Date and Time Input with DateField

The DateField component provides the means to display and input date and time. The field comes in two variations: PopupDateField, with a numeric input box and a popup calendar view, and InlineDateField, with the calendar view always visible. The DateField base class defaults to the popup variation.

The example below illustrates the use of the DateField baseclass, which is equivalent to the PopupDateField. We set the initial time of the date field to current time by using the default constructor of the java.util.Date class.

Java

// Create a DateField with the default style
DateField date = new DateField();
// Set the date and time to present
date.setValue(new Date());

The result is shown in DateField (PopupDateField) for Selecting Date and Time.

DateField (PopupDateField) for Selecting Date and Time

PopupDateField

The PopupDateField provides date input using a text box for the date and time. As the DateField defaults to this component, the use is exactly the same as described earlier. Clicking the handle right of the date opens a popup view for selecting the year, month, and day, as well as time. Also the Down key opens the popup. Once opened, the user can navigate the calendar using the cursor keys.

The date and time selected from the popup are displayed in the text box according to the default date and time format of the current locale, or as specified with setDateFormat(). The same format definitions are used for parsing user input.

Date and Time Format

The date and time are normally displayed according to the default format for the current locale (see “Locale”). You can specify a custom format with setDateFormat(). It takes a format string that follows the format of the SimpleDateFormat in Java.

Java

// Display only year, month, and day in ISO format
date.setDateFormat("yyyy-MM-dd");

The result is shown in Custom Date Format for PopupDateField.

Custom Date Format for PopupDateField

The same format specification is also used for parsing user-input date and time, as described later.

Handling Malformed User Input

A user can easily input a malformed or otherwise invalid date or time. DateField has two validation layers: first on the client-side and then on the server-side.

The validity of the entered date is first validated on the client-side, immediately when the input box loses focus. If the date format is invalid, the v-datefield-parseerror style is set. Whether this causes a visible indication of a problem depends on the theme. The built-in reindeer theme does not shown any indication by default, making server-side handling of the problem more convenient.

CSS

.mydate.v-datefield-parseerror .v-textfield {
    background: pink;
}

The setLenient(true) setting enables relaxed interpretation of dates, so that invalid dates, such as February 30th or March 0th, are wrapped to the next or previous month, for example.

The server-side validation phase occurs when the date value is sent to the server. If the date field is set in immediate state, it occurs immediately after the field loses focus. Once this is done and if the status is still invalid, an error indicator is displayed beside the component. Hovering the mouse pointer over the indicator shows the error message.

You can handle the errors by overriding the handleUnparsableDateString() method. The method gets the user input as a string parameter and can provide a custom parsing mechanism, as shown in the following example.

Java

// Create a date field with a custom parsing and a
// custom error message for invalid format
PopupDateField date = new PopupDateField("My Date") {
    @Override
    protected Date handleUnparsableDateString(String dateString)
    throws Property.ConversionException {
        // Try custom parsing
        String fields[] = dateString.split("/");
        if (fields.length >= 3) {
            try {
                int year  = Integer.parseInt(fields[0]);
                int month = Integer.parseInt(fields[1])-1;
                int day   = Integer.parseInt(fields[2]);
                GregorianCalendar c =
                    new GregorianCalendar(year, month, day);
                return c.getTime();
            } catch (NumberFormatException e) {
                throw new Property.
                    ConversionException("Not a number");
            }
        }
        // Bad date
        throw new Property.
            ConversionException("Your date needs two slashes");
    }
};
// Display only year, month, and day in slash-delimited format
date.setDateFormat("yyyy/MM/dd");
// Don't be too tight about the validity of dates
// on the client-side
date.setLenient(true);

The handler method must either return a parsed Date object or throw a ConversionException. Returning null will set the field value to null and clear the input box.

Customizing the Error Message

In addition to customized parsing, overriding the handler method for unparseable input is useful for internationalization and other customization of the error message. You can also use it for another way for reporting the errors, as is done in the example below:

Java

// Create a date field with a custom error message for invalid format
PopupDateField date = new PopupDateField("My Date") {
    @Override
    protected Date handleUnparsableDateString(String dateString)
    throws Property.ConversionException {
        // Have a notification for the error
        Notification.show(
                "Your date needs two slashes",
                Notification.TYPE_WARNING_MESSAGE);
        // A failure must always also throw an exception
        throw new Property.ConversionException("Bad date");
    }
};

If the input is invalid, you should always throw the exception; returning a null value would make the input field empty, which is probably undesired.

Input Prompt

Like other fields that have a text box, PopupDateField allows an input prompt that is visible until the user has input a value. You can set the prompt with setInputPrompt.

Java

PopupDateField date = new PopupDateField();
// Set the prompt
date.setInputPrompt("Select a date");
// Set width explicitly to accommodate the prompt
date.setWidth("10em");

The date field doesn’t automatically scale to accommodate the prompt, so you need to set it explicitly with setWidth().

The input prompt is not available in the DateField superclass.

CSS Style Rules

CSS

.v-datefield, v-datefield-popupcalendar {}
  .v-textfield, v-datefield-textfield {}
  .v-datefield-button {}

The top-level element of DateField and all its variants have v-datefield style. The base class and the PopupDateField also have the v-datefield-popupcalendar style.

In addition, the top-level element has a style that indicates the resolution, with v-datefield- basename and an extension, which is one of full, day, month, or year. The -full style is enabled when the resolution is smaller than a day. These styles are used mainly for controlling the appearance of the popup calendar.

The text box has v-textfield and v-datefield-textfield styles, and the calendar button v-datefield-button.

Once opened, the calendar popup has the following styles at the top level:

CSS

.v-datefield-popup {}
  .v-popupcontent {}
    .v-datefield-calendarpanel {}

The top-level element of the floating popup calendar has .v-datefield-popup style. Observe that the popup frame is outside the HTML structure of the component, hence it is not enclosed in the v-datefield element and does not include any custom styles. The content in the v-datefield-calendarpanel is the same as in InlineDateField, as described in InlineDateField.

InlineDateField

The InlineDateField provides a date picker component with a month view. The user can navigate months and years by clicking the appropriate arrows. Unlike with the pop-up variant, the month view is always visible in the inline field.

Java

// Create a DateField with the default style
InlineDateField date = new InlineDateField();
// Set the date and time to present
date.setValue(new java.util.Date());

The result is shown in Example of the InlineDateField.

Example of the InlineDateField

The user can also navigate the calendar using the cursor keys.

CSS Style Rules

CSS

.v-datefield {}
  .v-datefield-calendarpanel {}
    .v-datefield-calendarpanel-header {}
      .v-datefield-calendarpanel-prevyear {}
      .v-datefield-calendarpanel-prevmonth {}
      .v-datefield-calendarpanel-month {}
      .v-datefield-calendarpanel-nextmonth {}
      .v-datefield-calendarpanel-nextyear {}
    .v-datefield-calendarpanel-body {}
      .v-datefield-calendarpanel-weekdays,
      .v-datefield-calendarpanel-weeknumbers {}
        .v-first {}
        .v-last {}
      .v-datefield-calendarpanel-weeknumber {}
      .v-datefield-calendarpanel-day {}
    .v-datefield-calendarpanel-time {}
      .v-datefield-time {}
        .v-select {}
        .v-label {}

The top-level element has the v-datefield style. In addition, the top-level element has a style name that indicates the resolution of the calendar, with v-datefield- basename and an extension, which is one of full, day, month, or year. The -full style is enabled when the resolution is smaller than a day.

The v-datefield-calendarpanel-weeknumbers and v-datefield-calendarpanel-weeknumber styles are enabled when the week numbers are enabled. The former controls the appearance of the weekday header and the latter the actual week numbers.

The other style names should be self-explanatory. For weekdays, the v-first and v-last styles allow making rounded endings for the weekday bar.

Date and Time Resolution

In addition to display a calendar with dates, DateField can also display the time in hours and minutes, or just the month or year. The visibility of the input components is controlled by time resolution, which you can set with setResolution(). The method takes as its parameters the lowest visible component, DateField.Resolution.DAY for just dates and DateField.Resolution.MIN for dates with time in hours and minutes. Please see the API Reference for the complete list of resolution parameters.

DateField Locale

The date and time are displayed according to the locale of the user, as reported by the browser. You can set a custom locale with the setLocale() method of AbstractComponent, as described in “Locale”. Only Gregorian calendar is supported.

Week Numbers

You can enable week numbers in a date field with setShowISOWeekNumbers(). The numbers are shown in a column on the left side of the field.

Java

df.setShowISOWeekNumbers(true);

The supported numbering is defined in the ISO 8601 standard. Note that the ISO standard applies only to calendar locales where the week starts on Monday. This is not the case in many countries, such as Americas (North and South), many East-Asian countries, and some African countries, where the week starts on Sunday, nor in some North African and Middle-Eastern countries, where the week begins on Saturday. In such locales, the week numbers are not displayed.