Mastering images

There are two concepts that we must cover in this book before finishing this chapter about images. As you know, the images can be placed in multiple folders depending on the density of the screen—from low-density drawable-ldpi to high-density drawable-hdpi, extra extra-extra high-density drawable-xxxhdpi, and possibly more in the future. When we do this, we need to consider whether we want top quality images in all screens or a light APK. Replicating images will increase the size of our installer. This problem will disappear with the following component introduced in Android 5.0.

Vector drawables

These drawables are based on vector graphics; vector graphics can be scaled up and scaled down without losing any quality. With this, we just need a single drawable, and it will have excellent quality no matter the screen we use for it, be it an Android watch or an Android TV.

Vector drawables are defined in the same way that we define a shape—in an XML file. This is a simple vectordrawable...