i'm a noob in Objective C. I'm having the following confusion.
How do i convert a float value obtained from progressView.progress in a string?
I tried this
NSString *progressStatus = [NSString stringWithFormat:#"%f", progressView.progress];
label.text = progressStatus;
But this say EX_BAD_ACCESS
some help please.
Thank You.
The snippet you posted reads correctly. The most likely source of your error is that the UIProgressView has yet to be initialized when this code is called. It is also possible that the UILabel is not correctly set up.
If you created these UI elements in the IB, check the connections. If you created them programmatically, then check that they are allocated and initialized correctly.
Also ensure that you are setting the text of the label after the progressView is created.
Related
I've created a .xib file with a uiview solely for the pdf document that I have created. I've primarily followed this tutorial for code:
http://www.raywenderlich.com/6818/how-to-create-a-pdf-with-quartz-2d-in-ios-5-tutorial-part-2
From the above, I can't edit labels (plain or attributed) from the interface builder as even after changing size, it doesn't apply when the app is run. (I suspect the issue may lie within the methods drawText or drawLabels).
I then tried to create an attributed string, however the methods don't take it. I tried to convert the drawtext by copying and taking the argument of an nsmutableattributedstring however this caused problems with the CFStringRef.
I appreciate your time for any help.
Solved it by making a separate method as below (I used + since I have this inside an NSObject and is a class method rather than in a UIViewController):
+(void)addText:(NSString*)text withFrame:(CGRect)frame withFont:(UIFont*)font;
{
[text drawInRect:frame withFont:font];
}
Outside the method, declaring inputs and calling it:
UIFont *font = [UIFont fontWithName:#Helvetica-Bold" size:7];
[self addText: yourStringHere
withFrame:CGRectMake(yourXPosition, yourYPOsition, yourFrameWidth, yourFrameHeight)
withFont:font];
I wonder if it's much simplified like so because the tutorial I used is now outdated?
If anything I hope this helps others :)
I am writing an iOS application for (among many features) calculating alcohol content from sugar before and after fermentation for homebrewers. Now the problem is; every time I run my app in the simulator, it crashes with "Thread 1: Signal SIGBART" once I enter the UIViewController with the text fields, labels and buttons used in this function (in the implementation):
- (IBAction)calcAlc:(id)sender {
double ogVal = [[oGtext text]floatValue];
double fgVal = [[fGtext text]floatValue];
double alcoContent = ((1.05*(ogVal-fgVal))/fgVal)/0.79;
NSString *theResult = [NSString stringWithFormat:#"%1.2f",alcoContent];
alcContent.text = theResult;
}
I'm really stuck here -- any help is very appreciated. Thanks in advance!
You should check if fgVal is ever 0, since you are dividing by fgVal.
You will also want to use doubleValue instead of floatValue, since you are declaring them as double.
I think you should try float in place of double.
Now put break points on each and every method and debug it to get the exact point where you application is getting crashed and then you will be able to find the solution.
Also be sure to connect each and every ib outlet and action in your storyboard or nib(whatever you are using).
Please notify if it works..:)
I have a problem.
I have an NSObjectController called "mapController" and I want to put some defaults when the object is created. I do this inside the windowControllerDidLoadNib method of my document, as suggested by the docs. But…
if (![mapController content]){ // No map defined yet.
[mapController add: self]; // This should create the instance.
NSLog(#"%#",[mapController content]); // Gives NULL.
I tried:
BOOL ok = [mapController fetchWithRequest:nil merge:NO error:nil];
NSLog(#"%#",[mapController content]); // Gives NULL.
The content of mapController is in the Core Data "scratch pad" but I can't access it. I have to set one of its attributes like this:
[[mapController content] setValue:[matrix colorReference] forKey:#"mapData"];
This gives no error, the file is marked as changed, but it I test the value:
NSLog(#"%#",[mapController content]); // Gives NULL.
When the heck it the controller's content really HERE? Something appears on the screen but… what actually? Reading the docs doesn't help me…
OK, I found the answer in the docs:
add: Creates a new object and sets it as the receiver’s content object.
Discussion
Creates a new object of the appropriate entity (specified by
entityName) or class (specified by objectClass)—see newObject—and sets
it as the receiver’s content object using addObject:.
Special Considerations
Beginning with Mac OS X v10.4 the result of this method is deferred
until the next iteration of the runloop so that the error presentation
mechanism can provide feedback as a sheet.
That's why
[[mapController content] setValue:[matrix colorReference] forKey:#"mapData"];
worked fine when called elsewhere in the app. It was a few iterations later…
Well… maybe this post will save you a couple of hours you could use to sleep longer.
Regards,
Bernard
I don't think its your mapController, I think it is your NSLog. Try this:
NSLog(#"%#", mapController);
also try getting simple data from the content, like the float value of the CGColorRef so you can use other formatters like %f.
I would have tested this but I cannot seem to create an instance of NSObjectController because it is an undeclared identifier. What framework is it defined in? Did you have to #import anything?
I am having a major problem with my iPhone app. My problem seems basic but I cannot find out the reason for the error. I have a NSString saveDescription that is set by user's input.
savede = civilsJobDescTb.text;
I then call in a NSLog to check the string has been set, and it is. So I have no problem there.
Later in the program I create a PDF file with several details. Everything works ok except the NSString that I have set earlier. It seem as if the string no longer exists. I get an error from it. EXC_BAD_ACCESS or something like that.
Now for the weird thing. This only happens when I have a whitespace in the text box. Eg: I enter "ok" and it will work without problem. But if I enter "Everything is ok" then I get errors.
I can't see where the problem is. Any ideas?
You didn't specify if your "savede" is an ivar (instance variable) but assuming that it is,
and if you are using ARC, set a strong property to it:
#property (nonatomic, strong) NSString * savede;
self.savede = civilsJobDescTb.text;
If you are not using ARC, then make sure to retain your "savede" string after setting it. Something like:
savede = civilsJobDescTb.text;
[savede retain];
(making sure to release it when you are truly finished with it).
You can also make a copy of the string (in case the label that it's coming from disappears, or is cleared, or somehow disappears).
[savede setString: civilsJobDescTb.text];
[savde retain];
I like to create an instance of a custom class by passing it a value that upon init will help set it up. I've overridden init and actually changed it to:
- (id)initWithValue:(NSInteger *)initialValue;
i'd like to store this value in a property of the instantiated object and use the value to generate the filename of a UIImage that will be associated with it.
My question is how best to go about this in Cocoa/Obj-C. is an NSInteger the best parameter for my needs or would an NSString be better? Or is there another design pattern? I'm not familiar with all the creative methods available to help in this situation. Assume my class properties are:
#interface MyView : UIView {
UIImage *image;
NSInteger value;
If I stick with the NSInteger as a parameter I can easily assign value to it. but then would need to generate "image12.png" from that value (assume NSInteger = 12) to set up my UIImage. Something like "image"+initialValue+".png". Which I believe is verbosely expressed in Obj-C as:
NSString *myValue = #"image";
[myValue stringByAppendingString:[initialValue stringValue]]; //NSInteger may not respond to stringValue?!?
[myValue stringByAppendingString:#".png"]
This is where my understanding of Obj-C breaks down. Feels to me like this should be easier but I'm still confused.
Now if initialValue was an NSString with the value of #"12" maybe it is? then self.value = [initialValue integerValue];
and I could build image with multiple stringByAppendingString calls. Just seems tedious for something so simple in other languages.
What's best way to handle something like this?
Your init method looks fine, and if you're only dealing with integer values, you do want to use NSInteger as opposed to NSString or even NSNumber. The one thing you might want to change is the parameter you're passing should be (NSInteger), not (NSInteger *) - an NSInteger is not an object, but in Objective-C is a primitive type similar to int.
You can build the image name by using NSString's stringWithFormat: selector, as such:
NSInteger myInteger = 12;
NSString *imageString = [NSString stringWithFormat:#"image%d.png", myInteger];
Just to expand on what Tim mentioned, an NSInteger is actually just a #define. On 32-bit architectures, it's equivalent to an int and on 64-bit architectures it's a long.
If you need to treat an integer as an object (to put it in an NSDictionary, for instance), you can wrap it in an instance of NSNumber using numberWithInteger:.
Hope that helps!
One other thing to keep in mind though is that when you're dealing with paths NSString gives you stringByAppendingPathExtension: and stringByAppendingPathComponent:, both of which handle things like trailing slashes better than if you just use stringByAppendingString:.
If you describe a little more about what this object does and what kind of images it's loading I might be able to offer some advice if I can think of a better way of creating the filenames, instead of just passing a number around.