Android best logger for logging into file

Question

What is the best logger framework which perfectly use in Android system for logging text into file?

I tried to use SLF4J-android but I got an exception

04-29 12:58:57.604: E/AndroidRuntime(372): java.lang.NoClassDefFoundError: org.slf4j.LoggerFactory

here is my code:

public class Main extends TabActivity {
    private static final Logger log = LoggerFactory.getLogger(Main.class); 

I added the slf4j-android-1.6.1-RC1.jar into build path

What will be the problem?

Answer 1

slf4j-android only supports logging to logcat and thus omits several classes from the regular SLF4J jar. If you want to use logback to log to a file, you need the API jar (not slf4j-android) and logback-android. You're looking for the FileAppender or RollingFileAppender.

Instructions:

1. Add slf4j-api-<version>.jar and logback-android-<version>.jar to your classpath.

2. Create the file assets/logback.xml in your project (or use the AndroidManifest.xml...see example), containing the following configuration:

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.FileAppender">
    <file>/sdcard/testFile.log</file>
    <append>true</append>
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>
        
  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

Note: Since the specified path is on SD, make sure to use WRITE_EXTERNAL_STORAGE permission. You can instead specify a different path where you already have write permissions.

Your Java code, which contains the SLF4J logging calls, now logs all events at or above the DEBUG level to the /sdcard/testFile.log.

Answer 2

Make a folder named "libs" and put the jar inside that folder.