Actionscript Cookbook

8.27. Responding to User Text Entry

Problem

You want to perform a task when the content of a text field is modified by user input.

Solution

Assign a function definition to the text field’s onChanged( ) event handler method. Alternatively, you can use a listener object with a defined onChanged( ) method and register it with the text field using addListener( ).

Discussion

You can specify actions to be performed each time the content of a text field is changed by user input, whether that change be deleting or cutting characters, typing in characters, or pasting characters. You can define the text field’s onChanged( ) event handler method:

myTextField.onChanged = function (  ) {
  trace("the value has been modified");
};

When a user makes any change to the value of an input text field with an onChanged( ) handler defined, the actions defined in the onChanged( ) handler are executed.

You can also define an onChanged( ) method for a listener object (or listener objects). If multiple objects need to be updated when a change occurs in the input text field’s value, you should register those objects as listeners. You should define an onChanged( ) method for the listener object and then register the listener with the text field’s addListener( ) method. The addListener( ) method takes a reference to the listener object. For example:

myListener = new Object(  );
myListener.onChanged = function (  ) {
  // Actions go here.
};
myTextField.addListener(myListener);

You can use addListener( ) to register as many ...