Resolves #3389 show complete date on click

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

src/main/java/com/owncloud/android/db/PreferenceManager.java

@@ -47,6 +47,7 @@ public final class PreferenceManager {
     private static final String AUTO_PREF__UPLOAD_FILE_EXTENSION_URL = "prefs_upload_file_extension_url";
     private static final String AUTO_PREF__UPLOADER_BEHAVIOR = "prefs_uploader_behaviour";
     private static final String AUTO_PREF__GRID_COLUMNS = "grid_columns";
+    private static final String AUTO_PREF__SHOW_DETAILED_TIMESTAMP = "detailed_timestamp";
     public static final String AUTO_PREF__LAST_SEEN_VERSION_CODE = "lastSeenVersionCode";
     private static final String PREF__INSTANT_UPLOADING = "instant_uploading";
     private static final String PREF__INSTANT_VIDEO_UPLOADING = "instant_video_uploading";
@@ -541,6 +542,14 @@ public final class PreferenceManager {
         saveLongPreference(context, PREF__LOCK_TIMESTAMP, timestamp);
     }
 
+    public static boolean isShowDetailedTimestamp(Context context) {
+        return getDefaultSharedPreferences(context).getBoolean(AUTO_PREF__SHOW_DETAILED_TIMESTAMP, false);
+    }
+
+    public static void setShowDetailedTimestamp(Context context, boolean showDetailedTimestamp) {
+        saveBooleanPreference(context, AUTO_PREF__SHOW_DETAILED_TIMESTAMP, showDetailedTimestamp);
+    }
+
     private static void saveBooleanPreference(Context context, String key, boolean value) {
         SharedPreferences.Editor appPreferences = getDefaultSharedPreferences(context.getApplicationContext()).edit();
         appPreferences.putBoolean(key, value).apply();

src/main/java/com/owncloud/android/ui/fragment/FileDetailFragment.java

@@ -4,7 +4,7 @@
  *   @author Bartek Przybylski
  *   @author David A. Velasco
  *   @author Andy Scherzinger
- *   Copyright (C) 2011  Bartek Przybylski
+ *   Copyright (C) 2011 Bartek Przybylski
  *   Copyright (C) 2016 ownCloud Inc.
  *   Copyright (C) 2018 Andy Scherzinger
  *
@@ -44,6 +44,7 @@ import com.owncloud.android.R;
 import com.owncloud.android.datamodel.FileDataStorageManager;
 import com.owncloud.android.datamodel.OCFile;
 import com.owncloud.android.datamodel.ThumbnailsCacheManager;
+import com.owncloud.android.db.PreferenceManager;
 import com.owncloud.android.files.FileMenuFilter;
 import com.owncloud.android.files.services.FileDownloader.FileDownloaderBinder;
 import com.owncloud.android.files.services.FileUploader.FileUploaderBinder;
@@ -249,6 +250,7 @@ public class FileDetailFragment extends FileFragment implements OnClickListener
             cancelButton.setOnClickListener(this);
             favoriteIcon.setOnClickListener(this);
             overflowMenu.setOnClickListener(this);
+            fileModifiedTimestamp.setOnClickListener(this);
 
             updateFileDetails(false, false);
         }
@@ -452,6 +454,11 @@ public class FileDetailFragment extends FileFragment implements OnClickListener
                 onOverflowIconClicked(v);
                 break;
             }
+            case R.id.modified: {
+                boolean flag = !PreferenceManager.isShowDetailedTimestamp(getContext());
+                PreferenceManager.setShowDetailedTimestamp(getContext(), flag);
+                setFileModificationTimestamp(getFile(), flag);
+            }
             default:
                 Log_OC.e(TAG, "Incorrect view clicked!");
                 break;
@@ -508,7 +515,10 @@ public class FileDetailFragment extends FileFragment implements OnClickListener
                 fileName.setVisibility(View.GONE);
             }
             fileSize.setText(DisplayUtils.bytesToHumanReadable(file.getFileLength()));
-            fileModifiedTimestamp.setText(DisplayUtils.getRelativeTimestamp(getContext(), file.getModificationTimestamp()));
+
+            boolean showDetailedTimestamp = PreferenceManager.isShowDetailedTimestamp(getContext());
+            setFileModificationTimestamp(file, showDetailedTimestamp);
+
             setFilePreview(file);
             setFavoriteIconStatus(file.isFavorite());
 
@@ -536,6 +546,14 @@ public class FileDetailFragment extends FileFragment implements OnClickListener
         getView().invalidate();
     }
 
+    private void setFileModificationTimestamp(OCFile file, boolean showDetailedTimestamp) {
+        if (showDetailedTimestamp) {
+            fileModifiedTimestamp.setText(DisplayUtils.unixTimeToHumanReadable(file.getModificationTimestamp()));
+        } else {
+            fileModifiedTimestamp.setText(DisplayUtils.getRelativeTimestamp(getContext(), file.getModificationTimestamp()));
+        }
+    }
+
     private void setFavoriteIconStatus(boolean isFavorite) {
         if (isFavorite) {
             favoriteIcon.setImageDrawable(getResources().getDrawable(R.drawable.ic_star));