IOS Development Notes

                   var alert: UIAlertView = UIAlertView(title: "Loading", message: "Please wait...", delegate: nil, cancelButtonTitle: "Cancel");

           var loadingIndicator: UIActivityIndicatorView = UIActivityIndicatorView(frame: CGRectMake(50, 10, 37, 37)) as UIActivityIndicatorView            loadingIndicator.center = self.view.center;            loadingIndicator.hidesWhenStopped = true            loadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray            loadingIndicator.startAnimating();

           alert.setValue(loadingIndicator, forKey: "accessoryView")            loadingIndicator.startAnimating()

var currentDevice = UIDevice()

var screenHeight = UIScreen.mainScreen().nativeBounds.height

var screenWidth = UIScreen.mainScreen().nativeBounds.width

if (currentDevice.userInterfaceIdiom == UIUserInterfaceIdiom.Phone) {            println("\(screenHeight)")            println("\(screenWidth)")

import Foundation

let sharedInstance = AppSingleton();

final class AppSingleton{       

var aSharedVariable:NSMutableString!       

private init(){}

Pragma mark is simply a way to organize your methods in the method list pop up button in Xcode

After XCode 4, it only works between methods, so you can add a dummy methods at the beginning of your classes and then use the pragma mark like this: #pragma mark -My methods

Make special characters usable in URLs

- (NSString *)escape:(NSString *)text {     return [(NSString *)CFURLCreateStringByAddingPercentEscapes(         NULL,         (CFStringRef)text,         NULL,         (CFStringRef)@”!*’();:@&=+$,/?%#[]”,         CFStringConvertNSStringEncodingToEncoding(NSUTF8StringEncoding))         autorelease]; }

The search text is URL-encoded using the escape: method to ensure that we’re making a valid URL. Spaces and other special characters are turned into things such as %20.

Nonatomic

nonatomic is used for multi threading purposes. If we have set the nonatomic attribute at the time of declaration, then any other thread wanting access to that object can access it and give results in respect to multi-threading.

Copy

copy is required when the object is mutable. Use this if you need the value of the object as it is at this moment, and you don't want that value to reflect any changes made by other owners of the object. You will need to release the object when you are finished with it because you are retaining the copy.

Retain

retain is required when the attribute is a pointer to an object. The setter generated by @synthesize will retain (aka add a retain count to) the object. You will need to release the object when you are finished with it. By using retain it will increase the retain count and occupy memory in autorelease pool.

Strong

strong is a replacement for the retain attribute, as part of Objective-C Automated Reference Counting (ARC). In non-ARC code it's just a synonym for retain.

This is a good website to learn about strong and weak for iOS 5. http://www.raywenderlich.com/5677/beginning-arc-in-ios-5-part-1

Weak

weak is similar to strong except that it won't increase the reference count by 1. It does not become an owner of that object but just holds a reference to it. If the object's reference count drops to 0, even though you may still be pointing to it here, it will be deallocated from memory.

The above link contain both Good information regarding Weak and Strong.

The difference is that an object will be deallocated as soon as there are no strong pointers to it. Even if weak pointers point to it, once the last strong pointer is gone, the object will be deallocated, and all remaining weak pointers will be zeroed out.

Perhaps an example is in order.

Imagine our object is a dog, and that the dog wants to run away (be deallocated).

Strong pointers are like a leash on the dog. As long as you have the leash attached to the dog, the dog will not run away. If five people attach their leash to one dog, (five strong pointers to one object), then the dog will not run away until all five leashes are detached.

Weak pointers, on the other hand, are like little kids pointing at the dog and saying "Look! A dog!" As long as the dog is still on the leash, the little kids can still see the dog, and they'll still point to it. As soon as all the leashes are detached, though, the dog runs away no matter how many little kids are pointing to it.

As soon as the last strong pointer (leash) no longer points to an object, the object will be deallocated, and all weak pointers will be zeroed out.

Found this solution on Stackoverflow.

Here is how I solved it. I am using IB in which I added a UIButton to the view.

I defined the button selected by default and selected my image for the selected state (Use drope-down list in inspector window to choose "Selected State Configuration" before selecting the image).

Create an IBAction in the controller and connect the button to that action.

Then see the code below:

-(IBAction) toggleUIButtonImage:(id)sender{  if ([sender isSelected]) {      [sender setImage:unselectedImage forState:UIControlStateNormal];      [sender setSelected:NO];  }else {      [sender setImage:selectedImage forState:UIControlStateSelected];      [sender setSelected:YES];   }  }

-(IBAction) rotateButton:(id)sender{     UIButton *btn = (UIButton *)sender;     [UIView beginAnimations:nil context:nil];     [UIView setAnimationDuration:0.1];         btn.transform = CGAffineTransformMakeRotation((CGFloat)((20 * M_PI ) / 180));     btn.transform = CGAffineTransformMakeRotation(0);         [UIView commitAnimations]; }

Open up the Terminal

cd into your iPhone project directory

cd into YourApp.xcodeproj

Edit the file project.pbxproj by using a text editor (open -a TextEdit filename)

Search for the string PROVISIONING_PROFILE

Surround the line containing PROVISIONING_PROFILE, with /* */ (comment block).

Do this for all lines containing PROVISIONING_PROFILE