Designing for Android: Screens
It seems overwhelming when you consider that there are dozens of devices currently available with the Android OS, and even more are on the way. Each device has slightly different screen properties. But freak out not, we’re going to simplify it.
Let’s take a look at some Android devices and their properties:
For every screen, there are 3 important properties related to its size:
- screen size – the actual physical screen size measured as the screen’s diagonal (e.g., 3.7”)
- resolution – the total number of physical pixels on a screen (e.g., 480x800px)
- density – the quantity of pixels within a physical area of a screen (e.g., 240dpi)
First of all, when designing we only focus on the densities and the screen sizes. We leave out the resolutions (although there are rare cases when we also take resolutions into account).
The densities and screen sizes are both split into four groups:
- screen sizes:
- small – around 2.5”
- normal – around 4”
- large – around 5.5”
- extra large – around 8”
- densities:
- low – around 120dpi (ldpi)
- medium – around 160dpi (mdpi)
- high – around 240dpi (hdpi)
- extra high – around 320dpi (xhdpi)
The screen sizes combined with the screen densities give us a total of 16 virtual groups of devices (each with several supported resolutions). I don’t want to bother with them, just yet. But if you’re curious, take a look at Supporting Multiple Screens (Table 2.)
Let’s boil it down to 2 groups of devices we usually target:
- handsets – small or normal screen size
- tablets – large or extra large screen size
These two differ basically in the layout – by how and where the controls are placed. As there’s more space on tablets, you will probably want to use a sidebar, more buttons, larger lists and even windows. You obviously cannot do that for a handset device.
You usually only need two sets of layouts per group: one for portrait and one for landscape. If you’re only targeting the handset devices (small and normal screen sizes), you only need to make the two.
Once you have the layout ready, you proceed to drawing. In the drawing phase, the densities come into play. That is covered in Designing for Android: Densities.
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