One of the most requested enhancements for the Random Contact App is for a way to filter contacts with the custom contact picker that is used in it. Since it seemed like a good reusable component, I added the module named MultiContactPicker along with the rearchitecture of my Andorid library project lib-aeApps.

Lets see how to add a filter for a RecyclerView in an Android app.

I migrated an Android app to AndroidX with the help of the Refactor option from Android Studio. After all the references in the java files were updated, I ran into the below error when I tried running my app.

  android.view.InflateException: Binary XML file line #2 in <>: Error inflating class androidx.constraintlayout.ConstraintLayout  
    Caused by: android.view.InflateException: Binary XML file line #2 in <>: Error inflating class androidx.constraintlayout.ConstraintLayout  
    Caused by: java.lang.ClassNotFoundException: androidx.constraintlayout.ConstraintLayout  

After a bit of head scratching and internet search, I was able to fix it by simply changing the declaration in the layout XML file. androidx.constraintlayout.ConstraintLayout to androidx.constraintlayout.widget.ConstraintLayout

I was expecting atleasst the IDE to throw an error, but had to find and fix it the hard way.

For no reason, I was reminded of a simple code snippet to swap (interchange) two numbers that I had discovered in my early programming days. I may have used it once or twice in my 10 years of being a professional software developer.

Swapping two numbers is a common use case when working with some algorithms and the like.