DevFright

Learning Programming

Moving on to Swift

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It’s been a while since I added tutorials to DevFright, but now that I have some work completed, it is time to get working again and creating some great and helpful tutorials for you. Due to that big announcement a bit ago at WWDC 2014, I have decided that I’ll now focus on providing Swift tutorials rather than continue the focus on Objective-C. I have thought about a mixture of both, but settled on just Swift as this is where Apple is now focussing on the coming months and years and it makes sense to switch over ready for when iOS 8 launches in a few months time.

If you have any specific tutorials you want to see, drop a note in the comments below and I’ll do my best to accommodate.

iOS Data Download Progress Bar Tutorial

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You have probably seen a number of times an app that shows the progress of a download. Today, we’ll look at one way how this is accomplished. In this tutorial I’ll show you how to create a progress bar that fills up as more data is downloaded. The data we’ll download will be an image downloaded from the internet.

iOS Progress Bar Tutorial

Lets begin by loading up Xcode and creating a Single View Application.

Call the project “Progress Bar” and leave the rest of the options as default. You can choose iPad or iPhone for this project although we’ll create it for the iPhone in this tutorial. When you get to the option on the next page asking if you want a GIT repository, you can either select or deselect it.

navigationWhen the project is ready to go, load up the storyboard by clicking on Main.storyboard in the navigation pane to the left. When the storyboard loads up, you will see just a single view that is currently empty. We need to add a few objects to it which will include a progress bar and an image view. All this simple app will do is load up a pre-defined URL and as the page loads, it will show the progress of the page load and when done, it will show the item on screen. [Read more…]

NSArray reverseObjectEnumerator Tutorial

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In the last tutorial, we looked at the sortedArrayUsingComparator method which allows you to run a comparison on objects in an array and rearrange the objects in the array. In this tutorial we will look at a simple method which can be used to reverse the order of the contents of an array. Just be aware that this tutorial is quite brief as the code is relatively simple to use… it’s just a single line if you already have an NSArray to use.

Lets say you have 5 NSStrings which are a,b,c,d,e. When we iterate through these they will come out in the order of a,b,c,d,e. What if we want to show this information in a table view, but in reverse order? i.e., e,d,c,b,a. We do this with the reverseObjectEnumerator method of NSArray. [Read more…]

NSArray sortedArrayUsingComparator Tutorial

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Occasionally you will come across the need to re-order the contents of an NSArray. One reason could be that you want to put the contents of an NSArray in to a table view, but in a different order to what is currently in the NSArray. This tutorial shows one way (of many) of how this can be done.

The method we will look at in this tutorial is the sortedArrayUsingComparator: which is an instance method from the NSArray class. On first looks, this can look a little complicated, but if you take time to read through and see what is happening, it begins to make perfect sense. It also makes for quite clean code too.

arrayOfObjects = [arrayOfObjects sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        
    }];

[Read more…]

How to use a UISlider

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The UISlider is one of the default controls/objects that you can drag in to a storyboard on Xcode. The UISlider class is part of the UIKit framework. Today, we’ll have a look at how the slider works and give an example of how it might be used in one of your applications.

Look out for our next UISlider tutorial where we’ll look more in depth at the UISlider such as setting the value rather than getting the value as well as changing the sliders appearance. The second tutorial will be added to this section.

UISlider

A UISlider can be used for various purposes in your application such as a slider to control volume, screen brightness, set distances and many other cases. In todays tutorial I want to create a slider that sets the default zoom distance when zooming in to your current location on a map. [Read more…]

AVSpeechSynthesizer Tutorial – Letting Your App Speak Like Siri

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The AV Foundation Framework received a few extras when iOS 7 launched. One of those is the AVSpeechSynthesizer class which lets you have the device read out text in the voice of Siri.

The class is quite small in that it only has 4 methods and 3 properties which are:

Synthesizing Speech
€“ speakUtterance:
Controlling Speech Synthesis
€“ continueSpeaking
€“ pauseSpeakingAtBoundary:
paused property
speaking property
€“ stopSpeakingAtBoundary:
Managing the Delegate
delegate property [Read more…]

MKDirections Tutorial

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iOS 7 has given app developers the ability to add directions to their apps thanks to a new class in the Map Kit Framework called MKDirections. In this tutorial we will take a look at this class and create a simple app that lets you search for an address and calculate the distance as well as receive route-based directions from your current location. This tutorial will work on either an iOS device or on the simulator. [Read more…]

iOS 7 Background App Refresh Tutorial

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Background App Refresh is a new feature added to iOS 7. What it does is allows apps to quietly wake up and download content all while in the background.

Some of the built in Apple apps such as Mail, Contacts and the Calendar have always done this. When a new email arrives, you open the app and the email is there. Likewise, you add a contact on a remote device and it is automatically added to your contact list on your iPhone. On the other hand, all 3rd party apps could not do this. When notifications of a new email arrive, you open the app and then need to wait for syncronisation to happen. The same happens with apps like Evernote where your new notes are not downloaded until you open the app and sync it.

Background App Refresh changes this. iOS 7 developers can now add a few changes to their code and when done, iOS creates a schedule based on how often you use the app and then at intervals through the day, the app will quietly fetch data from your server so that when the user opens up the app, the syncronisation is already done.

Many apps have already taken advantage of this feature. This includes Dropbox, Evernote, Instapaper, Mailbox, Newsify and OmniFocus to name just a few.

Today, I want to show you how you can get your app to take advantage of this iOS 7 feature. [Read more…]

iBeacons Tutorial for iOS with CLBeaconRegion and CLBeacon

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Updated to Swift. Please visit here for the tutorial using Swift.

At WWDC earlier this year (2013) Apple announced iOS 7. Along with that announcement we heard of new API called iBeacons. iBeacons is a technology that uses transmitters and receivers which can let your iOS device know how far you are away from a beacon. One device acts as the transmitter and the other is a receiver.

iBeacon transmitters can either be a dedicated hardware device running Bluetooth 4.0 LE or you can configure a compatible iPhone or iPad to act as a transmitter. The receiving device is a compatible iPhone or iPad that can receive Bluetooth 4.0 LE. Compatible devices include the iPhone 4S and newer and the iPad 3 and newer (including iPad mini).

To give an example of what you could use iBeacons for, think of a group of museums managed by a single company. Each room in each of the museums would have an iBeacon transmitter placed in them. Each beacon is configured with settings or what Apple refers to as an identity. If you are running an app provided by the museum, each time you enter the museum you will be presented with information which changes depending on what room you are in. [Read more…]

NSNotificationCenter Tutorial

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NSNotificationCenter is one way you can communicate with other objects in your project. Alternatives include KVO and delegates. Rather than go in to all the details and comparisons of each and when you might opt for a delegate model vs NSNotificationCenter, what I will quickly say is that if you want to simply share a message that a job has completed and perhaps have several other classes listening out then NSNotificationCenter might be the best option for you.

In todays example we are going to create a simple app that lets you search for an address or point of interest on a map. When that search is complete, a pin or several pins will be dropped on the map with the appropriate details for a callout to pop up when a pin is tapped on. [Read more…]