Learn How to Create iOS Apps
We looked previously at the basic HKSampleQuery and the HKAnchoredObjectQuery. Both provided ways to query samples in HealthKit and work with data that the user had provided permission for.
The next query we will look at is the HKStatisticsQuery. This query is particularly interesting to those who want to calculate sum, minimum, maximum, or average values.
Lets begin by downloading the project from where we left off last time.
[Read more…]Updated 21 March 2025 for iOS 18.
For a more modern version using SwiftUI to visualise the data, see How to Fetch and Display HealthKit Data with HKAnchoredObjectQuery
The HKAnchoredObjectQuery provides a useful way to keep tabs on what has changed for a particular sample type. It provides us with both the ability to receive a snapshot of data, and then on subsequent calls, a snapshot of what has changed. Alternatively you can create the initial snapshot of samples, and then continuously monitor as a long-running query which notifies you each time a new sample is added or when a sample is deleted.
For this tutorial we will continue on from an earlier tutorial, and add more functions that will allow us to test the HKAnchoredObjectQuery class. Go ahead and download the latest version of the project and open it in Xcode.
[Read more…]In the last tutorial we covered reading characteristic data from HealthKit. Characteristic data is read by accessing direct methods on the health store. These queries are simple because items like date of birth and biological sex do not typically change. However, there are many data types stored in Apple Health that do change such as step counts, heart rate, body mass, and so on. For these types of data Apple allows us to create queries so that we can fetch the data we want.
Many of your requests to HealthKit will be done by using a query. Queries allow you to fetch a snapshot of data from the HealthKit store. There are eight different types of queries that you have available to use with HealthKit. This tutorial will cover the HKSampleQuery. We will look at each other type of query in separate posts. [Read more…]
For todays tutorial we will look at reading characteristic data from HealthKit. This is one of several ways in which we can read data, with the other ways being queries and long-running queries. We will investigate queries and long-running queries at another time.
Direct method calls can be used to the HKHealthStore to read characteristic data. These items stored in HealthKit do not require a query to be made. These are characteristic types of data such as sex, date of birth, and blood type, to name a few. The reason for this is that these types of data do not change over time. For example, your birthday remains constant.
You can access characteristic data directly through the health store. In a previous tutorial we covered how to setup Apple HealthKit. We will continue on from this project, which you can download here.
In that previous tutorial we requested permissions for stepCount and biologicalSex. Out of these two, biologicalSex is the only one which is characteristic data. We will look at how we can request this data from Apple HealthKit. [Read more…]
Since the launch of the Apple Health app and HealthKit framework in September 2014, iPhone and Apple Watch users have had a simple way of storing all of their health related data. In Apple’s words “HealthKit provides a central repository for health and fitness data on iPhone and Apple Watch”.
Although the Health app has a simple UI and can provide health and fitness data to the user, the real power is made available when app developers interface with the HealthKit framework and build apps that specialise in certain areas.
Todays tutorial will focus on adding HealthKit to your app and preparing your app to be able to write and query data from Apple Health. This is part of a series of HealthKit tutorials that we will make with the next tutorial focusing on querying data. In future posts we will look at the HKSampleQuery, HKStatisticsCollectionQuery, to name a couple. [Read more…]
In a previous tutorial, we looked at how to send a local notification. Using the basic code provided by Apple you can trigger notifications to fire almost immediately as well as at a specified date and time in the future. In this tutorial we’ll expand on this by looking at the associated delegate protocol; UNUserNotificationCenterDelegate; which allows us to detect which notification was swiped, and also detect when a notification is triggered when the app is in the foreground. To begin, download the project from here which we created in the last tutorial.
[Read more…]Updated to work with Xcode 13 and Swift 5.
The UserNotifications framework was introduced with iOS 10 and has been designed to work with iOS, tvOS, and watchOS, and replaces UILocalNotification from the UIKit framework. UILocalNotification and other variants were deprecated in iOS 10.
If you want to send a notification to the lock screen of an iPhone, using the UserNotifications framework is now the way to go.
In this tutorial we’ll look at how to get a basic notification on to the lock screen. In the next tutorial, we’ll look at all the other parts that we do not cover here such as being able to put a notification on screen based on location; without using the CoreLocation framework, and we’ll also look at how to handle specific notifications so that we know which one was tapped or swiped.
[Read more…]
When needing to put an alert on the view of your app the previous way to handle this was with a UIAlertView or UIActionSheet. Both of these were deprecated in iOS 8 which means if you are targeting newer versions of iOS, which you should be in many cases, you now need to use UIAlertController. If you want to see how alerts worked in iOS 8 or below, you can find an example in the Location Authorization tutorial we made a few years ago.
UIAlertController became available in the iOS 8.0 SDK. Rather than go through the differences between this class and the previously used classes we’ll just look at what can be done with the UIAlertController. [Read more…]
In the final part of this tutorial series we will make some slight adjustments to the graph, and then provide the ability to record your weight in HealthKit.
You can either jump back to the beginning where we created a line graph with Paintcode, start on step 2, or begin here by downloading the project as we left it at the end of the last tutorial. [Read more…]
When iOS 10.3 was launched it provided developers with the ability to let users change the icon in the app. In this fairly short tutorial I’ll show you how it’s done.
To begin, create a new project in Xcode. An iOS/Single View is a good place to start. Make sure you select Swift as the language. The same function can also be created with Objective-C, but this tutorial focuses on the Swift way.
We now need add some keys to Info.plist for the app. In particular, add the following: [Read more…]