diff --git a/uhabits-core/src/main/java/org/isoron/uhabits/core/preferences/Preferences.java b/uhabits-core/src/main/java/org/isoron/uhabits/core/preferences/Preferences.java
index c1768c786..91914c227 100644
--- a/uhabits-core/src/main/java/org/isoron/uhabits/core/preferences/Preferences.java
+++ b/uhabits-core/src/main/java/org/isoron/uhabits/core/preferences/Preferences.java
@@ -21,6 +21,7 @@ package org.isoron.uhabits.core.preferences;
 
 import android.support.annotation.*;
 
+import org.apache.commons.lang3.*;
 import org.isoron.uhabits.core.models.*;
 import org.isoron.uhabits.core.ui.*;
 
@@ -364,5 +365,17 @@ public class Preferences
         void putString(String key, String value);
 
         void remove(String key);
+
+        default void putLongArray(String key, Long[] values) {
+            putString(key, StringUtils.join(values, ','));
+        }
+
+        default Long[] getLongArray(String key) {
+            String strNumbers = getString(key, "");
+            String parts[] = StringUtils.split(strNumbers, ',');
+            Long numbers[] = new Long[parts.length];
+            for (int i = 0; i < parts.length; i++) numbers[i] = Long.valueOf(parts[i]);
+            return numbers;
+        }
     }
 }
diff --git a/uhabits-core/src/test/java/org/isoron/uhabits/core/preferences/PropertiesStorageTest.java b/uhabits-core/src/test/java/org/isoron/uhabits/core/preferences/PropertiesStorageTest.java
index 7844da594..b1e2a7a57 100644
--- a/uhabits-core/src/test/java/org/isoron/uhabits/core/preferences/PropertiesStorageTest.java
+++ b/uhabits-core/src/test/java/org/isoron/uhabits/core/preferences/PropertiesStorageTest.java
@@ -23,7 +23,9 @@ import org.isoron.uhabits.core.*;
 import org.junit.*;
 
 import java.io.*;
+import java.util.*;
 
+import static junit.framework.TestCase.assertEquals;
 import static junit.framework.TestCase.assertFalse;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.IsEqual.equalTo;
@@ -88,4 +90,30 @@ public class PropertiesStorageTest extends BaseUnitTest
         assertThat(storage2.getLong("intKey", 200L), equalTo(64L));
         assertThat(storage2.getString("stringKey", ""), equalTo("Hello"));
     }
+
+    @Test
+    public void testLongArray() throws Exception
+    {
+        Long[] expected1 = new Long[]{1L, 2L, 3L, 5L};
+        Long[] expected2 = new Long[]{1L};
+        Long[] expected3 = new Long[]{};
+        Long[] expected4 = new Long[]{};
+
+        storage.putLongArray("key1", expected1);
+        storage.putLongArray("key2", expected2);
+        storage.putLongArray("key3", expected3);
+
+        Long[] actual1 = storage.getLongArray("key1");
+        Long[] actual2 = storage.getLongArray("key2");
+        Long[] actual3 = storage.getLongArray("key3");
+        Long[] actual4 = storage.getLongArray("invalidKey");
+
+        assertTrue(Arrays.equals(actual1, expected1));
+        assertTrue(Arrays.equals(actual2, expected2));
+        assertTrue(Arrays.equals(actual3, expected3));
+        assertTrue(Arrays.equals(actual4, expected4));
+
+        assertEquals("1,2,3,5", storage.getString("key1", ""));
+        assertEquals(1, storage.getLong("key2", -1));
+    }
 }