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HKSampleQuery Tutorial and Examples

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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…]

Reading Characteristic Data from HealthKit

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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…]

How to Setup Apple HealtKit in Your App

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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…]

HealthKit Tutorial – How to Write Weight Data with Swift

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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…]

HealthKit Tutorial – How to Fetch Weight Data with Swift

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In the last tutorial here I showed you how to create a line graph with PaintCode. In this tutorial we’ll use that line graph to plot some data. To do this we’ll get body mass (weight) data from HealthKit and plot it on the graph. By the end of this tutorial, you’ll see that although it was great to fetch the data from HealthKit and plot it on a graph, the app isn’t really that useful. In part 3, we will add more features that allow you to write data to HealthKit.

You can begin by downloading the basic tutorial where we left off last time found here.

Allowing the Points and Colours to Be Changed

As the current tutorial stands you can only display a static graph which is really of no use. Lets begin adding in the modifications that allow us to adjust the points and colours as needed.

To allow changes to be made we need to make a few modifications to the LineView class. We need to create some public variables. Open up LineView.swift and add the following just below the class definition:

//// Set the UIColors here. Defaults are .red and .gray
public var lineColour = UIColor .red
public var pointColour = UIColor .red
public var horizontalLineColour = UIColor .gray

//// The value of the top line on the graph (defaulted to 10)
public var height : CGFloat = 10.0

//// point0 is on the far left of the graph.
public var point0 : CGFloat = 8.0
public var point1 : CGFloat = 1.0
public var point2 : CGFloat = 2.0
public var point3 : CGFloat = 3.0
public var point4 : CGFloat = 4.0
public var point5 : CGFloat = 5.0
public var point6 : CGFloat = 6.0

//// Linewidth is defaulted to 2.0
public var lineWidth : CGFloat = 2.0

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