Recolouring / modifying multi-layer drawables dynamically in Android

Often when creating interfaces in Android, it can be more efficient to have a single .xml drawable and recolouring it according to requirements, instead of trying to include all possible colours in advance. Similarly, it can be more efficient to replace the drawable used inside another drawable dynamically. However, if this needs to be done multiple times within one drawable it becomes a bit more complex, as any modifications will affect the entire drawable.

This post is also available as a Gist.

Continue reading →

Dynamically preventing scrolling on selected ViewPager pages

ViewPagers are an extremely powerful UI tool that by default can be swiped left and right freely. In some cases however, it can be useful to prevent the user swiping in certain directions on certain pages, i.e. a “LockableViewPager”. For example, the first 2 pages might have to be passed programmatically, and then all other pages can be navigated between freely.

This article will implement determining and changing at any time the current permitted swipe direction(s) (left, right, both, neither) using a custom ViewPager, concluding with a full use case. The end result of this article is also available as a Gist.

Continue reading →

Generic SharedPreferences Utility Class

Recently, a project required both backed up and non-backed up SharedPreferences, as well as an easy way to read and write these values. The following class was created with this functionality, using generics in Kotlin for practice. This post will walkthrough some of the key features, the finished code is also available as a Gist.

Continue reading →