public
final
class
Log
extends Object
java.lang.Object | |
↳ | android.util.Log |
API for sending log output.
Generally, use the Log.v() Log.d() Log.i() Log.w() and Log.e() methods.
The order in terms of verbosity, from least to most is ERROR, WARN, INFO, DEBUG, VERBOSE. Verbose should never be compiled into an application except during development. Debug logs are compiled in but stripped at runtime. Error, warning and info logs are always kept.
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 is also another buffer allocation and copy, and even more pressure on the gc. That means that if your log message is filtered out, you might be doing significant work and incurring significant overhead.
Constants | |
---|---|
int |
ASSERT
Priority constant for the println method. |
int |
DEBUG
Priority constant for the println method; use Log.d. |
int |
ERROR
Priority constant for the println method; use Log.e. |
int |
INFO
Priority constant for the println method; use Log.i. |
int |
VERBOSE
Priority constant for the println method; use Log.v. |
int |
WARN
Priority constant for the println method; use Log.w. |
Public methods | |
---|---|
static
int
|
d(String tag, String msg, Throwable tr)
Send a |
static
int
|
d(String tag, String msg)
Send a |
static
int
|
e(String tag, String msg)
Send an |
static
int
|
e(String tag, String msg, Throwable tr)
Send a |
static
String
|
getStackTraceString(Throwable tr)
Handy function to get a loggable stack trace from a Throwable |
static
int
|
i(String tag, String msg, Throwable tr)
Send a |
static
int
|
i(String tag, String msg)
Send an |
static
boolean
|
isLoggable(String tag, int level)
Checks to see whether or not a log for the specified tag is loggable at the specified level. |
static
int
|
println(int priority, String tag, String msg)
Low-level logging call. |
static
int
|
v(String tag, String msg)
Send a |
static
int
|
v(String tag, String msg, Throwable tr)
Send a |
static
int
|
w(String tag, Throwable tr)
|
static
int
|
w(String tag, String msg, Throwable tr)
Send a |
static
int
|
w(String tag, String msg)
Send a |
static
int
|
wtf(String tag, String msg)
What a Terrible Failure: Report a condition that should never happen. |
static
int
|
wtf(String tag, Throwable tr)
What a Terrible Failure: Report an exception that should never happen. |
static
int
|
wtf(String tag, String msg, Throwable tr)
What a Terrible Failure: Report an exception that should never happen. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
int ASSERT
Priority constant for the println method.
Constant Value: 7 (0x00000007)
int DEBUG
Priority constant for the println method; use Log.d.
Constant Value: 3 (0x00000003)
int ERROR
Priority constant for the println method; use Log.e.
Constant Value: 6 (0x00000006)
int INFO
Priority constant for the println method; use Log.i.
Constant Value: 4 (0x00000004)
int VERBOSE
Priority constant for the println method; use Log.v.
Constant Value: 2 (0x00000002)
int WARN
Priority constant for the println method; use Log.w.
Constant Value: 5 (0x00000005)
int d (String tag, String msg, Throwable tr)
Send a DEBUG
log message and log the exception.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
int |
int d (String tag, String msg)
Send a DEBUG
log message.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
int e (String tag, String msg)
Send an ERROR
log message.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
int e (String tag, String msg, Throwable tr)
Send a ERROR
log message and log the exception.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
int |
String getStackTraceString (Throwable tr)
Handy function to get a loggable stack trace from a Throwable
Parameters | |
---|---|
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
String |
int i (String tag, String msg, Throwable tr)
Send a INFO
log message and log the exception.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
int |
int i (String tag, String msg)
Send an INFO
log message.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
boolean isLoggable (String tag, int level)
Checks to see whether or not a log for the specified tag is loggable at the specified level. The default level of any tag is set to INFO. This means that any level above and including INFO will be logged. Before you make any calls to a logging method you should check to see if your tag should be logged. You can change the default level by setting a system property: 'setprop log.tag.<YOUR_LOG_TAG> <LEVEL>' Where level is either VERBOSE, DEBUG, INFO, WARN, ERROR, ASSERT, or SUPPRESS. SUPPRESS will turn off all logging for your tag. You can also create a local.prop file that with the following in it: 'log.tag.<YOUR_LOG_TAG>=<LEVEL>' and place that in /data/local.prop.
Parameters | |
---|---|
tag |
String :
The tag to check. |
level |
int :
The level to check. |
Returns | |
---|---|
boolean |
Whether or not that this is allowed to be logged. |
Throws | |
---|---|
IllegalArgumentException |
is thrown if the tag.length() > 23. |
int println (int priority, String tag, String msg)
Low-level logging call.
Parameters | |
---|---|
priority |
int :
The priority/type of this log message |
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
Returns | |
---|---|
int |
The number of bytes written. |
int v (String tag, String msg)
Send a VERBOSE
log message.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
int v (String tag, String msg, Throwable tr)
Send a VERBOSE
log message and log the exception.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
int |
int w (String tag, Throwable tr)
Parameters | |
---|---|
tag |
String
|
tr |
Throwable
|
Returns | |
---|---|
int |
int w (String tag, String msg, Throwable tr)
Send a WARN
log message and log the exception.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log
|
Returns | |
---|---|
int |
int w (String tag, String msg)
Send a WARN
log message.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. It usually identifies
the class or activity where the log call occurs. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
int wtf (String tag, String msg)
What a Terrible Failure: Report a condition that should never happen.
The error will always be logged at level ASSERT with the call stack.
Depending on system configuration, a report may be added to the
DropBoxManager
and/or the process may be terminated
immediately with an error dialog.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. |
msg |
String :
The message you would like logged.
|
Returns | |
---|---|
int |
int wtf (String tag, Throwable tr)
What a Terrible Failure: Report an exception that should never happen.
Similar to wtf(String, String)
, with an exception to log.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. |
tr |
Throwable :
An exception to log.
|
Returns | |
---|---|
int |
int wtf (String tag, String msg, Throwable tr)
What a Terrible Failure: Report an exception that should never happen.
Similar to wtf(String, Throwable)
, with a message as well.
Parameters | |
---|---|
tag |
String :
Used to identify the source of a log message. |
msg |
String :
The message you would like logged. |
tr |
Throwable :
An exception to log. May be null.
|
Returns | |
---|---|
int |