Class: Fox::FXDataTarget

Inherits:
FXObject show all
Includes:
Responder2
Defined in:
rdoc-sources/FXDataTarget.rb,
lib/fox16/core.rb,
lib/fox16/responder2.rb

Overview

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Responder2

#connect

Methods inherited from FXObject

#bind, #handle, #load, #save, subclasses

Constructor Details

#initialize(value = nil, target = nil, selector = 0) ⇒ FXDataTarget

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.



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# File 'rdoc-sources/FXDataTarget.rb', line 62

def initialize(value=nil, target=nil, selector=0) # :yields: theDataTarget
end

Instance Attribute Details

#selector ⇒ Object

The message identifier for this data target [Integer]



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# File 'rdoc-sources/FXDataTarget.rb', line 51

def selector
  @selector
end

#target ⇒ Object

The message target object for this data target Fox::FXObject



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# File 'rdoc-sources/FXDataTarget.rb', line 48

def target
  @target
end

#value ⇒ Object

The data target’s current value [Object]



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# File 'rdoc-sources/FXDataTarget.rb', line 54

def value
  @value
end

Instance Method Details

#to_s ⇒ Object

Returns the stringified representation of this data target’s value.



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# File 'lib/fox16/core.rb', line 82

def to_s
  value.to_s
end