android tips and tutorials

Back To Now app (iOS and Android releases) alvin October 24, 2019 - 12:33pm

My main project right now (through Valley Programming of Broomfield, Colorado) is porting my Back To Now mindfulness reminder app (formerly named Just Be) to run on both Android and iOS. It’s great to have a toolkit where I can write an app for Android and iOS using one set of code.

My “XOP” football game UI, v1.4 alvin July 13, 2019 - 8:24pm

The UI still needs a lot of work, but I like the idea of having an Inconceivable mode in the next version of my XO Play Android football game.

XO Play (Android football game) alvin July 3, 2019 - 7:13pm

XO Play is a “thinking man’s” football game that I created for Android devices. It’s for those of us who enjoy thinking about football strategy, of how to take advantage of our strengths and our opponents’ weaknesses, and how to call plays to win games. If you’ve ever watched a football game and thought, “I can call plays better than this guy,” XO Play is for you.

Version 1.4

Version 1.4 introduces four game levels you can choose from:

XO Play help text alvin June 29, 2019 - 5:38pm

This is the “help” text for my Android football game XO Play.

Changes in Version 1.4

Released on July 14, 2019, Version 1.4 introduces four new game levels:

Butter Knife alvin March 10, 2019 - 3:29pm

Butter Knife is an Android library that can help you get rid of all those ugly findViewById calls. Android Data Binding may be a better solution, but at the moment I prefer the tag/annotation approach of Butter Knife.

Notes on how to build and run an Android application from the command line alvin March 6, 2019 - 8:21pm

As a brief note to self, this is how I compiled/built an Android application (APK) from the MacOS command line and then ran it in an emulator. I include both my application- and system-specific notes, as well as the more generic commands I found at this URL:

Where is the Android SDK located on macOS? (setting ANDROID_HOME) alvin March 6, 2019 - 8:00pm

If you’re using macOS and need to know where (in what directory) the Android SDK is located, it is currently located here:


The sdkmanager and avdmanager and a few others are located in this directory:


The Android SDK platform tools bin directory is here:


I’m doing some things with Android from the command line tonight and learned that I needed to set ANDROID_HOME, and that’s when I dug into this.

~ March, 2019

Android Studio 3 Error: Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly alvin March 6, 2019 - 6:20pm

When I tried to open an Android project with Android 3 that I probably created with Android Studio 2 and haven’t worked on in about two years, I got this error message:

Android Dexter class: requesting permissions at runtime alvin February 26, 2019 - 7:53pm

I learned about the Android Dexter project today, which simplifies the process of requesting permissions at application runtime.