Apps are becoming increasingly important in designing for the challenges of later life and here Interaction Designer Richard Child from Grid North Design talks about three important points to consider in app design.
1. Follow the OS guidelines
Users are familiar with the navigation, interaction and UI elements of an OS, so it’s important that you read and follow the OS guidelines. Following the guidelines will ensure that your design remains consistent, and is easy to navigate and use.
It will also ensure that your app doesn’t get rejected during the app approval process.
The two most popular mobile operating systems are Apple iOS and Google Android. Google will soon be launching a new design language called “Material Design”.
See the links below for reference.
2. Design for a range of screen sizes and densities
Your app will be used on a range of screen sizes and densities. So it’s important that the experience is consistent, no matter what the device. Understanding screen density can be confusing, so let’s dive in!
To explain screen density, I’m going to use iOS as an example. Screen sizes are measured in points, and then the points are rendered into pixels, at a scale factor dependent on the ppi (pixels per inch) or pixel density of the device.
“Points are multiplied by a scale factor to get pixels. Higher scale factors result in higher level of detail. Typical scale factors are 1x, 2x and 3x.” – PaintCode
The original iPhone had a physical screen size of 3.5 inches, or 320 x 480 points, and a density of 163 ppi (1x). So the size of the screen is 320 x 480 pixels. Whereas the iPhone 4 has the same physical screen size, but a higher density of 326 ppi (2x). So the size of the screen is 640 x 960 pixels.
Below is a quick reference to make it easier. I’ve included all iPhone models which will be supported in iOS 8.
iPhone 4S renders @2x = 640 x 960 pixels
iPhone 5, 5C and 5S render @2x = 640 x 1136 pixels
iPhone 6 renders @2x = 750 x 1334 pixels
iPhone 6 Plus renders @3x = 1242 x 2208 pixels
When designing your app, it’s important to use the correct screen size in pixels, and ensure your design is consistent across all supported devices.
The above information relates to iOS. If you’re designing for Android, it’s important to read the OS guidelines.
3. Design for touch
We operate our smartphones with our fingers and thumbs, which are a lot less precise than a mouse. When designing your app, be aware that all tappable controls need to be big enough, so your app doesn’t frustrate users.
Luckily, the OS guidelines provide you with a reference. Apple says that all touch targets for iOS should be 44 x 44 points, whilst Google says 48 dp for Android.
Richard is currently an Interaction Designer at Grid North. Previously he worked at Cabify, a Spanish startup that designs and develops apps for personal transportation. Today, Cabify is available in Spain, Chile, Mexico and Peru. It’s had more than 100,000 downloads of its apps globally since launch.
Richard was a judge for Designing for the Future in 2012.