I'm new to J2ME, in lots of places I have seen this: Display.getInstance().callSerially..
e.g.
Display.getInstance().callSerially(new Runnable() {
public void run() {
startThread();
}
});
why we need to use this?what is the advantage?please anyone explain me..
Did you try reading the lengthy explanations in the javadoc-api?
There are several paragraphs in the javax.microedition.lcdui.Display#callSerially(java.lang.Runnable) apidoc and even a code sample explaining why and how this is to be used
Related
I try to call ShowDialogAsync in a synchron code. I'm not very familiar with async programming. If I run this code, I end up in a deadlock. If I change Command to TaskCommand, it will work, but I have to change all Code to async.
public MainWindow()
{
InitializeComponent();
Abc = new Command(() => Asd());
}
public Command Abc { get; set; }
private void Asd()
{
var b = StartDialog(true).GetAwaiter().GetResult();
}
private async Task<bool> StartDialog(bool isMultiple)
{
await ServiceLocator.Default.ResolveType<IUIVisualizerService>().ShowDialogAsync<PersonVm>(new PersonM());
return true;
}
Here I have used the answer from here.
Could someone help me please?
The recommended way is to migrate your code to async. Most features in Catel are async (such as vm initialization, etc). At first it might be a bit overwhelming, but once you get how it works, it's a very convenient way of programming. In the meantime, you can use a workaround (this is not best practice, but will get you through this task):
private async void Asd()
{
var b = await StartDialog(true);
}
Note that async void is not recommended and should really be avoided unless no other options are available (such as non-async event handlers, etc).
My C# app has lots of forms to perform various tasks. To keep things simple, I have a static class FormsCollection where the instances of each of the other forms are kept, so that they are shown and hidden from one place.
Now i was getting that classic debug time "Cross-thread" error. I tried to fix it the following way:
public class FormsCollection : Control // inherited from Control only to be
// able to call "this.Invoke"
{
public delegate void ShowFormDelegate(Form form);
public static Main mainForm;
// and many other forms...
public void ShowForm(Form form)
{
if (form.InvokeRequired)
{
ShowFormDelegate delegateFunc = new ShowFormDelegate(ShowForm);
this.Invoke(delegateFunc, new object[] { form });
}
else
{
previousForm = currentForm;
currentForm.Hide();
currentForm = form;
currentForm.Show();
}
}
}
Inside the user/caller forms, i simply make an object of FormsCollection and call the ShowForm method (almost a 100 such calls):
FormsCollection f = new FormsCollection();
f.ShowForm(FormsCollection.mainForm);
And after all this ordeal, what i get is that the same error appears at the very same spot as before! What an irony! :)
What am i doing wrong? Please help me out....
I got extremely hard-to-find answer to this problem from this slightly irrelevant page. Following is the updated code for any struggling programmers looking for a work around to this problem:
public void Show(Form nextForm)
{
Thread thread = new Thread(
new ThreadStart(() =>
{
PreviousForm.BeginInvoke(
new Action(() =>
{
PreviousForm = CurrentForm;
CurrentForm = nextForm;
PreviousForm.Hide();
CurrentForm.Show();
}
));
}
));
thread.Start();
}
This seems to have resolved the cross-thread problem that i was facing despite several work-arounds. It is working as yet without raising any exceptions and I have tested almost all the scenarios of my app going back and forth from form to form.
I need to pass an object with some information to consume in my Background Task. I try to search in web but not found any solution. It is possible?
One workarround is save information what I need to pass in isolated storage in my MainProjet and in my BackgroundTask project consume information saved before. But this solution is not beautiful to use.
Someone help me?
Thanks in advance
You can use SendMessageToBackground method
var message = new ValueSet();
message.Add("key",value);
BackgroundMediaPlayer.SendMessageToBackground(message);
In background task listen to this method
public void Run(IBackgroundTaskInstance taskInstance)
{
BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
}
private void BackgroundMediaPlayer_MessageReceivedFromForeground(object sender, MediaPlayerDataReceivedEventArgs e)
{
foreach (string key in e.Data.Keys)
{
switch (key.ToLower())
{
}
}
}
I am not able to define a [BeforeFeature]/[AfterFeature] hook for my feature file. The application under test is WPF standalone desktop applications.
If I use [BeforeScenario]/[AfterScenario] everything works fine, the application starts without any problem, the designed steps are performed correctly and the app is closed.
Once I use the same steps with [BeforeFeature]/[AfterFeature] tags the application starts and the test fails with:
The following error occurred when this process was started: Object reference not set to an instance of an object.
Here is an example:
[Binding]
public class Setup
{
[BeforeScenario("setup_scenario")]
public static void BeforeAppScenario()
{
UILoader.General.StartApplication();
}
[AfterScenario("setup_scenario")]
public static void AfterAppScenario()
{
UILoader.General.CloseApplication();
}
[BeforeFeature("setup_feature")]
public static void BeforeAppFeature()
{
UILoader.General.StartApplication();
}
[AfterFeature("setup_feature")]
public static void AfterAppFeature()
{
UILoader.General.CloseApplication();
}
}
StartApplication/CloseApplication were recorded and auto-generated with Coded UI Test Builder:
public void StartApplication()
{
// Launch '%ProgramFiles%\...
ApplicationUnderTest Application = ApplicationUnderTest.Launch(this.StartApplicationParams.ExePath, this.StartApplicationParams.AlternateExePath);
}
public class StartApplicationParams
{
public string ExePath = "C:\\Program Files..."
public string AlternateExePath = "%ProgramFiles%\\..."
}
Noteworthy: I'm quite new with SpecFlow.
I can't figure it out why my test fails with [BeforeFeature] and works fine with [BeforeScenario].
It would be great if somebody could help me with this issue. Thanks!
I ran into a similar problem recently. Not sure if this can still help you, but it may be of use for people who stumble upon this question.
For BeforeFeature\AfterFeature to work, the feature itself needs to be tagged, tagging just specific scenarios will not work.
Your feature files should start like this:
#setup_feature
Feature: Name Of Your Feature
#setup_scenario
Scenario: ...
Hi guys I tried to play a song and print its metadata using java fx 2.1 api using the following code
Media media = new Media(UIandControls.class.getResource("/assets/testData/mom.mp3").toExternalForm());
MediaPlayer mediaPlayer = new MediaPlayer(media);
ObservableMap list=media.getMetadata();
System.out.print(list);
mediaPlayer.play();
for some reason getMetadata() is empty observable Map.
Output looks like this
{}
plz help me.. Thank you.
Need to call mediaPlayer.play() before retrieving metadata.
I had troubles with this at first but I found that using this worked.
mediaPlayer.getMedia().getMetadata().addListener(new MapChangeListener<String, Object>(){
#Override
public void onChanged(Change<? extends String, ?> change) {
if(change.wasAdded()){
if(change.getKey().equals("artist"))
setArtist(change.getValueAdded().toString());
else if(change.getKey().equals("title"))
setTitle(change.getValueAdded().toString());
else if(change.getKey().equals("year"))
setYear(change.getValueAdded().toString());
}
}
});
Also I read that the media data won't always be there right after initialization, therefore calling the mediaPlayer.setOnReady() method can make sure that the data is there.
Example:
mediaPlayer.setOnReady(new Runnable(){
#Override
public void run() {
setTrackLength(mediaPlayer.getMedia().getDuration().toMinutes());
mediaPlayer.currentTimeProperty().addListener(progressChangeListener);
}
});