macOS cant get Progress Bar to work

[cwebster]

Hi,

I'm just starting out with objective-c and have written a small program that takes input from a text file and does some calculations on the data. I'd like a progress bar to update while the calculations are ongoing.

I have a main app window with a progress bar in it and a controller with a linked IBOutlet.

IBOutlet NSProgressIndicator *myProgressIndicator;

In terms of actions I have a push button that starts the calculation via:

- (IBAction)batch:(id)sender{
	BatchConverterObj =[[BatchConverter alloc]init]; 
	[BatchConverterObj setHdlFactor:[hdlFactorField doubleValue]];
	[BatchConverterObj BatchConvert];
}

The calculation then takes place in another class(BatchConverter) which I've also linked an

IBOutlet for IBOutlet NSProgressIndicator *myProgressBar;

I then have a loop in the BatchConverter class

 for (i = 0, count = [csvData count]; i < count; i = i + 1)
    {
		//start a progress bar
		[myProgressBar setDoubleValue:100*i/(double)count];

But nothing appears to happen.

I've also tried putting the loop in the initial action and again nothing happens and having only one outlet in either class.

Thanks
Craig

 

[Catfish_Man]

You're blocking the main thread while you do your work, so it never gets a chance to draw. Try something like this:

- (void) processNextChunk {
    //do one loop iteration of work
    i++;
    [myProgressBar setDoubleValue:100*i/(double)count];
    [self performSelector:@selector(processNextChunk) afterDelay:0.0];
}

If that introduces too much overhead, you could do it in larger chunks than 1.

 

[kainjow]

Or just make sure your progress bar is using threaded animation before you start the loop:

[myProgressBar setUsesThreadedAnimation:YES];

 

[cwebster]

Thanks

Thanks, got it to work if I do the code in the class that responds to the button press, but not when I transfer over to another class (if that makes any sense)

Cheers
Craig