Dart Timer Seemingly Doesn't Fire - timer

For some reason, the timer I made in Dart seems to not fire, as it doesn't change the screen contents. I had it working at one point, but it was gradually getting faster and faster for some reason (ticking more times per second, every second it ticked,) and I had to work on it.
Here's a link to the main.dart file.
Can anyone explain what I did wrong here? My placement of the tick function, perhaps?

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Is there a way to refresh the page as many times as possible and wait for an element to load in that page in selenium?

I need to check if an element is appearing after refreshing a page continuously, cause it takes a while for the changes to be reflected and the element to appear in that page.
Is there any built in method in selenium using Ruby as the programming language ?
Just to confirm, it sounds like the page does not dynamically update once the content is available, so you have to wait until that is true, and then manual refresh, right?
I don't know of anything built into selenium to handle this. It feels like it might even be a symptom of a UI that needs a little more design work (pardon my critique). If the user is experiencing the same thing as the test -- kicking off an action, waiting some unspecified period of time, and then manually refreshing to see the results -- that's a kind of lousy user experience. If that's a bad assumption, and there IS feedback (e.g. a spinner), then your best option will be to conditionally wait for the spinner to appear and then disappear, and then refresh a single time.
If there's really no visible feedback, then you still have a couple of options:
Easy: Hardcode a sleep that's longer than the operation will ever take to complete, and refresh once.
Medium: In a loop, sleep for a constant delay, refresh, repeat until some timeout.
Hard: If the delay required varies widely (sometimes seconds, sometimes minutes), you might consider an exponential back off solution, that sleeps for increasingly longer delays each iteration, before ultimately timing out. The upside is that you're not frantically refreshing dozens of times, the downside is that your delay might be unnecessarily long, if the content arrives just after the next big delay begins.
You can use wait method for the element to be available.
If you need to refresh the page continuously just make sure to wait after each refresh.

How can I optimize Robot Framework to speed up testing of an Angular application?

I know the basics of optimizing Robot Framework for speed on normal applications, but this is not a normal application. It's not a question of going as fast as possible, because if the code executes too fast on an Angular application, it'll try to click an element that isn't enabled or visible, or an element that doesn't exist yet. Timing issues abound, and the result is that I'm using a keyword (below) to slow down my program universally. The problem is that it's hard-coded, and I'm looking for a more "programatic" (programatical? I don't know the exact term) solution that will wait for an element to be clickable and then click it as soon as it is.
This is the keyword I use after every single click (${SLOW_TIME} is a global variable set to 0.5s):
Slow Down
# EXAMPLE USAGE
# Slow Down ${SLOW_TIME}
[Arguments] ${SLOW_TIME}
Sleep ${SLOW_TIME}
This is my current solution, which was written to verify that an element is ready to be clicked for test verification purposes, not speed. It's not complete (needs "Is Clickable") and occasionally causes the program to wait longer than it has to:
Verify Element Is Ready
# EXAMPLE USAGE
# Verify Element Is Ready id=myElementId
# Click Element id=myElementId
[Arguments] ${element}
Variable should exist ${element}
Wait until element is visible ${element}
Wait until element is enabled ${element}
I'm aware that Robot Framework isn't built for speed, but for long tests I'm tired of doing nothing for 10 minutes waiting for it to finish, only to see that I have an incorrect [Fail]. If the solution involves Python, Javascript, or Java, I can work that in.
EDIT: I'm currently using ExtendedSelenium2Library, but its implicit waits don't always work, so I wanted a second layer of waiting, but only as long as necessary.
First solution to explore would be to use libraries specifically designed for Angular based web applications, such as AngularJsLibrary or ExtendedSelenium2Library. As far as I know, ExtendedSelenium2Library is the one that works best (but perhaps not without any issues, I think it does have a few issues)
Next thing to know is, given that your element indeed is visible, it doesn't necessarily mean that it's ready to be clicked. There are quite a few ways to get around this kind of issues.
One way is to put a sleep in your test setup, to give the page some time to fully initialize. I'm personally not a fan of this solution. This solution also doesn't work well for pages that load new content dynamically after the initial document was initialized.
Another way is to wrap your click element in a wait, either by writing your own in Python or, using something like Wait Until Keyword Succeeds

Corona / Lua / frustrating timer multiplication

I am in the process of building a mobile game with Corona SDK, which is based on Lua. Until now i didn't need any help but this time I can't seem to find the cause, and I've been searching for it for hours.
It's one of those timer problems, where, after leaving, removing, and revisiting the scene, items that are spawned within a loop just multiply themselves every relaunch. More specificly, everytime a "forbidden" collision happens, which leads to the relaunch, according to my onCollision function.
What I already corrected after hours of strenuous research :
--the code inside the onCollision function is now inside the "began" phase,
so that can't cause the multiplication
--the scene phases are also correctly used
--transitions and timers are all canceled right before the relaunch
Since the code would be too long for you to look through, I'd rather ask for some hints :
What do you have in mind can cause such problems, besides what I already mentioned.
I appreciate every answer! Thanks alot.
The above comments are valid, it is going to be hard to diagnose the problem without being able to look at the code.
In the past, I have found it very helpful to name all my objects when dealing with collisions, so when a collision happens I know what objects caused it and it is very helpful for debugging purposes.
It looks like you have an issue with how you are starting the scene and deallocating resources when the scene ends. You may want to start/stop physics when the scene leaves and comes back, but without code I can't give a concrete answer.

GTK3 sometimes ignores gtk_widget_queue_draw when repeated too quickly?

I have an application which does some simulation, and renders the result. Because the render can sometimes be very slow, I separated it into another thread, and the main thread calls gtk_widget_queue_draw once it's ready. If it's not finished drawing yet, the extra requests get discarded (since queue_draw only invalidates it, and it's impossible to be "more" invalid).
The result is that with large complicated systems, simulation maxes out a thread, and render maxes out another thread, and everything works.
I just ran into a different problem, and I don't see why it's happening: A sufficiently simple simulation and render (6 5-point lines) causes it to break.
The first few (I've seen everywhere from around 60 to 400) steps render fine (in a fraction of a second), until one step renders twice. After that, it ignores the queue_draw, until I do something like drag a window over the render window, after which it restarts (until it breaks again).
If I artificially slow down the requests (usleep(10000) is around enough), this does not happen.
This is a completely unacceptable solution however, because the process of displaying is not allowed to interfere with the normal simulation thread (No delays, no mutexes, etc. etc.). I need a solution that makes the render thread do "as well as possible", given that it is working with volatile data. It does not have to be perfectly accurate--I really don't care if a frame renders a little wrong (half of frame i, half of i+1 is fine), as long as it does render.
Why is this happening, and how do I fix it?
You are having a race condition.
Since GTK3.6, you need to call gtk_widget_queue_draw like this:
g_idle_add((GSourceFunc)gtk_widget_queue_draw,(void*)window);
or like this:
gdk_threads_add_idle((GSourceFunc)gtk_widget_queue_draw,(void*)window);
where window is the GtkWidget* you want to draw.
Use the gdk_threads_add_idle if you're not sure whether libraries or code used by your app use the deprecated (since 3.6) gdk_threads_enter and gdk_threads_leave functions.
See: https://developer.gnome.org/gdk3/stable/gdk3-Threads.html#gdk3-Threads.description
Before GTK3.6, gdk_threads_enter and gdk_threads_leave had to be used to acquire the lock for GTK calls.
Did you locked UI calls in the threads with gdk_threads_enter/gdk_threads_leave ?
Maybe adding a code sample would help too...

Update loop in windows forms?

I've been working with some game engines lately. They all have an Update() function that gets called every frame (not a loop in the strict sense of the word, but you get the idea). Any code you want to execute needs to be placed in here.
This made me wonder, how does this work in windows forms, as the only thing I use there is events?
(If the title doesn't explain it good enough, feel free to change it)
It basically works the same, it is only called the message loop, event loop or message pump
http://msdn.microsoft.com/en-us/library/aa383738.aspx

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