How do I enable disable log levels in Android

Question

I am having lots of logging statements to debug for example   Log v TAG   Message here    Log w TAG    WARNING HERE      while deploying this application on device phone i want to turn off the verbose logging from where i can enable disable logging

User · Answer

For me it is often useful being able to set different log levels for each TAG.

I am using this very simple wrapper class:

public class Log2 {

    public enum LogLevels {
        VERBOSE(android.util.Log.VERBOSE), DEBUG(android.util.Log.DEBUG), INFO(android.util.Log.INFO), WARN(
                android.util.Log.WARN), ERROR(android.util.Log.ERROR);

        int level;

        private LogLevels(int logLevel) {
            level = logLevel;
        }

        public int getLevel() {
            return level;
        }
    };

    static private HashMap<String, Integer> logLevels = new HashMap<String, Integer>();

    public static void setLogLevel(String tag, LogLevels level) {
        logLevels.put(tag, level.getLevel());
    }

    public static int v(String tag, String msg) {
        return Log2.v(tag, msg, null);
    }

    public static int v(String tag, String msg, Throwable tr) {
        if (logLevels.containsKey(tag)) {
            if (logLevels.get(tag) > android.util.Log.VERBOSE) {
                return -1;
            }
        }
        return Log.v(tag, msg, tr);
    }

    public static int d(String tag, String msg) {
        return Log2.d(tag, msg, null);
    }

    public static int d(String tag, String msg, Throwable tr) {
        if (logLevels.containsKey(tag)) {
            if (logLevels.get(tag) > android.util.Log.DEBUG) {
                return -1;
            }
        }
        return Log.d(tag, msg);
    }

    public static int i(String tag, String msg) {
        return Log2.i(tag, msg, null);
    }

    public static int i(String tag, String msg, Throwable tr) {
        if (logLevels.containsKey(tag)) {
            if (logLevels.get(tag) > android.util.Log.INFO) {
                return -1;
            }
        }
        return Log.i(tag, msg);
    }

    public static int w(String tag, String msg) {
        return Log2.w(tag, msg, null);
    }

    public static int w(String tag, String msg, Throwable tr) {
        if (logLevels.containsKey(tag)) {
            if (logLevels.get(tag) > android.util.Log.WARN) {
                return -1;
            }
        }
        return Log.w(tag, msg, tr);
    }

    public static int e(String tag, String msg) {
        return Log2.e(tag, msg, null);
    }

    public static int e(String tag, String msg, Throwable tr) {
        if (logLevels.containsKey(tag)) {
            if (logLevels.get(tag) > android.util.Log.ERROR) {
                return -1;
            }
        }
        return Log.e(tag, msg, tr);
    }

}

Now just set the log level per TAG at the beginning of each class:

Log2.setLogLevel(TAG, LogLevels.INFO);

User · Answer

Here is a more complex solution  You will get full stack trace and the method toString   will be called only if needed Performance   The attribute BuildConfig DEBUG will be false in the production mode so all trace and debug logs will be removed  The hot spot compiler has the chance to remove the calls because off final static properties    import java io ByteArrayOutputStream  import java io PrintStream  import android util Log   public class Logger        public enum Level           error  warn  info  debug  trace            private static final String DEFAULT TAG    Project        private static final Level CURRENT LEVEL   BuildConfig DEBUG   Level trace   Level info       private static boolean isEnabled Level l            return CURRENT LEVEL compareTo l   gt   0             static           Log i DEFAULT TAG   log level      CURRENT LEVEL name                private String classname   DEFAULT TAG       public void setClassName Class lt   gt  c            classname   c getSimpleName               public String getClassname             return classname             public boolean isError             return isEnabled Level error              public boolean isWarn             return isEnabled Level warn              public boolean isInfo             return isEnabled Level info              public boolean isDebug             return isEnabled Level debug              public boolean isTrace             return isEnabled Level trace              public void error Object    args            if  isError    Log e buildTag    build args               public void warn Object    args            if  isWarn    Log w buildTag    build args               public void info Object    args            if  isInfo    Log i buildTag    build args               public void debug Object    args            if  isDebug    Log d buildTag    build args               public void trace Object    args            if  isTrace    Log v buildTag    build args               public void error String msg  Throwable t            if  isError    error buildTag    msg  stackToString t               public void warn String msg  Throwable t            if  isWarn    warn buildTag    msg  stackToString t               public void info String msg  Throwable t            if  isInfo    info buildTag    msg  stackToString t               public void debug String msg  Throwable t            if  isDebug    debug buildTag    msg  stackToString t               public void trace String msg  Throwable t            if  isTrace    trace buildTag    msg  stackToString t               private String buildTag             String tag           if  BuildConfig DEBUG                StringBuilder b   new StringBuilder 20               b append getClassname                  StackTraceElement stackEntry   Thread currentThread   getStackTrace   4               if  stackEntry    null                    b append                       b append stackEntry getMethodName                     b append                       b append stackEntry getLineNumber                               tag   b toString              else               tag   DEFAULT TAG                       private String build Object    args            if  args    null                return  null             else               StringBuilder b   new StringBuilder args length   10               for  Object arg   args                    if  arg    null                        b append  null                      else                       b append arg                                               return b toString                         private String stackToString Throwable t            ByteArrayOutputStream baos   new ByteArrayOutputStream 500           baos toString            t printStackTrace new PrintStream baos            return baos toString              use like this   Loggor log   new Logger    Map foo       List bar       log error  Foo    foo   bar    bar      bad example  avoid something like this     log error  Foo       foo toString      bar     bar

User · Answer

We can use class Log in our local component and define the methods as v i e d  Based on the need of we can make call further  example is shown below       public class Log          private static boolean TAG   false          public static void d String enable tag  String message Object   args               if TAG              android util Log d enable tag  message args                     public static void e String enable tag  String message Object   args               if TAG              android util Log e enable tag  message args                     public static void v String enable tag  String message Object   args               if TAG              android util Log v enable tag  message args                       if we do not need any print s   at-all make TAG as false for all else      remove the check for type of Log  say Log d       as      public static void i String enable tag  String message Object   args               if TAG              android util Log i enable tag  message args           here message is for string and and args is the value you want to print

User · Answer

May be you can see this Log extension class  https   github com dbauduin Android-Tools tree master logs   It enables you to have a fine control on logs  You can for example disable all logs or just the logs of some packages or classes   Moreover  it adds some useful functionalities  for instance you don t have to pass a tag for each log

User · Answer

https   limxtop blogspot com 2019 05 app-log html Read this article please  where provides complete implement   For debug version  all the logs will be output  For release version  only the logs whose level is above DEBUG  exclude  will be output by default  In the meanwhile  the DEBUG and VERBOSE log can be enable through setprop log tag  lt YOUR LOG TAG gt   lt LEVEL gt  in running time

User · Answer

In my apps I have a class which wraps the Log class which has a static boolean var called  state    Throughout my code I check the value of the  state  variable using a static method before actually writing to the Log   I then have a static method to set the  state  variable which ensures the value is common across all instances created by the app   This means I can enable or disable all logging for the App in one call - even when the App is running   Useful for support calls     It does mean that you have to stick to your guns when debugging and not regress to using the standard Log class though     It s also useful  convenient  that Java interprets a boolean var as false if it hasn t been assigned a value  which means it can be left as false until you need to turn on logging  -

User · Answer

Another way is to use a logging platform that has the capabilities of opening and closing logs  This can give much of flexibility sometimes even on a production app which logs should be open and which closed depending on which issues you have for example    LumberJack Shipbook  disclaimer  I m the author of this package

User · Answer

In a very simple logging scenario  where you re literally just trying to write to console during development for debugging purposes  it might be easiest to just do a search and replace before your production build and comment out all the calls to Log or System out println   For example  assuming you didn t use the  Log   anywhere outside of a call to Log d or Log e  etc  you could simply do a find and replace across the entire solution to replace  Log   with    Log   to comment out all your logging calls  or in my case I m just using System out println everywhere  so before going to production I ll simply do a full search and replace for  System out println  and replace with    System out println    I know this isn t ideal  and it would be nice if the ability to find and comment out calls to Log and System out println were built into Eclipse  but until that happens the easiest and fastest and best way to do this is to comment out by search and replace   If you do this  you don t have to worry about mismatching stack trace line numbers  because you re editing your source code  and you re not adding any overhead by checking some log level configuration  etc

User · Answer

I took a simple route - creating a wrapper class that also makes use of variable parameter lists    public class Log          public static int LEVEL   android util Log WARN        static public void d String tag  String msgFormat  Object   args                if  LEVEL lt  android util Log DEBUG                        android util Log d tag  String format msgFormat  args                         static public void d String tag  Throwable t  String msgFormat  Object   args                if  LEVEL lt  android util Log DEBUG                        android util Log d tag  String format msgFormat  args   t                             other level logging functions snipped

User · Answer

There is a tiny drop-in replacement for the standard android Log class - https   github com zserge log  Basically all you have to do is to replace imports from android util Log to trikita log Log  Then in your Application onCreate   or in some static initalizer check for the BuilConfig DEBUG or any other flag and use Log level Log D  or Log level Log E  to change the minimal log level  You can use Log useLog false  to disable logging at all

User · Answer

A common way is to make an int named loglevel  and define its debug level based on loglevel   public static int LOGLEVEL   2  public static boolean ERROR   LOGLEVEL  gt  0  public static boolean WARN   LOGLEVEL  gt  1      public static boolean VERBOSE   LOGLEVEL  gt  4       if  VERBOSE  Log v TAG   Message here       Won t be shown     if  WARN  Log w TAG   WARNING HERE          Still goes through   Later  you can just change the LOGLEVEL for all debug output level

User · Answer

The better way is to use SLF4J API   some of its implementation   For Android applications you can use the following    Android Logger is the lightweight but easy-to-configure SLF4J implementation   lt  50 Kb   LOGBack is the most powerful and optimized implementation but its size is about 1 Mb  Any other by your taste  slf4j-android  slf4android

User · Answer

Stripping out the logging with proguard  see answer from  Christopher   was easy and fast  but it caused stack traces from production to mismatch the source if there was any debug logging in the file   Instead  here s a technique that uses different logging levels in development vs  production  assuming that proguard is used only in production  It recognizes production by seeing if proguard has renamed a given class name  in the example  I use  com foo Bar --you would replace this with a fully-qualified class name that you know will be renamed by proguard    This technique makes use of commons logging   private void initLogging         Level level   Level WARNING      try              in production  the shrinker obfuscator proguard will change the            name of this class  and many others  so in development  this            class WILL exist as named  and we will have debug level         Class forName  com foo Bar            level   Level FINE        catch  Throwable t               no problem  we are in production mode           Handler   handlers   Logger getLogger     getHandlers        for  Handler handler   handlers            Log d  log init    handler      handler getClass   getName             handler setLevel level

User · Answer

Log4j or slf4j can also be used as logging frameworks in Android together with logcat  See the project android-logging-log4j or log4j support in android

User · Answer

The Android Documentation says the following about Log Levels      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    So you may want to consider stripping the log Verbose logging statements out  possibly using ProGuard as suggested in another answer   According to the documentation  you can configure logging on a development device using System Properties   The property to set is log tag  lt YourTag gt  and it should be set to one of the following values  VERBOSE  DEBUG  INFO  WARN  ERROR  ASSERT  or SUPPRESS   More information on this is available in the documentation for the isLoggable   method   You can set properties temporarily using the setprop command   For example   C  android gt adb shell setprop log tag MyAppTag WARN C  android gt adb shell getprop log tag MyAppTag WARN   Alternatively  you can specify them in the file   data local prop  as follows   log tag MyAppTag WARN   Later versions of Android appear to require that  data local prop be read only   This file is read at boot time so you ll need to restart after updating it   If  data local prop is world writable  it will likely be ignored   Finally  you can set them programmatically using the System setProperty   method

User · Answer

You should use      if  Log isLoggable TAG  Log VERBOSE             Log v TAG   my log message

User · Answer

I created a Utility Wrapper which solves this problem   other common problems around Logging   A Debugging utility with the following features    The usual features provided by Log class wrapped around by LogMode s  Method Entry-Exit logs  Can be turned off by a switch Selective Debugging  Debug specific classes  Method Execution-Time Measurement  Measure Execution time for individual methods as well as collective time spent on all methods of a class    How To Use    Include the class in your project  Use it like you use android util Log methods  to start with  Use the Entry-Exit logs feature by placing calls to entry log  -exit log   methods at the beginning and ending of methods in your app    I have tried to make the documentation self suffiecient   Suggestions to improve this Utility are welcome   Free to use share   Download it from GitHub

User · Answer

The easiest way is probably to run your compiled JAR through ProGuard before deployment  with a config like   -assumenosideeffects class android util Log       public static int v           That will  mdash  aside from all the other ProGuard optimisations  mdash  remove any verbose log statements directly from the bytecode

[android] How do I enable/disable log levels in Android?

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