iPhone Development (Object C) Tip

1. How to create (access) AppDelegate object

             projectNameAppDelegate* sharedApplication = (projectNameAppDelegate *) 
                                                                                                     [[UIApplication sharedApplication] delegate];

             Using this Object you can access main Window also.
  

     2.   Scheduling to method  

            [NSTimer scheduledTimerWithTimeInterval:1.0f target:self

                                   selector:@selector(didFinishMainURL) userInfo:nil repeats:NO]; 

 
 

      3. Re-create frame parameter from existing frame

           

            UIImageView *imageView = [productRowData objectForKey:@"product_image"];

            CGRect rect = imageView.frame;

            rect.size.height = 80;

            rect.size.width = 75;

            imageView.frame = rect;

            imageView.tag = 0;    // tag our images for later use when we place them in serial fashion

            CGRect frame = imageView.frame;

            //frame.origin = CGPointMake(15, 3);

            frame.origin = CGPointMake(0, 0);

            imageView.frame = frame;

Get Location Data (GPS) in iPhone

Using this post you can learn about 

• How to create shared object in Obective C
• How to create custom 'init' method
• How to get GPS location using iPhone 

//Reciving data for main screen

    POLocationService* locationService = [POLocationService sharedLocationService];

    locationService.delegate = self;

    [locationService requestLocationInformationFor:@"for finding deals near to you!"];*/

 POLocationService.h   file

#import "Foundation/Foundation.h"

#import "CoreLocation/CoreLocation.h"

@interface POLocationService : NSObject "CLLocationManagerDelegate"{

    CLLocationManager *locationManager_;

    id delegate_;

    NSString* locationString_;

}

@property (nonatomic, retain) CLLocationManager *locationManager;

@property (nonatomic, assign) id delegate;

@property (nonatomic, retain) id locationString;

+ (POLocationService *)sharedLocationService;

- (void)requestLocationInformationFor:(NSString *)purpose;

 

@end

 POLocationService.m   file

#import "POLocationService.h"

static POLocationService *sharedLocationService = nil;

@implementation POLocationService

@synthesize locationManager = locationManager_;

@synthesize delegate = delegate_;

@synthesize locationString = locationString_;

+ (POLocationService *)sharedLocationService

{

    @synchronized(self) {

        if (sharedLocationService == nil) {

            sharedLocationService = [[self alloc] init];

        }

    }

    return sharedLocationService;

}

- (id)init

{

    if (self = [super init]) {

        self.locationManager = [[CLLocationManager alloc] init];

    }

   

    return self;

}

- (void)requestLocationInformationFor:(NSString *)purpose

{

    //didRequest_ = YES;

    locationManager_.delegate = self;

    locationManager_.purpose = purpose;

    locationManager_.desiredAccuracy = kCLLocationAccuracyHundredMeters;

    locationManager_.distanceFilter = 200;

    [locationManager_ startUpdatingLocation];

}

/*

 * We want to get and store a location measurement that meets the desired accuracy. For this example, we are

 *      going to use horizontal accuracy as the deciding factor. In other cases, you may wish to use vertical

 *      accuracy, or both together.

 */

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

    NSString *location = [NSString stringWithFormat:@"%lf;%lf",newLocation.coordinate.latitude,newLocation.coordinate.longitude];

    self.locationString = location;

   

    [delegate_ performSelector:@selector(didFindLocation:userDenied:) withObject:location withObject:[NSNumber numberWithInt:0]]; // Third arg is whether user denied

}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {

    // The location "unknown" error simply means the manager is currently unable to get the location.

    if ([error code] != kCLErrorLocationUnknown) {

        [locationManager_ stopUpdatingLocation];

        locationManager_.delegate = nil;

        [delegate_ performSelector:@selector(didFindLocation:userDenied:) withObject:nil withObject:[NSNumber numberWithInt:0]];

    } else if ([error code] != kCLErrorDenied || [error code] != kCLErrorRegionMonitoringDenied) {

        [delegate_ performSelector:@selector(didFindLocation:userDenied:) withObject:nil withObject:[NSNumber numberWithInt:0]];

    } else {

        [delegate_ performSelector:@selector(didFindLocation:userDenied:) withObject:nil withObject:[NSNumber numberWithInt:0]];

    }

}

- (void)dealloc

{

    [locationManager_ stopUpdatingLocation];

    locationManager_.delegate = nil;

    [locationManager_ release];

    [super dealloc];

}

@end

How to create shared object in Obective C

static AASharedObjectClassName *sharedObjectName = nil;

@implementation AASharedObjectClassName

+ (AASharedObjectClassName *)sharedObjectService

{

    @synchronized(self) {

        if (sharedObjectName == nil) {

            sharedObjectName = [[self alloc] init];

        }

    }

    return sharedObjectName;

}

How to create custom 'init' method in Objective C

- (id)init

{

    if (self = [super init]) {

       

         //you can implement custom class here

    }

   

    return self;

}

Radio buttons for iPhone application

Add buttons on view of controller

        for (int i = 0; i < 3; i++) {

            UIButton *but = [UIButton buttonWithType:UIButtonTypeCustom];

            [but setImage:[UIImage imageNamed:@"checkbox.png"] forState:UIControlStateNormal];

            [but setImage:[UIImage imageNamed:@"checkedbox.png"] forState:UIControlStateSelected];

            [but setFrame:CGRectMake(0, 0, 25, 25)];

            [but setCenter:CGPointMake(410, 385+i*40)];

            if (i == 0) {

                [but setSelected:YES];

            }

            [but setTag:i];

            [but addTarget:self action:@selector(checkboxButton:) 

                                                          forControlEvents:UIControlEventTouchUpInside];

            [self addSubview:but];

        }

Action for buttons:

- (void)checkboxButton:(UIButton *)button

{

    for (UIButton *but in [self subviews]) { // This is the view that button are in

        if ([but isKindOfClass:[UIButton class]] && ![but isEqual:button]) {

            [but setSelected:NO];

        }

    }

    if (!button.selected) {

        button.selected = !button.selected;

    }

}