Make file-logging configurable

app/src/main/assets/logback.xml

@@ -10,11 +10,12 @@
 
     <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
         <file>${GB_LOGFILES_DIR}/gadgetbridge.log</file>
+
         <lazy>true</lazy>
         <!-- encoders are  by default assigned the type
              ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
         <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
-            <fileNamePattern>gadgetbridge-%d{yyyy-MM-dd}.log.zip</fileNamePattern>
+            <fileNamePattern>${GB_LOGFILES_DIR}/gadgetbridge-%d{yyyy-MM-dd}.log.zip</fileNamePattern>
             <maxHistory>10</maxHistory>
         </rollingPolicy>
         <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">

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

@@ -7,7 +7,9 @@ import android.bluetooth.BluetoothAdapter;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
+import android.preference.PreferenceManager;
 import android.support.v4.app.NotificationCompat;
 
 import org.slf4j.Logger;

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

@@ -2,6 +2,11 @@ package nodomain.freeyourgadget.gadgetbridge;
 
 import android.app.Application;
 import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.File;
 
@@ -16,23 +21,37 @@ public class GBApplication extends Application {
     public void onCreate() {
         super.onCreate();
 
-        setupLogFileDir();
+        setupLogging();
 //        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() {
+    public static boolean isFileLoggingEnabled() {
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(GBApplication.getContext());
+        return prefs.getBoolean(GBApplication.getContext().getString(R.string.pref_log_to_file), false);
+    }
+
+    private void setupLogging() {
+        if (isFileLoggingEnabled()) {
             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());
+        } else {
+            System.setProperty("GB_LOGFILES_DIR", "/dev/null"); // just to please logback configuration, not used at all
+            try {
+                ch.qos.logback.classic.Logger root = (ch.qos.logback.classic.Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+                root.detachAppender("FILE");
+            } catch (Throwable ex) {
+                System.out.println("Error removing logger FILE appender");
+                ex.printStackTrace();
+            }
+        }
     }
 
     public static Context getContext() {

app/src/main/res/values/strings.xml

@@ -101,5 +101,7 @@
     <string name="pref_header_vibration_count">Vibration Count</string>
 
     <string name="title_activity_sleepmonitor">Sleep Monitor</string>
+    <string name="pref_log_to_file">LogToFile</string>
+    <string name="pref_write_logfiles">Write Log Files (needs restart)</string>
 
 </resources>

app/src/main/res/xml/preferences.xml

@@ -60,4 +60,10 @@
             android:key="pref_key_miband"
             android:title="@string/preferences_miband_settings" />
     </PreferenceCategory>
+
+    <CheckBoxPreference
+        android:defaultValue="false"
+        android:key="@string/pref_log_to_file"
+        android:title="@string/pref_write_logfiles" />
+
 </PreferenceScreen>