Add preference to enable saving debug log to file

android_app/app/src/main/java/com/health/openscale/gui/preferences/AboutPreferences.java

@@ -15,14 +15,79 @@
 */
 package com.health.openscale.gui.preferences;
 
+import android.content.Intent;
+import android.net.Uri;
 import android.os.Bundle;
+import android.preference.Preference;
 import android.preference.PreferenceFragment;
+import android.util.Log;
 
 import com.health.openscale.BuildConfig;
 import com.health.openscale.R;
 
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+import timber.log.Timber;
+
+import static android.app.Activity.RESULT_OK;
+
 public class AboutPreferences extends PreferenceFragment {
     private static final String KEY_APP_VERSION = "pref_app_version";
+    private static final String KEY_DEBUG_LOG = "debug_log";
+
+    private static final int DEBUG_LOG_REQUEST = 100;
+
+    class FileDebugTree extends Timber.DebugTree {
+        PrintWriter writer;
+        DateFormat format;
+
+        FileDebugTree(OutputStream output) {
+            writer = new PrintWriter(output, true);
+            format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
+        }
+
+        void close() {
+            writer.close();
+        }
+
+        private String priorityToString(int priority) {
+            switch (priority) {
+                case Log.ASSERT:
+                    return "Assert";
+                case Log.ERROR:
+                    return "Error";
+                case Log.WARN:
+                    return "Warning";
+                case Log.INFO:
+                    return "Info";
+                case Log.DEBUG:
+                    return "Debug";
+                case Log.VERBOSE:
+                    return "Verbose";
+            }
+            return String.format("Unknown (%d)", priority);
+        }
+
+        @Override
+        protected void log(int priority, String tag, String message, Throwable t) {
+            writer.printf("%s %s %s: %s\n",
+                    format.format(new Date()), priorityToString(priority), tag, message);
+        }
+    }
+
+    private FileDebugTree getEnabledFileDebugTree() {
+        for (Timber.Tree tree : Timber.forest()) {
+            if (tree instanceof FileDebugTree) {
+                return (FileDebugTree) tree;
+            }
+        }
+        return null;
+    }
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -30,6 +95,59 @@ public class AboutPreferences extends PreferenceFragment {
 
         addPreferencesFromResource(R.xml.about_preferences);
 
-        findPreference(KEY_APP_VERSION).setSummary("v" + BuildConfig.VERSION_NAME + " (" + BuildConfig.VERSION_CODE + ")");
+        findPreference(KEY_APP_VERSION).setSummary(
+                String.format("v%s (%d)", BuildConfig.VERSION_NAME, BuildConfig.VERSION_CODE));
+
+        Preference debugLog = findPreference(KEY_DEBUG_LOG);
+        debugLog.setSummary(getEnabledFileDebugTree() != null
+                ? R.string.info_is_enable : R.string.info_is_not_enable);
+        debugLog.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+            @Override
+            public boolean onPreferenceClick(Preference preference) {
+                FileDebugTree tree = getEnabledFileDebugTree();
+                if (tree != null) {
+                    Timber.d("Debug log disabled");
+                    tree.close();
+                    Timber.uproot(tree);
+                    preference.setSummary(R.string.info_is_not_enable);
+                    return true;
+                }
+
+                DateFormat format = new SimpleDateFormat("yyyy-MM-dd_HH-mm");
+                String fileName = String.format("openScale_%s.txt", format.format(new Date()));
+
+                Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+                intent.addCategory(Intent.CATEGORY_OPENABLE);
+                intent.setType("text/plain");
+                intent.putExtra(Intent.EXTRA_TITLE, fileName);
+
+                startActivityForResult(intent, DEBUG_LOG_REQUEST);
+
+                return true;
+            }
+        });
+    }
+
+    private void startLogTo(Uri uri) {
+        try {
+            OutputStream output = getActivity().getContentResolver().openOutputStream(uri);
+            Timber.plant(new FileDebugTree(output));
+            findPreference(KEY_DEBUG_LOG).setSummary(R.string.info_is_enable);
+            Timber.d("Debug log enabled (%s v%s (%d))",
+                    getResources().getString(R.string.app_name),
+                    BuildConfig.VERSION_NAME, BuildConfig.VERSION_CODE);
+        }
+        catch (IOException ex) {
+            Timber.e(ex, "Failed to open debug log %s", uri.toString());
+        }
+    }
+
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        if (requestCode == DEBUG_LOG_REQUEST && resultCode == RESULT_OK && data != null) {
+            startLogTo(data.getData());
+        }
     }
 }

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

@@ -217,4 +217,6 @@
     <string name="label_monthly">monthly</string>
     <string name="label_scale_not_supported">Is your scale not supported?</string>
     <string name="label_click_to_help_add_support">Click here to help add support for it</string>
+    <string name="label_development">Development</string>
+    <string name="label_debug_log">Save debug log to file</string>
 </resources>

android_app/app/src/main/res/xml/about_preferences.xml

@@ -22,4 +22,10 @@
         android:selectable="false"
         android:title="@string/label_license"
         android:summary="GPLv3"/>
+    <PreferenceCategory android:title="@string/label_development">
+        <Preference
+            android:key="debug_log"
+            android:persistent="false"
+            android:title="@string/label_debug_log" />
+    </PreferenceCategory>
 </PreferenceScreen>