Since
input text fields are often used for forms or dialog boxes in applications, you
may want to limit the types of characters a user can enter in a
text field, or even keep the text hidden —for example, for a password.
The flash.text.TextField class has a
displayAsPassword
property
and a
restrict
property that you can set to control
user input.
The
displayAsPassword
property simply hides
the text (displaying it as a series of asterisks) as the user types
it. When
displayAsPassword
is set to
true
,
the Cut and Copy commands and their corresponding keyboard shortcuts do
not function. As the following example shows, you assign the
displayAsPassword
property
just as you would other properties, such as background and color:
myTextBox.type = TextFieldType.INPUT;
myTextBox.background = true;
myTextBox.displayAsPassword = true;
addChild(myTextBox);
The
restrict
property is a little more complicated
since you must specify which characters the user is allowed to type
in an input text field. You can allow specific letters, numbers,
or ranges of letters, numbers, and characters. The following code
allows the user to enter only uppercase letters (and not numbers or
special characters) in the text field:
myTextBox.restrict = "A-Z";
ActionScript 3.0 uses hyphens to define ranges, and carets to
define excluded characters. For more information about defining
what is restricted in an input text field, see the
flash.text.TextField.restrict
property
entry in the ActionScript 3.0 Reference.
Note:
If you use the
flash.text.TextField.restrict
property,
the runtime automatically converts restricted letters to the allowed
case. If you use the
fl.text.TLFTextField.restrict
property
(that is, if you use a TLF text field), the runtime ignores restricted
letters.