IOS Coding Tips for Beginners

1. Create view objects in Interface builder not in source code.

2. Flower brackets always be there in if conditions or while loops, even it has single statement.

3. Give one line space between @implementation and @synthesize

4. Open flower bracket “{” should start in next line.

5. Give one line space above conditional or loop statements like if, while, for.

6. The method name itself should resembles its behavior.

7. Remove unnecessary methods which are created by the file templates.

8. Use Edit->Format->Re-Indent to re-indent the selection of statements.

9. Don’t use string literals as keys, make the string literal as constant and use that. Place all constants in a common file.

10. Try to use property directly than calling the accessory method. for example Object.memberVariable than [Object memberVariable];

11. Try to define all literals in common file.

12. Instead of using literals, create meaningful constants for them in common file and use them.

13. Always group the things like constants, statements, etc.

14. The format for method signature should be like
– (void) methodName:(id) sender;

15. One line space between logical group of statements and two lines between physical groups.

16. Try to eliminate autorelease objects, instead use retain and release.

17. If you are declaring a UI object, please suffix the type to the variable. For example, if you are declaring a UILabel object with name ‘userName’, then name it ‘userNameLabel’.

18. Maintain all image names in lowercase with underscore dividing the inline words.

19. Directly access the variable instead of using property in the same class. For example, don’t access

UITableView mTableView;
@Property () UITableView *tableView;
//To reload the table in the same class use
[mTableView reloadData]; // correct
[self.tableView reloadData]; //wrong

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CoreTelephony CTCallCenter

The [[CTCallCenter alloc] init] must be run in the main queue. Is it thread safe ??? Better call it on main thread only.

There is an iOS bug that causes instances of the CTCallCenter class to sometimes get notifications after they have been deallocated. Instead of instantiating, using, and releasing instances you must instead retain and never release them to work around the bug.

static CTCallCenter *netInfo; static dispatch_once_t dispatchToken; if (!netInfo) { dispatch_once(&dispatchToken, ^{ netInfo = [[CTCallCenter alloc] init]; }); }

 

How to programmatically know Bluetooth headset is connected to iOS device

Call this method to find out the bluetooth headset is connected or not.

 

- (BOOL) isBluetoothHeadsetConnected
{
    AVAudioSession *session = [AVAudioSession sharedInstance];
    AVAudioSessionRouteDescription *routeDescription = [session currentRoute];

    DEBUGLOG(@"Current Routes : %@", routeDescription);

    if (routeDescription)
    {
        NSArray *outputs = [routeDescription outputs];

        if (outputs && [outputs count] > 0)
        {
            AVAudioSessionPortDescription *portDescription = [outputs objectAtIndex:0];
            NSString *portType = [portDescription portType];

            DEBUGLOG(@"dataSourceName : %@", portType);

            if (portType && [portType isEqualToString:@"BluetoothA2DPOutput"])
            {
                return YES;
            }
        }
    }

    return NO;
}

How to enable or disable Proximity sensor programmatically in iPhone

Use the following API to enable/disable the proximity sensor.

[UIDevice currentDevice].proximityMonitoringEnabled = NO; // Disables the Proximity Sensor

[UIDevice currentDevice].proximityMonitoringEnabled = YES; // Enables the Proximity Sensor

Not all iOS devices have proximity sensors. To determine if proximity monitoring is available, attempt to enable it. If the value of the proximityMonitoringEnabled property remains NO, proximity monitoring is not available.

Convert iPad xib to iPhone version

We can go with the following approach to get iPhone version of iPad xibs already exist in the project. With this approach we no need to create a new xib and manually add all the subviews.

1. Xcode recognises the iPhone version of a XIB if the suffix is ~iphone (lowercase only) and iPad version if its ~ipad. If no suffix exists then it will consider it as an iPhone version. Lets suffix all the existing xib names with ~ipad.

2. Duplicate all the xib files and open them in TextEditor and do the following.

change “com.apple.InterfaceBuilder3.CocoaTouch.iPad.XIB” to “com.apple.InterfaceBuilder3.CocoaTouch.XIB”
change “iOS.CocoaTouch.iPad” to “iOS.CocoaTouch”
change iPad size (width=”1024″ height=“768”) to iPhone size (width=“320″ height=“568″)

3. Add the xib to the project and open it on Xcode.

4. Select the root view and go to the attributes inspector.

5. Change the orientation to portrait and size to Retina 4-inch Full Screen.

6. Adjust the frame of all the subviews.

Objective-C – How to use member variables in the categories.

.h

@interface UIView (ObjectTagAdditions)
@property (nonatomic, retain) id objectTag;
@end

.m

#import <objc/runtime.h>
static char const * const ObjectTagKey = "ObjectTag";

@implementation UIView (ObjectTagAdditions)
@dynamic objectTag;

- (id)objectTag {
    return objc_getAssociatedObject(self, &ObjectTagKey);
}

- (void)setObjectTag:(id)newObjectTag {
    objc_setAssociatedObject(self, &ObjectTagKey, newObjectTag, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

Cited from : http://oleb.net/blog/2011/05/faking-ivars-in-objc-categories-with-associative-references/

Convert yyyy-MM-ddTHH:mm:ss.SSSZ format to default timezone

– (NSDate *) localDateStringForISODateTimeString:(NSString *) anISOString

{
NSDateFormatter *isoDateFormatter = [[NSDateFormatter alloc] init];
[isoDateFormatter setDateFormat:@”yyyy-MM-dd’T’HH:mm:ss.SSS’Z'”];
[isoDateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@”UTC”]];

NSDateFormatter *userFormatter = [[NSDateFormatter alloc] init];
[userFormatter setDateFormat:@”yyyy-MM-dd HH:mm:ss”];

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@”yyyy-MM-dd HH:mm:ss”];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@”UTC”]];

NSDate *date = [isoDateFormatter dateFromString:anISOString];
return [dateFormatter dateFromString:[userFormatter stringFromDate:date]];
}