How do you usually Tag log entries? (android)

Question

I assume most of you are aware of android.util.Log All logging methods accept 'String tag' as a first argument.

And my question is How do you usually tag your logs in your applications? I've seen some hardcode like this:

public class MyActivity extends Activity {
    private static final String TAG = "MyActivity";
    //...
    public void method () {
        //...
        Log.d(TAG, "Some logging");
    }
}

This doesn't look nice because of many reasons:

• You can tell me this code doesn't have hardcode, but it does.
• My application could have any number of classes in different packages with the same name. So it would be hard to read the log.
• It isn't flexible. You always have put a private field TAG into your class.

Is there any neat way to get a TAG for a class?

Answer 1

AndroidStudio has a logt template by default (you can type logtand press tab to have it expand to a sinppet of code) . I recommend using this to avoid copy pasting the TAG definition from another class and forgetting to change the class you're referring to. The template expands by default to

private static final String TAG = "$CLASS_NAME$"

To avoid using the old class name after refactoring you could change that to

private static final String TAG = $CLASS_NAME$.class.getSimpleName();

Remember to check the "Edit variables" button and make sure that the CLASS_NAME variable is defined to use the className() Expression and has "Skip if defined" checked.

Answer 2

I use a TAG, but I initialise it like this:

private static final String TAG = MyActivity.class.getName();

This way when I refactor my code the tag will also change accordingly.

Answer 3

At the expense of updating these strings when I move code between methods or rename methods, I like doing the following. Philosophically it also seems to be better to keep "location" or "context" in the tag, not the message.

public class MyClass {

    // note this is ALWAYS private...subclasses should define their own
    private static final LOG_TAG = MyClass.class.getName();

    public void f() {
        Log.i(LOG_TAG + ".f", "Merry Christmas!");
    }

}

The benefit here is that you can filter out a single method even if the content isn't static, e.g.

Log.i(LOG_TAG + ".f", String.valueOf(new Random().nextInt()));

The only drawback is that when I rename f() to g() I need to keep that string in mind. Also, automatic IDE refactoring won't catch these.

For a while I was a fan of using the short class name, I mean LOG_TAG = MyClass.class.getSimpleName(). I found them harder to filter in the logs because there was less to go on.

Answer 4

You could use this.toString() to get a unique identifer for the specific class in which you print to the log.

Answer 5

It is a very old question, but even thought an updated answer for July 2018 it is more preferable to use Timber. In order to Log the correct logging, errors and warns can be send to third party crash libraries, such as Firebase or Crashlytics.

In the class that implements Application you should add this:

@Override
public void onCreate() {
    super.onCreate();
    if (BuildConfig.DEBUG) {
        Timber.plant(new Timber.DebugTree());
    } else {
        Timber.plant(new CrashReportingTree());
    }
}

/** A tree which logs important information for crash reporting. */
private static class CrashReportingTree extends Timber.Tree {
    @Override protected void log(int priority, String tag, String message, Throwable t) {
        if (priority == Log.VERBOSE || priority == Log.DEBUG) {
            return;
        }

        FakeCrashLibrary.log(priority, tag, message);

        if (t != null) {
            if (priority == Log.ERROR) {
                FakeCrashLibrary.logError(t);
            } else if (priority == Log.WARN) {
                FakeCrashLibrary.logWarning(t);
            }
        }
    }
}

Do not forget Timber dependency.

implementation 'com.jakewharton.timber:timber:4.7.1'

Answer 6

Go to Android Studio -> preference -> Live Templates -> AndroidLog then select Log.d(TAG, String).

In Template text replace

android.util.Log.d(TAG, "$METHOD_NAME$: $content$");

with

android.util.Log.d("$className$", "$METHOD_NAME$: $content$");

Then click Edit variables and enter className() in the Expression column next to the className Name column.

Now when you type the shortcut logd it will put

Log.d("CurrentClassName", "currentMethodName: ");

You dont need to define a TAG anymore.