Writing our first Java code
So, we now know the code that will output to logcat or the user's screen. But where do we put the code? To answer this question, we need to understand that the onCreate
method in HelloWorldActivity.java
executes as the app is preparing to be shown to the user. So, if we put our code at the end of this method, it will run just as the user sees it. Sounds good.
Tip
We know that to execute the code in a method, we need to call it. We have wired our buttons up to call a couple of methods, topClick
and bottomClick
. Soon, we will write these methods. But who or what is calling onCreate?
The answer to this mystery is that Android itself calls onCreate
in response to the user clicking the app icon to run the app. In Chapter 6 ...
Get Android Programming for Beginners - Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.