Log

public final class Log
extends Object

java.lang.Object
   ↳ android.util.Log

API for sending log output.

Generally, you should use the Log.v(), Log.d(), Log.i(), Log.w(), and Log.e() methods to write logs. You can then view the logs in logcat.

The order in terms of verbosity, from least to most is ERROR, WARN, INFO, DEBUG, VERBOSE.

Tip: A good convention is to declare a TAG constant in your class: 

private static final String TAG = "MyActivity";
 and use that in subsequent calls to the log methods.

Tip: Don't forget that when you make a call like 

Log.v(TAG, "index=" + i);
 that when you're building the string to pass into Log.d, the compiler uses a StringBuilder and at least three allocations occur: the StringBuilder itself, the buffer, and the String object. Realistically, there