Fixed and added unit for MaterialDatePicker Exception on modal Dialog dateField.clear() #707

Author: kevzlou7979

gwt-material/src/main/java/gwt/material/design/client/ui/MaterialDatePicker.java

@@ -655,12 +655,14 @@ public void stop() {
     @Override
     public void clear() {
         dateInput.clear();
-        getPicker().set("select", null);
-
+        if (getPicker() != null) {
+            getPicker().set("select", null);
+        }
         // Clear all active / error styles on datepicker
         clearErrorOrSuccess();
         label.removeStyleName(CssName.ACTIVE);
         dateInput.removeStyleName(CssName.VALID);
+
     }
 
     protected void setPopupEnabled(boolean enabled) {

gwt-material/src/test/java/gwt/material/design/client/ui/MaterialDatePickerTest.java

@@ -162,15 +162,26 @@ public void testAutoClose() {
     }
 
     public void testClear() {
+        // UiBinder
         // given
-        MaterialDatePicker picker = getWidget();
+        MaterialDatePicker picker = getWidget(false);
+
+        // when / then
+        checkClear(picker);
+
+        // Standard
+        // given
+        attachWidget();
+
+        // when / then
+        checkClear(picker);
+    }
 
-        // when
+    protected void checkClear(MaterialDatePicker picker) {
         picker.setValue(DATE);
         picker.setError("error");
         picker.clear();
 
-        // then
         assertEquals("", picker.getDateInput().getElement().getInnerText());
         assertFalse(picker.getLabel().getElement().hasClassName(CssName.ACTIVE));
         assertFalse(picker.getDateInput().getElement().hasClassName(CssName.VALID));