Class Fox::FXDataTarget
In: rdoc-sources/FXDataTarget.rb
Parent: FXObject

A data target allows a valuator widget such as an FXSlider or FXTextField to be directly connected with a variable in the program. Whenever the valuator control changes, the variable connected through the data target is automatically updated; conversely, whenever the program changes a variable, all the connected valuator widgets will be updated to reflect this new value on the display. For example:

    data = FXDataTarget.new("Some Text")
    textfield = FXTextField.new(p, 12, data, FXDataTarget::ID_VALUE)

Data targets also allow connecting other kinds of widgets (like FXRadioButton and FXMenuCommand) to a variable. In this case, the new value of the connected variable is computed by subtracting FXDataTarget::ID_OPTION from the message identifier. For example, to tie a group of radio buttons to a single data target‘s value (so that the buttons are mutually exclusive), use code like this:

    data = FXDataTarget.new(0)
    radio1 = FXRadioButton.new(p, "1st choice", data, FXDataTarget::ID_OPTION)
    radio2 = FXRadioButton.new(p, "2nd choice", data, FXDataTarget::ID_OPTION + 1)
    radio3 = FXRadioButton.new(p, "3rd choice", data, FXDataTarget::ID_OPTION + 2)

Note that if you‘d like the data target to "forward" its SEL_COMMAND or SEL_CHANGED to some other target object after it has updated the data target value, you can do that just as you would for any other widget. For example, continuing the previous code snippet:

    data.connect(SEL_COMMAND) {
      puts "The new data target value is #{data.value}"
    }

Events

The following messages are sent by FXDataTarget to its target:

SEL_COMMAND:Sent after the data target processes a SEL_COMMAND message itself
SEL_CHANGED:Sent after the data target processes a SEL_CHANGED message itself

Message identifiers

ID_VALUE:Causes the FXDataTarget to ask sender for value
ID_OPTION:ID_OPTION+i will set the value to i, where -10000 <= i <= 10000

Methods

new  

Attributes

selector  [RW]  The message identifier for this data target [Integer]
target  [RW]  The message target object for this data target [FXObject]
value  [RW]  The data target‘s current value [Object]

Public Class methods

Return a new FXDataTarget instance, initialized with the specified value. If the optional message target object and message identifier (tgt and sel) are specified, the data target will forward the SEL_COMMAND or SEL_COMMAND to this other target.

[Validate]