Use logback-android for logging to external storage

(no WRITE_EXTERNAL_STORAGE permission necessary!)

app/build.gradle

@@ -23,5 +23,7 @@ dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     compile 'com.android.support:appcompat-v7:21.0.3'
     compile 'com.android.support:support-v4:21.0.3'
-    compile 'com.noveogroup.android:android-logger:1.3.5'
+//    compile 'com.noveogroup.android:android-logger:1.3.5'
+    compile 'com.github.tony19:logback-android-classic:1.1.1-3'
+    compile 'org.slf4j:slf4j-api:1.7.7'
 }

app/src/main/assets/logback.xml

@@ -0,0 +1,28 @@
+<configuration debug="true">
+
+    <appender name="STDOUT" class="ch.qos.logback.classic.android.LogcatAppender">
+        <!-- encoders are  by default assigned the type
+             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
+        <!--<file>/storage/emulated/0/Android/data/nodomain.freeyourgadget.gadgetbridge/files/gadgetbridge.log</file>-->
+        <file>${GB_LOGFILES_DIR}/gadgetbridge.log</file>
+        <lazy>true</lazy>
+        <!-- encoders are  by default assigned the type
+             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
+        <encoder>
+            <!--<pattern>%date %level [%thread] %logger{10} [%file:%line] %msg%n</pattern>-->
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{25} - %msg%n</pattern>
+            <!--<pattern>%date [%thread] %-5level %logger{25} - %msg%n</pattern>-->
+        </encoder>
+    </appender>
+
+    <root level="DEBUG">
+        <appender-ref ref="STDOUT" />
+        <appender-ref ref="FILE" />
+    </root>
+</configuration>

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java

@@ -3,6 +3,17 @@ package nodomain.freeyourgadget.gadgetbridge;
 import android.app.Application;
 import android.content.Context;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.FileOutputStream;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.core.CoreConstants;
+import ch.qos.logback.core.util.FileUtil;
+import ch.qos.logback.core.util.StatusPrinter;
+
 public class GBApplication extends Application {
     private static GBApplication context;
 
@@ -10,6 +21,29 @@ public class GBApplication extends Application {
         context = this;
     }
 
+    @Override
+    public void onCreate() {
+        super.onCreate();
+
+        setupLogFileDir();
+//        For debugging problems with the logback configuration
+//        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
+//         print logback's internal status
+//        StatusPrinter.print(lc);
+//        String dataDir = lc.getProperty(CoreConstants.DATA_DIR_KEY);
+//        String filename = FileUtil.prefixRelativePath(dataDir, "gadgetbridge.log");
+//        Logger logger = LoggerFactory.getLogger(GBApplication.class);
+    }
+
+    private void setupLogFileDir() {
+        File dir = getExternalFilesDir(null);
+        if (dir != null && !dir.exists()) {
+            dir.mkdirs();
+        }
+        // used by assets/logback.xml since the location cannot be statically determined
+        System.setProperty("GB_LOGFILES_DIR", dir.getAbsolutePath());
+    }
+
     public static Context getContext() {
         return context;
     }

app/src/main/resources/logback.xml

@@ -0,0 +1,25 @@
+<configuration debug="true">
+
+    <!--<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">-->
+        <!--&lt;!&ndash; encoders are  by default assigned the type-->
+             <!--ch.qos.logback.classic.encoder.PatternLayoutEncoder &ndash;&gt;-->
+        <!--<encoder>-->
+            <!--<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>-->
+        <!--</encoder>-->
+    <!--</appender>-->
+
+    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
+        <file>gadgetbridge.log</file>
+        <!-- encoders are  by default assigned the type
+             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
+        <encoder>
+            <!--<pattern>%date %level [%thread] %logger{10} [%file:%line] %msg%n</pattern>-->
+            <!--<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{25} - %msg%n</pattern>-->
+            <pattern>%date [%thread] %-5level %logger{25} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="debug">
+        <appender-ref ref="FILE" />
+    </root>
+</configuration>