Swift ?? operator

The nil coalescing operator (a ?? b) unwraps an optional a if it contains a value, or returns a default value b if a is nil.

Matlab: centroids using Kmeans

 [IDX,C] = kmeans(x,3)

c will give the centroids

Merge commit from one branch to another in bitbucket

git cherry-pick commitNumber

Wrapping Google Analytics in Swift

import Foundation

@objc enum MyEventCategory: Int {

    case Category1

    case Category2

}

@objc enum MyEventAction: Int {

   case Action1

   case Action2

   

}

@objc class MyAanalytics  {

    

    func getMyCategory(category: MyEventCategory) -> String {

        return String(stringInterpolationSegment: category)

        

    }

    func getMyAction(action: MyEventAction) -> String {

        return String(stringInterpolationSegment: action)

    }

    func trackEvent(category: MyEventCategory, action: MyEventAction) {

        var label: String, value: NSNumber?

        label = "Any label" // whatever label you want to give

        value = nil

        

        let tracker = GAI.sharedInstance().defaultTracker

        let trackDictionary = GAIDictionaryBuilder.createEventWithCategory(self.getMyCategory(category), action: self. getMyAction(action), label: label, value: value).build()

        tracker.send(trackDictionary as [NSObject : AnyObject])

    }

}

Conditional unwrapping in swift using where clause

checking the optional bool variable as well as that is that variable is true or not


if canPlay = self.dataSource?.functiion() where canPlay= true {

}

Removing conflicts during merging two branches on bitbucket

On terminal

 $git status

remove untracked files if exists

$rm -rf fileWithFullAddress

$git status 

Repeat above till get clean directory

$git checkout FinalDestinationBranchForMerging

$git pull // get update for local branc

Now merge the other branch with it

$git merge MergingBranch

It will show the files having conflicts. Files will get -- head tags 

open Editor, make the changes

After making changes

$ git add ChangedFileWithAddress

$ git status

If need to remove/reset some file from the project 

$ git rest FileToBeRemoved

$ git add -A

$ git status

$ git commit -m 'The message I got while merging the branches'

$ git push

Done

IOS: Delegate and Datasource Swift and objective-c interaction

Delegate will be defined in the class from where the event need to be triggered
For example:
if class name is MyClass in swift

delegate will be defined as

@objc protocol MyClassDelegate: NSObjectProtocol {

    func myClass(myclass: MyClass, myFunction parameter: Parameter)

    

}

if some data is required in the class, the data source is defined as

@objc protocol MyClassDataSource: class {

     func myClass(myClass: MyClass, myFunction parameter: Parameter) -> data?  // like UUImage

}

------- in class implementation

var delegate: MyClassDelegate?

var dataSource : MyClassDataSource?

self.delegate?.myClass(self, myFunction: whateverParameter)

self.dataSource?.myClass(self)

----- using in objective-c

#pragma mark - AudioNoteViewModelControllerDelegate

@interface ObjectivecClass (MyClassDelegate) <AudioNoteViewModelControllerDelegate>

@end

@implementation ObjectivecClass (MyClassDelegate)

-(void) myClass:(MyClass *) myclass myFunction:(Parameter *) parameter  {

}

@end

#pragma mark - AudioNoteViewModelControllerDataSource

@interface ObjectivecClass (MyClassDataSource) <AudioNoteViewModelControllerDataSource>

@end

@implementation ObjectivecClass (MyClassDataSource)

-(Data *) myClass:(MyClass *) myclass myFunction: (Parameter *) parameter {

}

@end

-- in ObjectivecClass  interface

@property (nonatomic, strong) MyClass * myClass;

--- in ObjectivecClass implementation viewDidLoad

     _myClass = [MyClass new];

    _myClass.delegate = self;

    _ _myClass.dataSource = self;

IOS: Google analytics debugging

[[GAI sharedInstance].logger setLogLevel:kGAILogLevelVerbose];

Link

Swift: Remote control buttons for audio Session on lock screen

Make a file to subclass the UIApplication

make the class to respond to events

import UIKit

import Foundation

@objc(MyTest2) class MyTest2: UIApplication

{

    

    

   override func canBecomeFirstResponder() ->Bool{

        return true

    }

   override func remoteControlReceivedWithEvent(event: UIEvent) {

    }

    

}

and use the class in main.m

#import <UIKit/UIKit.h>

#import "AppDelegate.h"

#import "test3-swift.h"

int main(int argc, char * argv[]) {

    @autoreleasepool {

        return UIApplicationMain(argc, argv, NSStringFromClass([MyTest2 class]), NSStringFromClass([AppDelegate class]));

    }

}

and now activate the audioSession and use MPNowPlayingInfoCenter class. Make sure audioSession is not mixing with other.

I have used it in a view controller file

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];

    

    /*

     *  Without some sort of

     *  audio player, the remote

     *  remains unavailable to this

     *  app, and the previous app will

     *  maintain control over it.

     */

    if ([[UIApplication sharedApplication] respondsToSelector:@selector(beginReceivingRemoteControlEvents)]){

        [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

        [self becomeFirstResponder];

    }

    

    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];

    

    if(![[AVAudioSession sharedInstance] setActive:YES error:nil])

    {

        NSLog(@"Failed to set up a session.");

    }

    _player = [[AVPlayer alloc] initWithURL:[NSURL URLWithString:@"http://stream.jewishmusicstream.com:8000"]];

    

    /*  Kicking off playback takes over

     *  the software based remote control

     *  interface in the lock screen and

     *  in Control Center.

     */

    

    [_player play];

    

    

    Class playingInfoCenter = NSClassFromString(@"MPNowPlayingInfoCenter");

    

    if (playingInfoCenter) {

        

        

        NSMutableDictionary *songInfo = [[NSMutableDictionary alloc] init];

        

        

        MPMediaItemArtwork *albumArt = [[MPMediaItemArtwork alloc] initWithImage: [UIImage imageNamed:@"abc.jpg"]];

        

        [songInfo setObject:@"Audio Title" forKey:MPMediaItemPropertyTitle];

        [songInfo setObject:@"Audio Author" forKey:MPMediaItemPropertyArtist];

        [songInfo setObject:@"Audio Album" forKey:MPMediaItemPropertyAlbumTitle];

        [songInfo setObject:albumArt forKey:MPMediaItemPropertyArtwork];

        [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo];

        

        

    }

    

    

}

swift: Using UIApplication Subclass in main.m

Make the swift class like this

import UIKit

import Foundation

@objc(MyTest2) class MyTest2: UIApplication

{

    

    

  

    

}

and modify the main.m

#import <UIKit/UIKit.h>

#import "AppDelegate.h"

#import "test3-swift.h"  //test3 is the project name, not a real file in project

int main(int argc, char * argv[]) {

    @autoreleasepool {

        return UIApplicationMain(argc, argv, NSStringFromClass([MyTest2 class]), NSStringFromClass([AppDelegate class]));

    }

}

Objective-c Getting device width programmatically

CGFloat width = [UIScreen mainScreen].bounds.size.width;

Swift: conditional unwrapping, checking error is nil or not

var error: NSError?

// now use error in functions like

audioSession.overrideOutputAudioPort(AVAudioSessionPortOverride.None, error: &error)

//and now conditional unwrapped

 if let routeChangeError = error {

            NSLog("error %@",routeChangeError)

  }

Swift: changing AVAudioSession route (voice from speaker to headphone and vice versa)

 NSNotificationCenter.defaultCenter().addObserver(self, selector: "handleAVAudioSessionRouteChange:", name: AVAudioSessionRouteChangeNotification, object: nil)

@objc private func handleAVAudioSessionRouteChange(notification : NSNotification) {

        

        println("change route \(notification.userInfo)")

        let audioSession = AVAudioSession.sharedInstance()

        var error : NSError?

        let audioRouteChangeReason = notification.userInfo![AVAudioSessionRouteChangeReasonKey] as UInt

        

        switch audioRouteChangeReason {

        case AVAudioSessionRouteChangeReason.NewDeviceAvailable.rawValue:

            println("headphone plugged in")

        audioSession.overrideOutputAudioPort(AVAudioSessionPortOverride.None, error: &error)

        case AVAudioSessionRouteChangeReason.OldDeviceUnavailable.rawValue:

            println("headphone pulled out")

            audioSession.overrideOutputAudioPort(AVAudioSessionPortOverride.Speaker, error: &error)

        default:

            break

        }

    }

Swift NSUserDefault

setting  

NSUserDefaults.standardUserDefaults().setObject(myvalue, forKey: "mykey")

        NSUserDefaults.standardUserDefaults().synchronize()

reading

Swift

1 2 3 4 5

let defaults = NSUserDefaults.standardUserDefaults() if let name = defaults.stringForKey("myKey") {     println(name) }

stringForKey

IntegerForKey

ObjectForKey 

use based on requirements 

swift - Function with parameter and return value

• func sayHello(personName: String) -> String {
• let greeting = "Hello, " + personName + "!"
• return greeting
• }

objective-c gesture recognizer calling multiple time till state end

In viewdidLoad

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];

    longPress.minimumPressDuration=1.0f;

    [self.deleteDigitButton addGestureRecognizer:longPress];

Long press button

timer is being used to call itself through longPress timer function

- (void)longPress:(UILongPressGestureRecognizer*)gesture {

    

    if( gesture.state == UIGestureRecognizerStateBegan ) {

        NSLog(@"DialerViewController.Long Press");

        

        NSString *digits = [PhoneNumberFormatter unformat: self.TextField.text];

        if(digits.length > 0 && (gesture.state != UIGestureRecognizerStateEnded || gesture.state != UIGestureRecognizerStateCancelled || gesture.state != UIGestureRecognizerStateFailed)) {

            digits = [digits substringToIndex:digits.length - 1];

            self.TextField.text = [PhoneNumberFormatter format:digits];

            [self.TextField setNeedsDisplay];

            

            NSTimeInterval timeInterval = 0.1; //seconds

            [NSTimer scheduledTimerWithTimeInterval:timeInterval

                                             target:self

                                           selector:@selector(longPressTimer:)

                                           userInfo:gesture

                                           repeats:NO];

            

        }

    }

}

longPressTimer function

-(void)longPressTimer:(NSTimer *)timer{

    UILongPressGestureRecognizer *gesture = [timer userInfo];

    [self longPress:gesture];

}