How can I print messages (like a flag) to the Eclipse console (or log) when developing and debugging an Android app
5 Answers
Rather than trying to output to the console, Log will output to LogCat which you can find in Eclipse by going to: Window->Show View->Other…->Android->LogCat
Have a look at the reference for Log.
The benefits of using LogCat are that you can print different colours depending on your log type, e.g.: Log.d prints blue, Log.e prints orange. Also you can filter by log tag, log message, process id and/or by application name. This is really useful when you just want to see your app's logs and keep the other system stuff separate.
System.out.println() also outputs to LogCat. The benefit of using good old System.out.println() is that you can print an object like System.out.println(object) to the console if you need to check if a variable is initialized or not.
Log.d, Log.v, Log.w etc methods only allow you to print strings to the console and not objects. To circumvent this (if you desire), you must use String.format.