如果在GXT中某些条件失败，如何将DateField值设置为Previous Value

Question

I am creating a DateField and adding listener to it.If certain conditions fails I need to reset the value of DateField with previous value which is there in that field.Below is my code

final DateField dateField1 = new DateField();
    dateField1.getPropertyEditor().setFormat(DateTimeFormat.getFormat("dd/MMM/yyyy")); 
    dateField1.getDatePicker().addListener(Events.Select, new Listener<DatePickerEvent>() {

        @Override
        public void handleEvent(DatePickerEvent dpe) {

        //  Window.alert("Getting Roster Date here-->"+grid.getColumnModel().);
        Window.alert("Getting RosterDate-->"+   caseStoreModule.getModifiedRecords().get(0).get("rosterDate"));
         if(caseStoreModule.getModifiedRecords().get(0).get("rosterDate")!=null){
                DateTimeFormat format = DateTimeFormat.getFormat("dd/MMM/yyyy");
                rosterdate=format.parse(caseStoreModule.getModifiedRecords().get(0).get("rosterDate").toString());
                nextdate.setTime(rosterdate.getTime()+(1000*60*60*24));
                prevdate.setTime(rosterdate.getTime()-(1000*60*60*24));
            }
        checkInDate=(Date)(dateField1.getValue());
        if(checkInDate.getTime()<rosterdate.getTime() || checkInDate.getTime()>nextdate.getTime()){
            MsgBox.info("Enter valid Check In Date");
           dateField1.setValue();//here i need to reset the value to the     previous value.
            return ;
        }



        }
    });

If the if condition is true,then I need to put the previous value which is there in the Field instead of reseting it.Please suggest how to do this.

Answer 1

One solution is having a String variable that holds the field value before doing any manipulation. So if you need to reset the field just use it. Something like this

String tmpStringValue = dateField1.getValue();
...
if(something went wrong){
   dateField1.setValue(tmpStringValue );
}

Answer 2

You can store values as an attribute of Element .

At first time this attribute oldValue will be blank. Set this attribute every time if validation is successful.

For more information read inline comments.

Here is the sample code:

dateField1.getCell().getDatePicker().addValueChangeHandler(new ValueChangeHandler<Date>() {

    @Override
    public void onValueChange(ValueChangeEvent<Date> event) {

        DateTimeFormat format = DateTimeFormat.getFormat("yyyy-dd-MM");
        String oldValue = dateField1.getElement().getAttribute("oldValue");

        if (oldValue == null || oldValue.length() == 0) {
            // initially date field is empty
            dateField1.getElement().setAttribute("oldValue",
                    format.format(event.getValue()));
        } else {
            Date oldDate = format.parse(oldValue);
            Date newDate = event.getValue();

            // you validation logic
            if (oldDate.getTime() < newDate.getTime()) {
                // revert back to last value if validation is failed
                dateField1.getCell().getDatePicker().setValue(oldDate);
            } else {
                // set the old value with new one 
                dateField1.getElement().setAttribute("oldValue",
                        format.format(event.getValue()));
            }
        }

    }
});

Call below line if value is initially populated by its default value just after setting the value.

dateField1.getElement().setAttribute("oldValue",
                    format.format(event.getValue()));

Answer 3

In GXT, every Field has a setOriginalValue(D originalValue) method which could help you in this matter too. You can always return to the original value by reset() ing the Field. Please keep in mind that reset() will clear the validation messages too!

How to use it in situations like this?

1. Set the original value when the entered value is validated fine
2. Call Field.reset() , if anything went wrong to reload the last working value in your field.