How do I write outputs to the Log in Android?

I want to write some debugging output to the log to review it with logcat.

If I write something to System.out this is already displayed in logcat.

What is the clean way to write to the log and add levels and tags to my output?

Solution 1:

Look into android.util.Log. It lets you write to the log with various log levels, and you can specify different tags to group the output. For example

Log.w("myApp", "no network");

will output a warning with the tag myApp and the message no network.

Solution 2:

The Tag is just used to easily find your output, because the Output of LogCat can be sometimes very long. You can define somewhere in your class:

private static final String TAG = "myApp";

and use it when debugging

Log.v(TAG, "did something");

You can apply as well a Filter to only search for the tag.