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Android Build a Simple Android App (2014) Improving Our Code Adding More Colors

Keishi Mii
Keishi Mii
3,122 Points

App keeps crashing after the step where the background should be switching colors randomly

I have followed the video exactly, but when I try to run the app it will just force exit the application instead of switching colors.

2 Answers


Can you please post the code of the activity which is causing the application crash as well as some logcat output?


Martin Georgiev
Martin Georgiev
13,541 Points


I have the same issue as well. After adding an Id to the RelativeLayout and trying to change it dynamically my app crashes. I receive the following error: "Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.RelativeLayout" showing the error on line 23 where I have: final RelativeLayout relativeLay = (RelativeLayout) findViewById(R.id.relativeLay);

I double-checked the code provided by the tutorial and what I have, Id, classes, methods etc...

update: I moved back several steps and tried to run the app without any color related code. It turns out that as soon as I put an ID on the RelaviteLayout the app crashes.