Switch between AM/PM when scrolling between forenoon and afternoon.

README.md

@@ -59,10 +59,9 @@ The goal is to make a cross platform variant of [DatePickerIOS](https://facebook
 - [x] Locale support. (AM/PM, 12h/24h toggled and strings translated) 
 - [x] Replace todays date with the string "Today" (considering locale)
 - [x] Animate to date when state change occur. 
+- [x] Switch between AM/PM when scrolling between forenoon and afternoon.
 - [ ] Transparent background support. (Probably need to include transparent gradient).
 - [ ] Align text to right.
 - [ ] Mode: date
 - [ ] Mode: time
-- [ ] Support maximumDate/minimumDate. (Gray out and animate back to max/min value if exceeded). 
-- [ ] Switch between AM/PM when scrolling between forenoon and afternoon.
-
+- [ ] Support maximumDate/minimumDate. (Gray out and animate back to max/min value if exceeded). 

android/src/main/java/com/henninghall/date_picker/PickerView.java

@@ -1,5 +1,6 @@
 package com.henninghall.date_picker;
 
+import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.RelativeLayout;
@@ -23,6 +24,8 @@ import cn.carbswang.android.numberpickerview.library.NumberPickerView;
 public class PickerView extends RelativeLayout {
 
     private final RelativeLayout wheelsWrapper;
+    private final NumberPickerView hourPicker;
+    private final NumberPickerView ampmPicker;
     private SimpleDateFormat dateFormat;
     private HourWheel hourWheel;
     private DayWheel dayWheel;
@@ -39,19 +42,20 @@ public class PickerView extends RelativeLayout {
 
         Locale locale = android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP ? Locale.forLanguageTag("en") : Locale.getDefault();
 
-        NumberPickerView hourPicker = (NumberPickerView) rootView.findViewById(R.id.hour);
-        hourWheel = new HourWheel(hourPicker, onWheelChangeListener, locale);
-
         NumberPickerView dayPicker = (NumberPickerView) rootView.findViewById(R.id.day);
         dayWheel = new DayWheel(dayPicker, onWheelChangeListener, locale);
 
         NumberPickerView minutePicker = (NumberPickerView) rootView.findViewById(R.id.minutes);
         minutesWheel = new MinutesWheel(minutePicker, onWheelChangeListener, locale);
 
-        NumberPickerView ampmPicker = (NumberPickerView) rootView.findViewById(R.id.ampm);
+        ampmPicker = (NumberPickerView) rootView.findViewById(R.id.ampm);
         ampmWheel = new AmPmWheel(ampmPicker, onWheelChangeListener, locale);
 
+        hourPicker = (NumberPickerView) rootView.findViewById(R.id.hour);
+        hourWheel = new HourWheel(hourPicker, onWheelChangeListener, locale);
+
         dateFormat = new SimpleDateFormat(getDateFormatTemplate(), Locale.US);
+        changeAmPmWhenPassingMidnightOrNoon();
     }
 
     WheelChangeListener onWheelChangeListener = new WheelChangeListener(){
@@ -59,9 +63,7 @@ public class PickerView extends RelativeLayout {
         public void onChange() {
             WritableMap event = Arguments.createMap();
             try {
-                String dateString = getDateString();
-
-                Date date = dateFormat.parse(dateString);
+                Date date = dateFormat.parse(getDateString());
                 event.putDouble("date", date.getTime());
             } catch (ParseException e) {
                 e.printStackTrace();
@@ -116,4 +118,19 @@ public class PickerView extends RelativeLayout {
         super.requestLayout();
         post(measureAndLayout);
     }
+
+    private void changeAmPmWhenPassingMidnightOrNoon(){
+        hourPicker.setOnValueChangeListenerInScrolling(new NumberPickerView.OnValueChangeListenerInScrolling() {
+            @Override
+            public void onValueChangeInScrolling(NumberPickerView picker, int oldVal, int newVal) {
+                if(Utils.usesAmPm(hourWheel.getLocale())){
+                    String oldValue = hourWheel.getValueAtIndex(oldVal);
+                    String newValue = hourWheel.getValueAtIndex(newVal);
+                    boolean passingNoonOrMidnight = (oldValue.equals("12") && newValue.equals("11")) || oldValue.equals("11") && newValue.equals("12");
+                    if (passingNoonOrMidnight) ampmPicker.smoothScrollToValue((ampmPicker.getValue() + 1) % 2);
+                }
+            }
+        });
+
+    }
 }

android/src/main/java/com/henninghall/date_picker/wheels/AmPmWheel.java

@@ -3,7 +3,11 @@ package com.henninghall.date_picker.wheels;
 import com.henninghall.date_picker.Utils;
 import com.henninghall.date_picker.WheelChangeListener;
 
+import java.text.Format;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.Date;
 import java.util.Locale;
 
 import cn.carbswang.android.numberpickerview.library.NumberPickerView;
@@ -19,6 +23,8 @@ public class AmPmWheel extends Wheel {
     void init() {
 
         Calendar cal = Calendar.getInstance();
+
+        cal.set(Calendar.HOUR_OF_DAY, 0);
         displayValues.add(displayFormat.format(cal.getTime()));
         values.add(format.format(cal.getTime()));
 

android/src/main/java/com/henninghall/date_picker/wheels/Wheel.java

@@ -46,7 +46,15 @@ public abstract class Wheel {
 
     public String getValue() {
         if(!visible()) return "";
-        return values.get(picker.getValue());
+        return getValueAtIndex(getIndex());
+    }
+
+    public int getIndex() {
+        return picker.getValue();
+    }
+
+    public String getValueAtIndex(int index) {
+        return values.get(index);
     }
 
     public void setValue(Date date) {
@@ -89,4 +97,7 @@ public abstract class Wheel {
         picker.setVisibility(View.VISIBLE);
     }
 
+    public Locale getLocale() {
+        return locale;
+    }
 }