Rerender of android picker no longer clears users selection

android/src/main/java/com/reactcommunity/rndatetimepicker/RNDate.java

@@ -1,26 +1,58 @@
 package com.reactcommunity.rndatetimepicker;
 
 import java.util.Calendar;
+
 import android.os.Bundle;
 
 public class RNDate {
-  private Calendar now;
+    private Calendar now;
 
-  public RNDate(Bundle args) {
-    now = Calendar.getInstance();
+    public RNDate(Bundle args) {
+        now = Calendar.getInstance();
 
-    if (args != null && args.containsKey(RNConstants.ARG_VALUE)) {
-      set(args.getLong(RNConstants.ARG_VALUE));
+        if (args != null && args.containsKey(RNConstants.ARG_VALUE)) {
+            set(args.getLong(RNConstants.ARG_VALUE));
+        }
     }
-  }
 
-  public void set(long value) {
-    now.setTimeInMillis(value);
-  }
+    public Calendar get() {
+        return now;
+    }
 
-  public int year() { return now.get(Calendar.YEAR); }
-  public int month() { return now.get(Calendar.MONTH); }
-  public int day() { return now.get(Calendar.DAY_OF_MONTH); }
-  public int hour() { return now.get(Calendar.HOUR_OF_DAY); }
-  public int minute() { return now.get(Calendar.MINUTE); }
+    public void set(long value) {
+        now.setTimeInMillis(value);
+    }
+
+    public int year() {
+        return now.get(Calendar.YEAR);
+    }
+
+    public int month() {
+        return now.get(Calendar.MONTH);
+    }
+
+    public int day() {
+        return now.get(Calendar.DAY_OF_MONTH);
+    }
+
+    public int hour() {
+        return now.get(Calendar.HOUR_OF_DAY);
+    }
+
+    public int minute() {
+        return now.get(Calendar.MINUTE);
+    }
+
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+
+        if (!(o instanceof RNDate)) {
+            return false;
+        }
+        RNDate otherDate = (RNDate) o;
+
+        return now.equals(otherDate.get());
+    }
 }

android/src/main/java/com/reactcommunity/rndatetimepicker/RNDatePickerDialogFragment.java

@@ -30,6 +30,9 @@
 public class RNDatePickerDialogFragment extends DialogFragment {
   private DatePickerDialog instance;
 
+  @Nullable
+  private RNDate date;
+
   @Nullable
   private OnDateSetListener mOnDateSetListener;
   @Nullable
@@ -40,12 +43,24 @@ public class RNDatePickerDialogFragment extends DialogFragment {
   @Override
   public Dialog onCreateDialog(Bundle savedInstanceState) {
     Bundle args = getArguments();
+    date = new RNDate(args);
     instance = createDialog(args, getActivity(), mOnDateSetListener);
     return instance;
   }
 
   public void update(Bundle args) {
-    final RNDate date = new RNDate(args);
+    final RNDate newDate = new RNDate(args);
+
+    // React may rerender components whenever it feels like, even when props haven't changed.
+    // Calling update on the native android picker will always change its currently selected value.
+    // This happens even if the user has changed the selection in the picker.
+    // By only updating the selected value of the picker if it actually differs from last render,
+    // we avoid the user suddenly having their selection change seemingly randomly.
+    if (date != null && date.equals(newDate)) {
+      return;
+    }
+
+    date = newDate;
     instance.updateDate(date.year(), date.month(), date.day());
   }
 

android/src/main/java/com/reactcommunity/rndatetimepicker/RNTimePickerDialogFragment.java

@@ -28,6 +28,9 @@
 public class RNTimePickerDialogFragment extends DialogFragment {
   private TimePickerDialog instance;
 
+  @Nullable
+  private RNDate date;
+
   @Nullable
   private OnTimeSetListener mOnTimeSetListener;
   @Nullable
@@ -38,12 +41,24 @@ public class RNTimePickerDialogFragment extends DialogFragment {
   @Override
   public Dialog onCreateDialog(Bundle savedInstanceState) {
     final Bundle args = getArguments();
+    date = new RNDate(args);
     instance = createDialog(args, getActivity(), mOnTimeSetListener);
     return instance;
   }
 
   public void update(Bundle args) {
-    final RNDate date = new RNDate(args);
+    final RNDate newDate = new RNDate(args);
+
+    // React may rerender components whenever it feels like, even when props haven't changed.
+    // Calling update on the native android picker will always change its currently selected value.
+    // This happens even if the user has changed the selection in the picker.
+    // By only updating the selected value of the picker if it actually differs from last render,
+    // we avoid the user suddenly having their selection change seemingly randomly.
+    if (date != null && date.equals(newDate)) {
+      return;
+    }
+
+    date = newDate;
     instance.updateTime(date.hour(), date.minute());
   }