus.NotPowered)
{
Kinect = null;
sensorConflict = false;
DiscoverSensor();
}
}
}
}
private static DispatcherTimer readyTimer;
private static void UninitializeKinect()
{
if (speechRecognizer != null && Kinect != null)
{
Kinect.AudioSource.Stop();
Kinect.SkeletonFrameReady -= kinect_SkeletonFrameReady;
Kinect.SkeletonStream.Disable();
Kinect.Stop();
//this.FrameSkeletons = null;
speechRecognizer.RecognizeAsyncCancel();
speechRecognizer.RecognizeAsyncStop();
}
if (readyTimer != null)
{
readyTimer.Stop();
readyTimer = null;
}
}

Pause Kinect Camera - Possible error in SDK reguarding event handler

I'm in the process of converting my Microsoft SDK Beta code to the Microsoft SDK Official Release that was released February 2012.
I added a generic PauseKinect() to pause the Kinect. My pause will really only remove the event handler that updated the image
Pros:
No Reinitialization (30+ second wait time)
Cons:
Kinect still processing images
Pause Method (Color Only)
internal void PauseColorImage(bool isPaused)
{
if (isPaused)
{
_Kinect.ColorFrameReady -= ColorFrameReadyEventHandler;
//_Kinect.ColorStream.Disable();
}
else
{
_Kinect.ColorFrameReady += ColorFrameReadyEventHandler;
//_Kinect.ColorStream.Enable(ColorImageFormat.RgbResolution640x480Fps30);
}
}
PROBLEM:
Even though I'm removing the event why is it still getting triggered?
NOTE:
Also when I pause the color image I'm also pausing the depth and skeleton in their object.
SIDE NOTE:
If I uncomment my code it works fine, but then it'll take forever to reinitialize which is not what I want to do.
MS in Reflector
public void AddHandler(EventHandler<T> originalHandler)
{
if (originalHandler != null)
{
this._actualHandlers.Add(new ContextHandlerPair<T, T>(originalHandler, SynchronizationContext.Current));
}
}
public void RemoveHandler(EventHandler<T> originalHandler)
{
SynchronizationContext current = SynchronizationContext.Current;
ContextHandlerPair<T, T> item = null;
foreach (ContextHandlerPair<T, T> pair2 in this._actualHandlers)
{
EventHandler<T> handler = pair2.Handler;
SynchronizationContext context = pair2.Context;
if ((current == context) && (handler == originalHandler))
{
item = pair2;
break;
}
}
if (item != null)
{
this._actualHandlers.Remove(item);
}
}
public void Invoke(object sender, T e)
{
if (this.HasHandlers)
{
ContextHandlerPair<T, T>[] array = new ContextHandlerPair<T, T>[this._actualHandlers.Count];
this._actualHandlers.CopyTo(array);
foreach (ContextHandlerPair<T, T> pair in array)
{
EventHandler<T> handler = pair.Handler;
SynchronizationContext context = pair.Context;
if (context == null)
{
handler(sender, e);
}
else if (this._method == ContextSynchronizationMethod<T>.Post)
{
context.Post(new SendOrPostCallback(this.SendOrPostDelegate), new ContextEventHandlerArgsWrapper<T, T>(handler, sender, e));
}
else if (this._method == ContextSynchronizationMethod<T>.Send)
{
context.Send(new SendOrPostCallback(this.SendOrPostDelegate), new ContextEventHandlerArgsWrapper<T, T>(handler, sender, e));
}
}
}
}

After posting an identical question on the Microsoft forum and talking to multiple Microsoft representatives they basically said the only way to do a "pause" is to enable/disable the streams (uncomment my comments). Without saying it straight forward its a bug in the SDK. They are going to talk to the people in the development team and try to fix the issue in future releases.
EDIT
In the May 2012 Release it is STILL not fixed. Thanks Microsoft!

Disposed Forms with a Base and threading returns null for progress bar

I have a base form that I use when calling 2 forms. Previously when calling the forms I didn't dispose of them, but I have found that reusing them, they would stay in memory and not get collected. So I have instead used a using statement instead to clear the memory, and all my problem are fixed.
But now a new problem arises, one that I had previously when testing my app with mono on Linux. I though it might be a mono specific problem, but since adding the using statement the same thing happens on my Windows machine. So it might just be that the Garbage Collector on Mono is different and was disposing properly of my forms.
Here is my problem I have a thread that I start to extract files in the background And I have progress bar telling me the progress, before using the dispose if I closed the form and reopened it my files extracted correctly and the progress bar was working fine. But now they work fine the first time, but if I reopen the form or the other one that has the same base, the extraction is not working, no files are extracted because I have a null exception when reporting the progress.
private void ExtractFiles()
{
Zip.ExtractProgress += new EventHandler<ExtractProgressArgs>(Utils_ExtractProgress);
Thread t = new Thread(new ThreadStart(Zip.ExtractZip));
t.IsBackground = true;
t.Start();
FilesExtracted = true;
}
void Utils_ExtractProgress(object sender, ExtractProgressArgs e)
{
UpdateProgress(e.Pourcentage);
}
private delegate void UpdateProgressDelegate(int Pourc);
private void UpdateProgress(int Pourc)
{
lock (this)
{
if (Progress.ProgressBar.InvokeRequired)
{
UpdateProgressDelegate del = new UpdateProgressDelegate(UpdateProgress);
Progress.ProgressBar.BeginInvoke(del, Pourc);
} else
{
Progress.Value = Pourc;
}
}
}
This code is in my BaseForm, the Progress control isn't null, but all of it's properties have null exceptions. So when checking if Invoked is required it raises an Null exception.
Here is my Zip.Extract method
public static event EventHandler<ExtractProgressArgs> ExtractProgress;
static ExtractProgressArgs Progress;
internal static void ExtractZip()
{
try
{
using (ZipFile zip = ZipFile.Read(Variables.Filename))
{
Progress = new ExtractProgressArgs();
Progress.TotalToTransfer = Convert.ToInt32(zip.Sum(e => e.UncompressedSize));
zip.ExtractProgress += new EventHandler<ExtractProgressEventArgs>(zip_ExtractProgress);
Old = 0; New = 0;
foreach (ZipEntry item in zip)
{
item.Extract(Variables.TempFolder, ExtractExistingFileAction.OverwriteSilently);
}
}
} catch (Exception)
{
}
}
static long Old;
static long New;
static void zip_ExtractProgress(object sender, ExtractProgressEventArgs e)
{
if (e.EventType == ZipProgressEventType.Extracting_EntryBytesWritten)
{
New = e.BytesTransferred;
Progress.Transferred += New - Old;
Old = e.BytesTransferred;
if (ExtractProgress != null)
{
ExtractProgress(e.CurrentEntry, Progress);
}
} else if (e.EventType == ZipProgressEventType.Extracting_AfterExtractEntry)
{
Old = 0;
}
}
Might be because my Zip.Extract is static? I have almost no knowledge of multi-threading, like synchronization, etc.

The short answer is yes, some of your problems are due to the static nature of those operations.
You should be able to resolve the problem by removing the static declarations from your Zip class and then creating an instance of it as needed.