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A Closer Look at the MKMapViewDelegate Protocol

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The MKMapViewDelegate is a protocol that defines how your app can receive updates when changes occur to either the map or any annotations on the map.

As of iOS 6 there are 18 methods available in 7 categories that you can optionally use to receive the updates. Today, I want to cover what each of these methods can do and how you can use them to help bring more functionality to your app.

MKMapView operations often run asynchronously which is why the MKMapViewDelegate comes in handy as actions are processed while you continue using the map and then your app is notified of various changes as available and needed.

This post is not a tutorial as such. Instead, I am just listing the various methods along with details of how they work and what they do. If you want to see some examples of how they are implemented, take a look at the categories listed to the right and select the Map Kit Framework to see tutorials about the various methods.

Responding to Map Position Changes

There are two methods within this category. These are mapVew:regionWillChangeAnimated: and mapView:regionDidChangeAnimated:

[Read more…]

The MKUserLocation Class and How to Customise It

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location-dotThe MKUserLocation is a class that is used to create an annotation for the users current location. This particular class is responsible for the blue dot you see on the screenshot to the left. Although I call it a blue dot, it is actually a type of annotation specifically used for the current location of the device.

The MKUserLocation class has 5 properties and no methods. The location, updating and heading property are readonly as you cannot set your location programatically, likewise you cannot update your heading programatically. The way you would set these properties is simply by pointing the phone in another direction or by walking somewhere else. The new values would then be provided to you.

The title and subtitle properties are not readonly. What this means is that you can change the text that is provided when you tap on the blue dot. By default it says “Current Location”. If you set the title and subtitle to some custom text, you can display something different if you wish.

You would do that with the following code:

self.mapView.userLocation.title = @"I'm Here";
self.mapView.userLocation.subtitle = @"Come and Find Me";

title-subtitleThe result would be what you see to the right.

The MKUserLocation class is relatively simple. It provides you with where you are, where you are heading and lets you know if the location is being updated. Additionally, we have seen that it also allows you to set the title and subtitle of the annotation as pictured to the right.

This ends this brief tutorial. Next time, we’ll look at how you can customise the look of the MKUserLocation annotation just in case you don’t want to use the standard blue dot.

MKPointAnnotation Tutorial

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MKPointAnnotationThe MKPointAnnotation is the basic version of an annotation that can be used to display a pin along with a title and subtitle. These can come in handy for displaying basic information on a map. If you want to do more than show a point on a map with a title, then you will need to use MKAnnotation and MKAnnotationView. We’ll look at both of those later in this tutorial. Note that you can change the pin as well and provide a custom image. I’ll show you how in the tutorial below.

The screenshot to the left shows what an MKPointAnnotation looks like in its basic form. This is what this short tutorial will cover today. To get started, download the tutorial from yesterday or create a new Single View Application and drag a map to the view, connect it up as an IBOutlet, import MapKit.framework and the CoreLocation.framework. Include both of these in your header file of the associated class with the view. [Read more…]

MKMapView and MKMapView Delegate Tutorial

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The Map Kit Framework is what you use to add a map to your application. There are a number of classes found within the framework that let you provide a rich experience for your users. Today we will look at two of the basic ones. These are MKMapView and MKMapViewDelegate. We will add more tutorials over the coming weeks from the MapKit framework and when iOS 7 launches, we’ll begin adjusting the tutorials accordingly. [Read more…]

CLGeocoder and CLPlacemark Tutorial – How to Find Location Information

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Core Location is a powerful framework that allows your apps to use location information. Mixed with the MapKit, you can create some powerful location based apps. Yesterday I wrote a tutorial about creating a CLRegion so that you can monitor when you enter or exit that particular area and have your app respond accordingly, even when the app is closed.

Today, I want to cover two more of the classes available in Core Location. Today we will focus on the CLGeocode class along with the CLPlacemark class. The reason I combine both in this tutorial, along with the required CLLocationManager and CLLocationManagerDelegate is that the CLGeocode class requires CLPlacemark to make it useful. Likewise, the CLPlacemark, according to documentation, is typically created by a CLGeocoder object. [Read more…]

How to Use the CLRegion Class for Geofencing

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When iOS 5 launched in October 2011, one of the features that caught my attention was location based reminders. Location based reminders provided the ability to connect a specific reminder to a specific location. An example could be, written in English, “When I arrive at the supermarket, remind me to buy flowers for my wife” or “when I leave work, remind me to call Fred”. When you approach a supermarket a reminder pops up telling you to go get flowers or when I leave the office, I get a reminder to call someone on my way home. Although GPS/location features have been available for most generations of the iPhone, mixing that power with context can make your app very powerful.

Of course, geofencing isn’t only for the built in reminders app that shipped with iOS 5. Apple has opened it up for developers to access. Today, we’ll be looking at how to work with geofencing which specifically uses the CLRegion Class as well as the CLLocationManager. A good place to start, as always, is the class reference. If you are unsure how to understand class references, methods, passing messages, properties etc… then take a read of this post and return back when done. [Read more…]

NSUserDefaults Example App

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The NSUserDefaults Class allows you to save settings of your app so that when the user closes the app or perhaps reboots their iOS device, the settings you set are retained. A quick example could be a maps app that lets you set it to show distances in Miles or Kilometers.

Before I continue, I want to point out that if you want to share settings across devices then you need to look at storing preferences in iCloud.

In todays tutorial I want to show a quick demonstration of how NSUserDefaults works and how you create the object as well as save data. I will also show you how to retrieve the data so that your app can load up with the settings the user selected.

Various types of data can be stored in NSUserDefaults which includes NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. Typically you would wrap a UIImage in to NSData to store in NSUserDefaults. Of course, you can also use other options to store data such as CoreData, but NSUserDefaults is a quick and simple way to store small amounts of data with just a few lines of code.

Lets begin by creating a new Single View application in Xcode. We then need to add a few things to the storyboard. Although you can follow this tutorial step by step, perhaps you could also experiment with your own ideas. The storyboard below has two views. The standard View Controller on the left that is set up when you create a Single View App. The second is a Table View Controller. I chose a Table View Controller because this is how I typically see settings views arranged. Of course, it isn’t essential that you use a Table View Controller for a settings view.

NSUserDefaults-Tutorial-Storyboard [Read more…]

How to use the iPhone Digital Compass in your App – CLHeading Tutorial

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iOS devices have several sensors built in that you can make use of in your app. One of them is the digital compass which is also known as a magnetometer. In todays tutorial I want to show you how how you can access the data so that you can use it in your app. The app will be very simple and will just use 8 UILabels with 4 of them being updated with various values.

headingTo begin with, create a new project in Xcode and choose a Single View Application. If you are not sure how to do this, take a look at my post called Setting up your First iOS Xcode Project which will get you to a fresh start and ready to create the app.

The next step is to drag our 8 UILabels. Put four of them down the left side of the screen and the other four down the right side as pictured here (aligning the text on the right hand labels to the left). Change the names to something like seen in the screen shot. You do not have to set the right hand set at zeros… anything will do, including blank UILabels.

Next, click on the middle Editor button (top right) to create a split to allow two files to be opened. On the left, click the Storyboard. The ViewController header file should then appear on the right.

At the top of the header file, import CoreLocation and also add the CLLocationManagerDelegate as follows:

#import 

@interface ViewController : UIViewController

The first of these two lines indicates that we will be using some of the CoreLocation framework. The allows this ViewController to receive updates when they are available. [Read more…]

How to Make didUpdateLocations Compatible with iOS 5 and iOS 6

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A popular method used from the CLLocationManagerDelegate protocol is – (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation which allows your app to receive updates when any location changes are detected. The new location details were stored in the newLocation which is a CLLocation.

When iOS 6 launched, that method was deprecated with a suggestion to use a newer version called – (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations or in short locationManager:didUpdateLocations:.

This quick tutorial has been created to explain how to handle a deprecated method, what should be done about it and where you can find out more details about the changes. If you want to know how to use the newer locationManager:didUpdateLocations: method then take a look at the didUpdateLocations tutorial that explains how to work with the NSArray provided by that method.

deprecated-method [Read more…]