Allow user to change first day of the week

Closes #421
2025-12-07 09:38:52 -06:00 · 2019-12-31 13:40:56 -06:00
parent 5cdb9eb9d5
commit 7801c933f0
31 changed files with 283 additions and 108 deletions
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/dialogs/HistoryEditorDialog.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/dialogs/HistoryEditorDialog.java
@@ -30,6 +30,7 @@ import android.util.*;
 import org.isoron.uhabits.*;
 import org.isoron.uhabits.activities.common.views.*;
 import org.isoron.uhabits.core.models.*;
+import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.tasks.*;
 import org.isoron.uhabits.utils.*;

@@ -51,6 +52,8 @@ public class HistoryEditorDialog extends AppCompatDialogFragment

    private TaskRunner taskRunner;

+    private Preferences prefs;
+
    public HistoryEditorDialog()
    {
        this.controller = new Controller() {};
@@ -72,9 +75,11 @@ public class HistoryEditorDialog extends AppCompatDialogFragment
            (HabitsApplication) getActivity().getApplicationContext();
        habitList = app.getComponent().getHabitList();
        taskRunner = app.getComponent().getTaskRunner();
+        prefs = app.getComponent().getPreferences();

        historyChart = new HistoryChart(context);
        historyChart.setController(controller);
+        historyChart.setFirstWeekday(prefs.getFirstWeekday());

        if (savedInstanceState != null)
        {
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/dialogs/WeekdayPickerDialog.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/dialogs/WeekdayPickerDialog.java
@@ -29,6 +29,8 @@ import org.isoron.uhabits.*;
 import org.isoron.uhabits.core.models.*;
 import org.isoron.uhabits.core.utils.*;

+import java.util.*;
+
 /**
 * Dialog that allows the user to pick one or more days of the week.
 */
@@ -59,8 +61,9 @@ public class WeekdayPickerDialog extends AppCompatDialogFragment implements
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder
            .setTitle(R.string.select_weekdays)
-            .setMultiChoiceItems(DateUtils.getLongDayNames(), selectedDays,
-                this)
+            .setMultiChoiceItems(DateUtils.getLongWeekdayNames(Calendar.SATURDAY),
+                    selectedDays,
+                    this)
            .setPositiveButton(android.R.string.yes, this)
            .setNegativeButton(android.R.string.cancel, (dialog, which) -> {
                dismiss();
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java
@@ -69,8 +69,11 @@ public class FrequencyChart extends ScrollableChart

    @NonNull
    private HashMap<Timestamp, Integer[]> frequency;
+
    private int maxFreq;

+    private int firstWeekday = Calendar.SUNDAY;
+
    public FrequencyChart(Context context)
    {
        super(context);
@@ -98,6 +101,12 @@ public class FrequencyChart extends ScrollableChart
        postInvalidate();
    }

+    public void setFirstWeekday(int firstWeekday)
+    {
+        this.firstWeekday = firstWeekday;
+        postInvalidate();
+    }
+
    private int getMaxFreq(HashMap<Timestamp, Integer[]> frequency)
    {
        int maxValue = 1;
@@ -144,7 +153,6 @@ public class FrequencyChart extends ScrollableChart
        prevRect.setEmpty();

        GregorianCalendar currentDate = DateUtils.getStartOfTodayCalendar();
-
        currentDate.set(Calendar.DAY_OF_MONTH, 1);
        currentDate.add(Calendar.MONTH, -nColumns + 2 - getDataOffset());

@@ -193,11 +201,11 @@ public class FrequencyChart extends ScrollableChart

    private void drawColumn(Canvas canvas, RectF rect, GregorianCalendar date)
    {
-        Integer values[] = frequency.get(new Timestamp(date));
+        Integer[] values = frequency.get(new Timestamp(date));
        float rowHeight = rect.height() / 8.0f;
        prevRect.set(rect);

-        Integer[] localeWeekdayList = DateUtils.getLocaleWeekdayList();
+        int[] localeWeekdayList = DateUtils.getWeekdaySequence(firstWeekday);
        for (int j = 0; j < localeWeekdayList.length; j++)
        {
            rect.set(0, 0, baseSize, baseSize);
@@ -233,7 +241,7 @@ public class FrequencyChart extends ScrollableChart
        pText.setColor(textColor);
        pGrid.setColor(gridColor);

-        for (String day : DateUtils.getLocaleDayNames(Calendar.SHORT))
+        for (String day : DateUtils.getShortWeekdayNames(firstWeekday))
        {
            canvas.drawText(day, rGrid.right - columnWidth,
                rGrid.top + rowHeight / 2 + 0.25f * em, pText);
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/HistoryChart.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/HistoryChart.java
@@ -93,6 +93,8 @@ public class HistoryChart extends ScrollableChart

    private boolean isNumerical = false;

+    private int firstWeekday = Calendar.SUNDAY;
+
    @NonNull
    private Controller controller;

@@ -210,6 +212,12 @@ public class HistoryChart extends ScrollableChart
        postInvalidate();
    }

+    public void setFirstWeekday(int firstWeekday)
+    {
+        this.firstWeekday = firstWeekday;
+        postInvalidate();
+    }
+
    protected void initPaints()
    {
        pTextHeader = new Paint();
@@ -293,7 +301,7 @@ public class HistoryChart extends ScrollableChart
    {
        float verticalOffset = pTextHeader.getFontSpacing() * 0.4f;

-        for (String day : DateUtils.getLocaleDayNames(Calendar.SHORT))
+        for (String day : DateUtils.getShortWeekdayNames(firstWeekday))
        {
            location.offset(0, columnWidth);
            canvas.drawText(day, location.left + headerTextOffset,
@@ -375,7 +383,7 @@ public class HistoryChart extends ScrollableChart
    {
        float width = 0;

-        for (String w : DateUtils.getLocaleDayNames(Calendar.SHORT))
+        for (String w : DateUtils.getShortWeekdayNames(firstWeekday))
            width = Math.max(width, pSquareFg.measureText(w));

        return width;
@@ -473,7 +481,7 @@ public class HistoryChart extends ScrollableChart
        int realWeekday =
            DateUtils.getStartOfTodayCalendar().get(Calendar.DAY_OF_WEEK);
        todayPositionInColumn =
-            (7 + realWeekday - baseDate.getFirstDayOfWeek()) % 7;
+            (7 + realWeekday - firstWeekday) % 7;

        baseDate.add(Calendar.DAY_OF_YEAR, -nDays);
        baseDate.add(Calendar.DAY_OF_YEAR, -todayPositionInColumn);
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/BarCard.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/BarCard.java
@@ -28,6 +28,7 @@ import org.isoron.uhabits.*;
 import org.isoron.uhabits.R;
 import org.isoron.uhabits.activities.common.views.*;
 import org.isoron.uhabits.core.models.*;
+import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.tasks.*;
 import org.isoron.uhabits.utils.*;

@@ -56,6 +57,9 @@ public class BarCard extends HabitCard

    private int bucketSize;

+    @Nullable
+    private Preferences prefs;
+
    public BarCard(Context context)
    {
        super(context);
@@ -84,6 +88,12 @@ public class BarCard extends HabitCard

    private void init()
    {
+        Context appContext = getContext().getApplicationContext();
+        if (appContext instanceof HabitsApplication)
+        {
+            HabitsApplication app = (HabitsApplication) appContext;
+            prefs = app.getComponent().getPreferences();
+        }
        inflate(getContext(), R.layout.show_habit_bar, this);
        ButterKnife.bind(this);
        boolSpinner.setSelection(1);
@@ -120,8 +130,11 @@ public class BarCard extends HabitCard
        {
            if (isCanceled()) return;
            List<Checkmark> checkmarks;
+            int firstWeekday = Calendar.SATURDAY;
+            if (prefs != null) firstWeekday = prefs.getFirstWeekday();
            if (bucketSize == 1) checkmarks = habit.getCheckmarks().getAll();
-            else checkmarks = habit.getCheckmarks().groupBy(getTruncateField(bucketSize));
+            else checkmarks = habit.getCheckmarks().groupBy(getTruncateField(bucketSize),
+                                                            firstWeekday);
            chart.setCheckmarks(checkmarks);
            chart.setBucketSize(bucketSize);
        }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/FrequencyCard.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/FrequencyCard.java
@@ -28,6 +28,7 @@ import org.isoron.uhabits.*;
 import org.isoron.uhabits.R;
 import org.isoron.uhabits.activities.common.views.*;
 import org.isoron.uhabits.core.models.*;
+import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.tasks.*;
 import org.isoron.uhabits.utils.*;

@@ -43,6 +44,9 @@ public class FrequencyCard extends HabitCard
    @BindView(R.id.frequencyChart)
    FrequencyChart chart;

+    @Nullable
+    private Preferences prefs;
+
    public FrequencyCard(Context context)
    {
        super(context);
@@ -63,6 +67,12 @@ public class FrequencyCard extends HabitCard

    private void init()
    {
+        Context appContext = getContext().getApplicationContext();
+        if (appContext instanceof HabitsApplication)
+        {
+            HabitsApplication app = (HabitsApplication) appContext;
+            prefs = app.getComponent().getPreferences();
+        }
        inflate(getContext(), R.layout.show_habit_frequency, this);
        ButterKnife.bind(this);
        if (isInEditMode()) initEditMode();
@@ -84,6 +94,7 @@ public class FrequencyCard extends HabitCard
            if (isCanceled()) return;
            RepetitionList reps = getHabit().getRepetitions();
            HashMap<Timestamp, Integer[]> frequency = reps.getWeekdayFrequency();
+            if(prefs != null) chart.setFirstWeekday(prefs.getFirstWeekday());
            chart.setFrequency(frequency);
        }

--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/HistoryCard.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/HistoryCard.java
@@ -28,6 +28,7 @@ import org.isoron.uhabits.*;
 import org.isoron.uhabits.R;
 import org.isoron.uhabits.activities.common.views.*;
 import org.isoron.uhabits.core.models.*;
+import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.tasks.*;
 import org.isoron.uhabits.utils.*;

@@ -41,9 +42,12 @@ public class HistoryCard extends HabitCard
    @BindView(R.id.title)
    TextView title;

-    @NonNull
+    @Nullable
    private Controller controller;

+    @Nullable
+    private Preferences prefs;
+
    public HistoryCard(Context context)
    {
        super(context);
@@ -59,16 +63,23 @@ public class HistoryCard extends HabitCard
    @OnClick(R.id.edit)
    public void onClickEditButton()
    {
-        controller.onEditHistoryButtonClick();
+        if(controller != null) controller.onEditHistoryButtonClick();
    }

-    public void setController(@NonNull Controller controller)
+    public void setController(@Nullable Controller controller)
    {
        this.controller = controller;
    }

    private void init()
    {
+        Context appContext = getContext().getApplicationContext();
+        if (appContext instanceof HabitsApplication)
+        {
+            HabitsApplication app = (HabitsApplication) appContext;
+            prefs = app.getComponent().getPreferences();
+        }
+
        inflate(getContext(), R.layout.show_habit_history, this);
        ButterKnife.bind(this);
        controller = new Controller() {};
@@ -107,7 +118,8 @@ public class HistoryCard extends HabitCard
        public void doInBackground()
        {
            if (isCanceled()) return;
-            int checkmarks[] = habit.getCheckmarks().getAllValues();
+            int[] checkmarks = habit.getCheckmarks().getAllValues();
+            if(prefs != null) chart.setFirstWeekday(prefs.getFirstWeekday());
            chart.setCheckmarks(checkmarks);
        }

--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/ScoreCard.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/show/views/ScoreCard.java
@@ -143,9 +143,12 @@ public class ScoreCard extends HabitCard
            if (isCanceled()) return;
            List<Score> scores;
            ScoreList scoreList = getHabit().getScores();
+            int firstWeekday = Calendar.SATURDAY;
+            if (prefs != null) firstWeekday = prefs.getFirstWeekday();
+            Log.d("ScoreCard", "firstWeekday="+firstWeekday);

            if (bucketSize == 1) scores = scoreList.toList();
-            else scores = scoreList.groupBy(getTruncateField(bucketSize));
+            else scores = scoreList.groupBy(getTruncateField(bucketSize), firstWeekday);

            chart.setScores(scores);
            chart.setBucketSize(bucketSize);
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.java
@@ -32,9 +32,12 @@ import org.isoron.uhabits.R;
 import org.isoron.uhabits.*;
 import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.ui.*;
+import org.isoron.uhabits.core.utils.*;
 import org.isoron.uhabits.notifications.*;
 import org.isoron.uhabits.widgets.*;

+import java.util.*;
+
 import static android.media.RingtoneManager.*;
 import static android.os.Build.VERSION.*;
 import static org.isoron.uhabits.activities.habits.list.ListHabitsScreenKt.*;
@@ -143,6 +146,8 @@ public class SettingsFragment extends PreferenceFragmentCompat
            devCategory.setVisible(false);
        }

+        updateWeekdayPreference();
+
        if (SDK_INT < Build.VERSION_CODES.O)
            findPreference("reminderCustomize").setVisible(false);
        else
@@ -154,6 +159,19 @@ public class SettingsFragment extends PreferenceFragmentCompat
        updateSync();
    }

+    private void updateWeekdayPreference()
+    {
+        if (prefs == null) return;
+        ListPreference weekdayPref = (ListPreference) findPreference("pref_first_weekday");
+        int currentFirstWeekday = prefs.getFirstWeekday();
+        String[] dayNames = DateUtils.getLongWeekdayNames(Calendar.SATURDAY);
+        String[] dayValues = {"7", "1", "2", "3", "4", "5", "6"};
+        weekdayPref.setEntries(dayNames);
+        weekdayPref.setEntryValues(dayValues);
+        weekdayPref.setDefaultValue(Integer.toString(currentFirstWeekday));
+        weekdayPref.setSummary(dayNames[currentFirstWeekday % 7]);
+    }
+
    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
                                          String key)
@@ -163,6 +181,7 @@ public class SettingsFragment extends PreferenceFragmentCompat
            Log.d("SettingsFragment", "updating widgets");
            widgetUpdater.updateWidgets();
        }
+        if (key.equals("pref_first_weekday")) updateWeekdayPreference();
        BackupManager.dataChanged("org.isoron.uhabits");
        updateSync();
    }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/utils/AndroidDateUtils.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/utils/AndroidDateUtils.java
@@ -41,8 +41,8 @@ public class AndroidDateUtils

    public static String formatWeekdayList(Context context, boolean weekday[])
    {
-        String shortDayNames[] = org.isoron.uhabits.core.utils.DateUtils.getShortDayNames();
-        String longDayNames[] = org.isoron.uhabits.core.utils.DateUtils.getLongDayNames();
+        String shortDayNames[] = org.isoron.uhabits.core.utils.DateUtils.getShortWeekdayNames(Calendar.SATURDAY);
+        String longDayNames[] = org.isoron.uhabits.core.utils.DateUtils.getLongWeekdayNames(Calendar.SATURDAY);
        StringBuilder buffer = new StringBuilder();

        int count = 0;
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/BaseWidgetProvider.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/BaseWidgetProvider.java
@@ -40,6 +40,7 @@ public abstract class BaseWidgetProvider extends AppWidgetProvider
    private HabitList habits;

    private Preferences preferences;
+
    private WidgetPreferences widgetPrefs;

    public static void updateAppWidget(@NonNull AppWidgetManager manager,
@@ -195,4 +196,9 @@ public abstract class BaseWidgetProvider extends AppWidgetProvider
        preferences = app.getComponent().getPreferences();
        widgetPrefs = app.getComponent().getWidgetPreferences();
    }
+
+    public Preferences getPreferences()
+    {
+        return preferences;
+    }
 }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/FrequencyWidget.kt
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/FrequencyWidget.kt
@@ -29,7 +29,8 @@ import org.isoron.uhabits.widgets.views.*
 class FrequencyWidget(
        context: Context,
        widgetId: Int,
-        private val habit: Habit
+        private val habit: Habit,
+        private val firstWeekday: Int
 ) : BaseWidget(context, widgetId) {

    override fun getOnClickPendingIntent(context: Context) =
@@ -40,6 +41,7 @@ class FrequencyWidget(
        widgetView.setTitle(habit.name)
        widgetView.setBackgroundAlpha(preferedBackgroundAlpha)
        (widgetView.dataView as FrequencyChart).apply {
+            setFirstWeekday(firstWeekday)
            setColor(PaletteUtils.getColor(context, habit.color))
            setFrequency(habit.repetitions.weekdayFrequency)
        }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/FrequencyWidgetProvider.kt
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/FrequencyWidgetProvider.kt
@@ -24,7 +24,10 @@ import android.content.*
 class FrequencyWidgetProvider : BaseWidgetProvider() {
    override fun getWidgetFromId(context: Context, id: Int): BaseWidget {
        val habits = getHabitsFromWidgetId(id)
-        if (habits.size == 1) return FrequencyWidget(context, id, habits[0])
+        if (habits.size == 1) return FrequencyWidget(context,
+                                                     id,
+                                                     habits[0],
+                                                     preferences.firstWeekday)
        else return StackWidget(context, id, StackWidgetType.FREQUENCY, habits)
    }
 }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/HistoryWidget.kt
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/HistoryWidget.kt
@@ -30,7 +30,8 @@ import org.isoron.uhabits.widgets.views.*
 class HistoryWidget(
        context: Context,
        id: Int,
-        private val habit: Habit
+        private val habit: Habit,
+        private val firstWeekday: Int
 ) : BaseWidget(context, id) {

    override fun getOnClickPendingIntent(context: Context): PendingIntent {
@@ -41,6 +42,7 @@ class HistoryWidget(
        val widgetView = view as GraphWidgetView
        widgetView.setBackgroundAlpha(preferedBackgroundAlpha)
        (widgetView.dataView as HistoryChart).apply {
+            setFirstWeekday(firstWeekday)
            setColor(PaletteUtils.getColor(context, habit.color))
            setCheckmarks(habit.checkmarks.allValues)
        }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/HistoryWidgetProvider.kt
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/HistoryWidgetProvider.kt
@@ -23,7 +23,10 @@ import android.content.*
 class HistoryWidgetProvider : BaseWidgetProvider() {
    override fun getWidgetFromId(context: Context, id: Int): BaseWidget {
        val habits = getHabitsFromWidgetId(id)
-        if (habits.size == 1) return HistoryWidget(context, id, habits[0])
+        if (habits.size == 1) return HistoryWidget(context,
+                                                   id,
+                                                   habits[0],
+                                                   preferences.firstWeekday)
        else return StackWidget(context, id, StackWidgetType.HISTORY, habits)
    }
 }
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/ScoreWidget.kt
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/ScoreWidget.kt
@@ -40,7 +40,8 @@ class ScoreWidget(
        val size = ScoreCard.BUCKET_SIZES[prefs.defaultScoreSpinnerPosition]
        val scores = when(size) {
            1 -> habit.scores.toList()
-            else -> habit.scores.groupBy(ScoreCard.getTruncateField(size))
+            else -> habit.scores.groupBy(ScoreCard.getTruncateField(size),
+                                         prefs.firstWeekday)
        }

        val widgetView = view as GraphWidgetView
--- a/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/StackWidgetService.java
+++ b/android/uhabits-android/src/main/java/org/isoron/uhabits/widgets/StackWidgetService.java
@@ -9,6 +9,7 @@ import android.widget.*;

 import org.isoron.uhabits.*;
 import org.isoron.uhabits.core.models.*;
+import org.isoron.uhabits.core.preferences.*;
 import org.isoron.uhabits.core.utils.*;

 import java.util.*;
@@ -87,18 +88,19 @@ class StackRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory
    }

    @NonNull
-    private BaseWidget constructWidget(@NonNull Habit habit)
+    private BaseWidget constructWidget(@NonNull Habit habit,
+                                       @NonNull Preferences prefs)
    {
        switch (widgetType)
        {
            case CHECKMARK:
                return new CheckmarkWidget(context, widgetId, habit);
            case FREQUENCY:
-                return new FrequencyWidget(context, widgetId, habit);
+                return new FrequencyWidget(context, widgetId, habit, prefs.getFirstWeekday());
            case SCORE:
                return new ScoreWidget(context, widgetId, habit);
            case HISTORY:
-                return new HistoryWidget(context, widgetId, habit);
+                return new HistoryWidget(context, widgetId, habit, prefs.getFirstWeekday());
            case STREAKS:
                return new StreakWidget(context, widgetId, habit);
        }
@@ -136,6 +138,7 @@ class StackRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory
        Log.i("StackRemoteViewsFactory", "onDataSetChanged started");

        HabitsApplication app = (HabitsApplication) context.getApplicationContext();
+        Preferences prefs = app.getComponent().getPreferences();
        HabitList habitList = app.getComponent().getHabitList();
        Bundle options = AppWidgetManager.getInstance(context).getAppWidgetOptions(widgetId);
        ArrayList<RemoteViews> newRemoteViews = new ArrayList<>();
@@ -147,7 +150,7 @@ class StackRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory
            Habit h = habitList.getById(id);
            if (h == null) throw new HabitNotFoundException();

-            BaseWidget widget = constructWidget(h);
+            BaseWidget widget = constructWidget(h, prefs);
            widget.setDimensions(getDimensionsFromOptions(context, options));

            RemoteViews landscapeViews = widget.getLandscapeRemoteViews();
--- a/android/uhabits-android/src/main/res/values/strings.xml
+++ b/android/uhabits-android/src/main/res/values/strings.xml
@@ -242,5 +242,6 @@
    <string name="database">Database</string>
    <string name="widget_opacity_title">Widget opacity</string>
    <string name="widget_opacity_description">Makes widgets more transparent or more opaque in your home screen.</string>
+    <string name="first_day_of_the_week">First day of the week</string>

 </resources>
--- a/android/uhabits-android/src/main/res/xml/preferences.xml
+++ b/android/uhabits-android/src/main/res/xml/preferences.xml
@@ -55,6 +55,11 @@
                android:title="@string/widget_opacity_title"
                app:iconSpaceReserved="false" />

+        <ListPreference
+                android:key="pref_first_weekday"
+                android:title="@string/first_day_of_the_week"
+                app:iconSpaceReserved="false" />
+
    </PreferenceCategory>

    <PreferenceCategory