iOS Code Chunks – Part 2

In Xcode, click Run > Console to see NSLog statements.

NSLog(@"log: %@ ", myString);
 NSLog(@"log: %f ", myFloat);
 NSLog(@"log: %i ", myInt);

CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 109.0f);
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"myImage.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];

CGRect webFrame = CGRectMake(0.0, 0.0, 320.0, 460.0);
 UIWebView *webView = [[UIWebView alloc] initWithFrame:webFrame];
 [webView setBackgroundColor:[UIColor whiteColor]];
 NSString *urlAddress = @"http://www.google.com";
 NSURL *url = [NSURL URLWithString:urlAddress];
 NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
 [webView loadRequest:requestObj];
 [self addSubview:webView];
 [webView release];

UIApplication* app = [UIApplication sharedApplication];
 app.networkActivityIndicatorVisible = YES; // to stop it, set this to NO

NSArray *myImages = [NSArray arrayWithObjects: [UIImage imageNamed:@"myImage1.png"],
[UIImage imageNamed:@"myImage2.png"],
[UIImage imageNamed:@"myImage3.png"],
[UIImage imageNamed:@"myImage4.gif"],  nil];
UIImageView *myAnimatedView = [UIImageView alloc];
[myAnimatedView initWithFrame:[self bounds]];
myAnimatedView.animationImages = myImages;
myAnimatedView.animationDuration = 0.25; // seconds
myAnimatedView.animationRepeatCount = 0; // 0 = loops forever
[myAnimatedView startAnimating];
[self addSubview:myAnimatedView];
[myAnimatedView release];

Show something moving across the screen. Note: this type of animation is “fire and forget” — you cannot obtain any information about the objects during animation (such as current position). If you need this information, you will want to animate manually using a Timer and adjusting the x&y coordinates as necessary.

CABasicAnimation *theAnimation;
theAnimation=[CABasicAnimation animationWithKeyPath:@"transform.translation.x"];
theAnimation.duration=1;
theAnimation.repeatCount=2;
theAnimation.autoreverses=YES;
theAnimation.fromValue=[NSNumber numberWithFloat:0];
theAnimation.toValue=[NSNumber numberWithFloat:-60];
[view.layer addAnimation:theAnimation forKey:@"animateLayer"];

NSString and int

The following example displays an integer’s value as a text label:

currentScoreLabel.text = [NSString stringWithFormat:@"%d", currentScore];

Draggable items

Here’s how to create a simple draggable image.
1. Create a new class that inherits from UIImageView

@interface myDraggableImage : UIImageView
{
}

2. In the implementation for this new class, add the 2 methods:

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
  // Retrieve the touch point
  CGPoint pt = [[touches anyObject] locationInView:self];
  startLocation = pt;
  [[self superview] bringSubviewToFront:self];
} 
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
   // Move relative to the original touch point
 CGPoint pt = [[touches anyObject] locationInView:self];
 CGRect frame = [self frame];
 frame.origin.x += pt.x - startLocation.x;
 frame.origin.y += pt.y - startLocation.y;
 [self setFrame:frame];
}

3. Now instantiate the new class as you would any other new image and add it to your view

dragger = [[myDraggableImage alloc] initWithFrame:myDragRect];
[dragger setImage:[UIImage imageNamed:@"myImage.png"]];
[dragger setUserInteractionEnabled:YES];

Here is how to make the phone vibrate (Note: Vibration does not work in the Simulator, it only works on the device.)

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

Sound will work in the Simulator, however some sound (such as looped) has been reported as not working in Simulator or even altogether depending on the audio format. Note there are specific filetypes that must be used (.wav in this example).

SystemSoundID pmph;
id sndpath = [[NSBundle mainBundle]
pathForResource:@"mySound" ofType:@"wav" inDirectory:@"/"];
CFURLRef baseURL = (CFURLRef) [[NSURL alloc] initFileURLWithPath:sndpath];
AudioServicesCreateSystemSoundID (baseURL, &pmph);
AudioServicesPlaySystemSound(pmph);
[baseURL release];

Threading

1. Create the new thread:

[NSThread detachNewThreadSelector:@selector(<strong>myMethod</strong>)   toTarget:self withObject:nil];

2. Create the method that is called by the new thread:

- (void)<strong>myMethod</strong> {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
*** code that should be run in the new thread goes here ***
[pool release];
}

What if you need to do something to the main thread from inside your new thread (for example, show a loading symbol)?
UseperformSelectorOnMainThread.

[self performSelectorOnMainThread:@selector(<strong>myMethod</strong>) withObject:nil waitUntilDone:false];

Reading crash logs