Attributes – a quick summary

In the last few chapters, we have used and discussed quite a few different attributes. I thought it would be worth a quick summary and further investigation of a few of the more common ones.

Sizing using dp

As we know, there are thousands of different Android devices. Android uses density-independent pixels, or dp, as a unit of measurement to try and have a system of measurement that works across different devices. The way this works is by first calculating the density of the pixels on the device an app is running on.

Note

We can calculate density by dividing the horizontal resolution by the horizontal size, in inches, of the screen. This is all done on the fly on the device on which our app is running.

All we have to do is use dp in conjunction with a number when setting the size of the various attributes of our widgets. Using density-independent measurements, we can design layouts that scale to create a uniform appearance on as many different screens as possible...