I am trying to run a simple while loop to demonstrate to some pupils. The exercise is to be able to put numbers into a text box, press a button and the running total is shown in a label. The loop would be broken if the user put in the number 999. Below is my current attempt. The program will load but when the button is pressed nothing happens. Sigh!
Below is my current attempt.
- (IBAction)btnCalculate:(id)sender
{
int Total, Number;
Total = 0;
Number= 0;
while (Number!=999)
{
Number = [self.txtNumber.text integerValue];
Total = Total + Number;
self.lblTotal.text= [NSString stringWithFormat:#"%d",Total];
}
}
What do you expect to happen?
I think the loop is blocking your main thread, so you don't see everything happen and cannot change the labels text.
I think for your purpose it would be better to read the number from the label and increase total until it has the value of number.
NSInteger number = [self.txtNumber.text integerValue];
while(total <= number) {
NSLog("%d", total++);
}
If you want to put it in lblTotal you should run the loop on a background thread, but make sure to update your lbltotal.test on the main thread.
looks like an infinite loop to me. The method is likely called when you click the button, and the integer value you get doesn't change in subsequent loop iterations (because you don't allow the UI thread to continue to do its thing). You'll need to move the state out into properties on the object. This is not like reading input from stdin. The execution flow should go through the entire OS event loop, and your while loop is not at all part of that. So if the first value you enter is not 999, you get stuck in the while loop and the value you get after subsequent iterations in the while loop does not change (because your while loop is the only thing running on the UI thread and it's blocking further interactivity).
Really, you need to think about the flow of control. it's not at all like a standard terminal input / output model.
Related
I am writing an application to update the numeric value given user's input value and depending on the user's input value the program checks if it is greater than 10 if it is greater than 10 then the program waits for 1 second and then will have a popup message says "true".
My intention was to call the conditional check, printing true every one second if the user's input value is greater than 10; in other words, the case structure was to be called regardless of the event structure in the same loop infinitely.
But it doesn't seem to work the way I expected. Unless there is user's new input value, getting into the event structure, the program doesn't get to the case structure even though the case structure is in a loop.
Is there any way to call the case structure not dependent to the event structure but I want to use a shift register for the numerical value and also having an event structure and a case structure in parallel.
Thanks.
You've created an Event Structure that handles the Value Change input for your numeric control, so that will do exactly what it says: wait for a Value Change event to happen. When that event is received, the code in its Event Structure frame will execute and then the Event Structure will exit.
It looks as if you've wired a value from the shift register to the timeout terminal of the Event Structure, so I assume you must also have created a Timeout event case? If so, the event structure should stop waiting after the number of milliseconds wired to the timeout terminal.
The value you check in order to decide whether to show your true message is the value that was passed in to the shift register on the previous loop iteration. If the control value changes, that comes from the NewVal terminal in the Value Changed event case. But where does it come from in the timeout case? It looks to me as if you haven't wired it in that case, because the terminal coming out of the event structure has a little dot in it instead of being solid orange. That means you will get a default value for any case where the terminal wasn't wired. The default value for numerics is zero. So if the event structure times out, the value going in to the shift register is zero, you get zero out of the shift register on the next iteration, zero is not greater than 10, so you don't see the message again.
I don't understand what you're trying to do in the event case where you've wired the NewVal terminal to a Value property node of the same control. Can you explain what that is supposed to achieve?
Your question reads as if this is a programming exercise where you have to use these specific LabVIEW structures, so rather than suggest better ways of achieving what you say you want this code to do, I'll leave it to you to decide how to change it. In the meantime though I do recommend re-reading the Event Structure help and the caveats and recommendations it links to.
I desperately need help with a game I am making. For a bit of context, i am making a memory game and i have the following piece of code that is being troublesome. I have a bunch of labels on the form, 16 to be exact, with 1 randomly generated symbol placed in each. Each symbol appears in the labels twice.
------------------------------Continued----------------------------------------
'MsgBox("hello") 'used to check if the second inccorect press shows up - it does show but instantly changes colour
'''''''''''''''''NEED SOME CODE THAT PAUSES IT HERE'''''''''''''''
labels(0).ForeColor = Color.DarkRed
sender.ForeColor = Color.DarkRed
End If
flips = 1
End If
End If
tmrmemory.Enabled = True ' starts the timer after the user clicks the first label
End Sub
What's supposed to happen is that when the labels clicked don't match, it should show both the clicked labels for a short period before changing them both back to "DarkRed" which is the colour of the form's background.
I have tried using a timer but then i can't use sender.forecolor=color.darkred because it is not declared globally.
I have also tried using the command Threading.Thread.Sleep(500) but it still doesn't show the second incorrect click. I know that the code i have used works because when i use the message box, i can see both symbols and when the two clicks are correct, it stays.
Threading.Thread.Sleep(500) will actually pause your code for half a second. However during this time it won't do anything, not even refresh your controls. To get the effect you want, you need to call the YourControl.Refresh method before calling Threading.Thread.Sleep to force the control to redraw immediately.
On a side note, I would advise you not to call Threading.Thread.Sleep on UI thread. It will give a feeling of program hang. Instead do your work on a separate thread. You can either do all the work yourself right from creating a separate thread to destroying it, or use the BackgroundWorker control which has all the functionality built in.
Here is the link to an article I wrote a long time ago regarding BackgroundWorker that might be useful for you:
http://www.vbforums.com/showthread.php?680130-Correct-way-to-use-the-BackgroundWorker
Declare a variable outside the sub that stores what label should be flipped when the timer ends.
Label click sets
storedLabel = sender
Timer tick sets storedLabel.ForeColor = Color.DarkRed
I am using the .isPressedIn() function see if the mouse click is in a target shape. However, whenever you click on the target shape, it will say the response is incorrect. However, whenever you hold the mouse button down in the target shape, it will say the mouse was clicked on the target. I'm not sure how to fix the mouse button release. I tried using CustomMouse, but I am unable to get that to click inside a shape (unless I am mistaken). Any suggestions would be greatly appreciated.
Thanks!
stimDuration = 5 #stimuli are on the screen for 5 seconds
potential_target = [shape1, shape2, shape3] #shapes that may be a target
target = random.sample(potential_target, 1) #randomly select a target
myMouse = event.Mouse() #define mouse
if clock.getTime() >= stimDuration
ResponsePrompt.draw() #message to indicate to participant to select target
win.flip()
core.wait(2)
if myMouse.isPressedIn(target[0]):
print "correct"
else:
print "incorrect"
The problem is that the line myMouse.isPressedIn(target[0]) checks the state of the mouse exactly when that line is run. Since it is preceeded by a core.wait(2) it does not react to mouse clicks in those two seconds and consequently only collects the mouse response of you still hold it down after two seconds.
I would instead have a tight loop around the myMouse.isPressedIn which runs thousands of times per second. So skipping your first lines:
ResponsePrompt.draw() # message to indicate to participant to select target
win.flip() # show that message
while True: # keep looping. We will break this loop on a mouse press
if myMouse.isPressedIn(target[0]): # check if click is within shape
print "correct"
break # break loop if this condition was met
elif myMouse.getPressed(): # check if there was any mouse press at all, no matter location
print "incorrect"
break # break while loop if this condition was met
In that code, you are using the expression if myMouse.isPressedIn(target[0]), but are only evaluating that expression after some time has elapsed (stimDuration). This means that isPressedIn() will be typically be evaluated well after the actual click happened. At that point, the mouse may no longer be within target[0], or may not longer be being pressed down by the subject. So I think what you are seeing is the correct (expected) behavior.
So to obtain the behavior that you want, you need to do keep track of whether then mouse was pressed in the shape on every frame.
Also, I am not sure how you are using the code you posted. Some looks appropriate for every frame, but some looks like it should be run only once (Begin routine). You might want to review that--things should not be initialized every frame (like target or myMouse).
Is there a way to know that an agent in running in debug mode (Tools/Debug LotusScript has been activated) ?
I found nothing in NotesAgent class, something like RunOnServer but RunInDebugger.
I need this to avoid using the progress bar function located in NNOTESWS.DLL, which pops over the debugger and prohib any click (step into, or watching variables). BTW if it occurs to someone you still can press F8 / F5, this help at least not to kill Notes.
There Is a very good example for doing this in OpenNTF. You can find it here.
And in fact it IS for the progress bar, so you can use tho whole class from there.
The trick is: you add a function with a stop statement. You measure the time before the stop statement and after. If the time passed is bigger than 100ms, than a user had to click on "continue", what he never manages to do in such a small amount of time. If debugger is not enabled, the stop is ignored - no delay...
Here is the function used in the linked openntf article:
Public Function IsDebugMode() As Boolean
Dim start As Variant
start = Getthreadinfo(6) ' LSI_THREAD_TICKS
Stop
If Getthreadinfo(6) - start > 100 Then IsDebugMode = True
' If you debug the application you will not be able to press the CONTINUE-Buton
' within less then 100 milliseconds, otherwise the STOP-statement is not in function
' and you will always be quicker then 100 milliseconds
End Function
Although the comment is in fact wrong (100 tics are not 100ms, you would have to devide by ticks per second to get that value), the code still works and does exactly what you want.
I have a form with a few buttons which execute code when pressed like running validations on the database.
Some code can run for a few minutes so is there any way to show the time remaining or a message to display the % of process completed?
Or pop out a message when code evaluation starts and the message should disappear once code running is completed?
What you are probably looking for is a "Progress Bar".
I've used the Microsoft ProgressBar control (you can find it under Insert->ActiveX Control), and it's not that hard to use. Just set the value of it to a percentage (as an integer, not a decimal).
'foo, being the ProgressBar
me.foo = 70 '70%
There is some good info here on another method: http://www.granite.ab.ca/access/progressbar.htm
In order to do this the "normal" way, you'd need to run your validation in another thread and have it report its progress back to the UI thread. However, I don't believe VBA supports any kind of multithreading.
If your validation routines involve a loop, or even just many separate discrete operations, you can try inserting a DoEvents statement in between loop iterations (or operations), and then have your progress display updated periodically (say, in an Application_OnTime event handler).
I usually have a form I name frmProgress or whatever, with a cancel button and a label for displaying a status message. Then embedded in the form code I have a boolean called bCancel, and when you hit the cancel button it simply sets bCancel as true.
Also in this code I have a routine called ShowPercDone( Idx , NumIdc ) where Idx is the step the code is on, and NumIdc is the number of steps the code will take (assuming each step takes the same amount of time). This works well when I'm running through a for loop, but basically any time I want to display a status update I just call the routine in the form with my message, which I should add runs the doevents command for me.
So that's how the status form works. In the macro I run, I start out by just calling frmProgress.show (0) so that it lets you click the cancel button. Then in my loop when I update the status message I then check frmProgress.bCancel and if it's true I exit out of the macro.
Hope that helps.
Finally to be simple i decided to use the method given here
http://oreilly.com/pub/h/3330#code