Archive for the ‘Development’ Category

Xcode cannot run using the selected device. No provisioned iOS device … iPhone 3G

There is no iOS 4.3 update for the iPhone 3G and iPod Touch 2G available.  If you have set the Deployment Target to 4.3 in your Xcode project settings you will get an error.

To run the app on your iPhone 3G you have to set the Deployment Target to 4.2.

Free Icons for iOS, Android & Windows Phone 7

Delete SQLite Database of iPhone/iPad Simulator App

You can find and delete the sqlite database file of your app here:

/Macintosh HD/Users/<username>/Library/Application Support/iPhone Simulator/<Simulator-Version>/Applications/<app-key>/Documents/

Check if view is visible

if (self.navigationController.visibleViewController == self) {}
Categories: CodeSnippets, Development, iOS

Exceptions and error handling in Objective-C

Compiler directives that are used for exception handling:

1. @try: block of code that can throw an exception.

2. @catch: define block of code to handle exception thrown by try block, this is usually an NSException object.

3. @finally: defines a block of code that executed whether an exception is thrown or not.

4. @throw: once your program detects an exception, it must propagate the exception to code that handles it. This code is called the exception handler. This entire process of propagating an exception is referred to as “throwing an exception”.

@try {
   [object objectForKey:@"yeah"];
@catch (NSException * e) {
   NSLog(@"catching %@ reason %@", [e name], [e reason]);
@finally {

For more informations have a look at the documentation here.

Categories: Development, iOS, Objective-C

NSString Basics

Creating strings

NSString *myFirstString = @"foo";
NSString *mySecondString = [[NSString alloc] initWithFormat:
   @"%@%@%@i", myFirstString, @"bar", 1];

Comparing strings

NSString *myString = @"foo";
if([myString isEqualToString:@"foo"]) {
   NSLog (@"Strings are equal!");

Finding strings within strings

NSString *myString = @"foo";
NSString *searchForMe = @"Howdi";
NSRange range = [myString rangeOfString : searchForMe];
int location = range.location;
int length = range.length;

if (location != NSNotFound) {

   NSString *locationAndLength = [[NSString alloc] initWithFormat:
      @"Location: %i, length: %i", location, length];
   NSLog(@"I found something.");

Replacing strings within strings

NSString *myString = @"foo";
myString = [myString stringByReplacingOccurancesOfString:@"oo"

Extracting substrings from strings

There are 3 methods that allow to extract substrings from a parent string:

  • -substringToIndex:
  • -substringWithRange:
  • -substringFromIndex: (which respectively take a substring from the beginning, middle, and end of a parent string)

The first method substringToIndex returns a new string which is composed of the characters from the beginning of the receiver string up to (but not including) the character at the specified index:

NSString *aString = @"Running out of ideas for strings.";
NSString *substring = [aString substringToIndex:7];
// result: @"Running"

The method substringFromIndex works in the same way, except now the substring starts at the specified index of the receiver (including the character at the index) and includes all the characters to the end of the receiver:

NSString *substring = [aString substringFromIndex:25];
// result: @"strings"

Finally, we have the method which lets us arbitrarily extract a substring from anywhere within the parent string substringWithRange. The argument to this method is an NSRange:

NSString *substring = [aString substringWithRange:NSMakeRange(15, 5)];
// result: @"ideas"

Here the range starts with the 15th character, “i”, and extends to include the next four characters, giving us a length of 5, “ideas”.

How to find class type of an object

February 1, 2011 1 comment
NSLog(@"Is of type: %@", [myObject class]);
NSLog(@"Is of type NSString?: %@", ([[myObject class] isMemberOfClass:
                                    [NSString class]])? @"Yes" : @"No");
NSLog(@"Is a kind of NSString: %@", ([[myObject classForCoder]
                  isSubclassOfClass:[NSString class]])? @"Yes" : @"No");

Objective-C Structs

struct ExampleStruct {
   NSString* something;
   NSInteger somethingElse;
// useage:
// struct ExampleStruct Struct;
// Struct.something = @"foo";
// Struct.somethingElse = 2;
// or
//struct ExampleStruct Struct = { @"foo", 2, ... };
Categories: iOS, Objective-C

Iconless iPhone simulator

Does anyone know how this might occur and how to fix it?

iconless iPhone simulator

Categories: iOS, iOS Simulator, Xcode

Location via GPS with iOS

First add the Core Location framework:

  • right click on the “Frameworks” group and go to Add > Existing Frameworks…
  • select the CoreLocation.framework

Then you can use the framework in your app:

#import <CoreLocation/CoreLocation.h>

@interface MyLocation : NSObject <CLLocationManagerDelegate> {
	CLLocationManager *locationManager;

#import "MyLocation.h"

@implementation MyLocation

- (id) init {
   if ((self = [super init])) {
      // Custom initialization
      locationManager = [[CLLocationManager alloc] init];
      locationManager.delegate = self;
      locationManager.distanceFilter = kCLDistanceFilterNone;
      locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
     [locationManager startUpdatingLocation];
   return self;

- (void) locationManager:(CLLocationManager *)manager
   didUpdateToLocation:(CLLocation *)newLocation
   fromLocation:(CLLocation *)oldLocation {

   int degrees = newLocation.coordinate.latitude;
   double decimal = fabs(newLocation.coordinate.latitude - degrees);
   int minutes = decimal * 60;
   double seconds = decimal * 3600 - minutes * 60;
   NSString *lat = [NSString stringWithFormat:@"%d° %d' %1.4f\"", 
                         degrees, minutes, seconds];

   degrees = newLocation.coordinate.longitude;
   decimal = fabs(newLocation.coordinate.longitude - degrees);
   minutes = decimal * 60;
   seconds = decimal * 3600 - minutes * 60;
   NSString *lon = [NSString stringWithFormat:@"%d° %d' %1.4f\"", 
                         degrees, minutes, seconds];
Categories: CodeSnippets, iOS, Objective-C