Fix incorrect date format for some languages

app/src/main/java/org/isoron/uhabits/helpers/DateHelper.java

@@ -97,6 +97,22 @@ public class DateHelper
         return df.format(date);
     }
 
+    public static SimpleDateFormat getDateFormat(String skeleton)
+    {
+        String pattern;
+        Locale locale = Locale.getDefault();
+
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR2)
+            pattern = DateFormat.getBestDateTimePattern(locale, skeleton);
+        else
+            pattern = skeleton;
+
+        SimpleDateFormat format = new SimpleDateFormat(pattern, locale);
+        format.setTimeZone(TimeZone.getTimeZone("UTC"));
+
+        return format;
+    }
+
     public static SimpleDateFormat getCSVDateFormat()
     {
         SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.US);

app/src/main/java/org/isoron/uhabits/views/HabitFrequencyView.java

@@ -35,9 +35,7 @@ import java.util.Calendar;
 import java.util.Date;
 import java.util.GregorianCalendar;
 import java.util.HashMap;
-import java.util.Locale;
 import java.util.Random;
-import java.util.TimeZone;
 
 public class HabitFrequencyView extends ScrollableDataView implements HabitDataView
 {
@@ -93,11 +91,8 @@ public class HabitFrequencyView extends ScrollableDataView implements HabitDataV
 
         wdays = DateHelper.getShortDayNames();
 
-        dfMonth = new SimpleDateFormat("MMM", Locale.getDefault());
+        dfMonth = DateHelper.getDateFormat("MMM");
-        dfYear = new SimpleDateFormat("yyyy", Locale.getDefault());
+        dfYear = DateHelper.getDateFormat("yyyy");
-
-        dfMonth.setTimeZone(TimeZone.getTimeZone("GMT"));
-        dfYear.setTimeZone(TimeZone.getTimeZone("GMT"));
 
         rect = new RectF();
         prevRect = new RectF();

app/src/main/java/org/isoron/uhabits/views/HabitHistoryView.java

@@ -40,7 +40,6 @@ import org.isoron.uhabits.tasks.ToggleRepetitionTask;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.GregorianCalendar;
-import java.util.Locale;
 import java.util.Random;
 
 public class HabitHistoryView extends ScrollableDataView implements HabitDataView,
@@ -100,8 +99,8 @@ public class HabitHistoryView extends ScrollableDataView implements HabitDataVie
         checkmarks = new int[0];
         primaryColor = ColorHelper.palette[7];
         wdays = DateHelper.getShortDayNames();
-        dfMonth = new SimpleDateFormat("MMM", Locale.getDefault());
+        dfMonth = DateHelper.getDateFormat("MMM");
-        dfYear = new SimpleDateFormat("yyyy", Locale.getDefault());
+        dfYear = DateHelper.getDateFormat("yyyy");
 
         baseLocation = new RectF();
     }

app/src/main/java/org/isoron/uhabits/views/HabitScoreView.java

@@ -29,16 +29,15 @@ import android.graphics.RectF;
 import android.support.annotation.Nullable;
 import android.util.AttributeSet;
 
+import org.isoron.uhabits.R;
 import org.isoron.uhabits.helpers.ColorHelper;
 import org.isoron.uhabits.helpers.DateHelper;
-import org.isoron.uhabits.R;
 import org.isoron.uhabits.models.Habit;
 import org.isoron.uhabits.models.Score;
 
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.GregorianCalendar;
-import java.util.Locale;
 import java.util.Random;
 
 public class HabitScoreView extends ScrollableDataView implements HabitDataView
@@ -100,9 +99,9 @@ public class HabitScoreView extends ScrollableDataView implements HabitDataView
         createPaints();
         createColors();
 
-        dfYear = new SimpleDateFormat("yyyy", Locale.getDefault());
+        dfYear = DateHelper.getDateFormat("yyyy");
-        dfMonth = new SimpleDateFormat("MMM", Locale.getDefault());
+        dfMonth = DateHelper.getDateFormat("MMM");
-        dfDay = new SimpleDateFormat("d", Locale.getDefault());
+        dfDay = DateHelper.getDateFormat("d");
 
         rect = new RectF();
         prevRect = new RectF();