Android slf4j logger with logcat + file; logging to file and logcat on Android

app.gradle

//Add slf4j dependencies in gradle
dependencies {
   compile 'org.slf4j:slf4j-api:1.7.7'
   compile 'com.github.tony19:logback-android-core:1.1.1-3'
   compile 'com.github.tony19:logback-android-classic:1.1.1-3'
}

InitActivity.java

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class InitActivity {

  public InitActivity() {
      logger.debug("Activity loading....");
  }


  private static final Logger logger = LoggerFactory.getLogger(InitActivity.class);
}

logback.xml

<!-- Put this file in src/main/assets/logback.xml (your main assets folder) -->
<configuration>
    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
        <file>/sdcard/shant/shant.log</file> <!-- /sdcard/testFile.log -->
        <append>true</append>
        <encoder>
            <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="LOGCAT" class="ch.qos.logback.classic.android.LogcatAppender">
        <encoder>
            <pattern>%-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="DEBUG">
        <appender-ref ref="FILE" />
        <appender-ref ref="LOGCAT" />
    </root>
</configuration>