Unfortunately, learning to build for Android is one of the more difficult areas to begin with. Building Android apps needs knowledge of not only Java (a difficult language in and of itself), but also project structure, the Android SDK, XML, and other topics.

It would take 3-4 months to learn essential Java skills that lead to android programming. It will take 1 to 1.5 years to master the same. In conclusion, if you are a beginner, it is anticipated that it will take you roughly two years to gain a good grasp and begin developing for Android.