javax.swing

Interface ButtonModel

  • All Superinterfaces:
    ItemSelectable
    All Known Implementing Classes:
    DefaultButtonModel, JToggleButton.ToggleButtonModel 

    public interface ButtonModel
extends ItemSelectable
    State model for buttons.

    This model is used for regular buttons, as well as check boxes and radio buttons, which are special kinds of buttons. In practice, a button's UI takes the responsibility of calling methods on its model to manage the state, as detailed below:

    In simple terms, pressing and releasing the mouse over a regular button triggers the button and causes and ActionEvent to be fired. The same behavior can be produced via a keyboard key defined by the look and feel of the button (typically the SPACE BAR). Pressing and releasing this key while the button has focus will give the same results. For check boxes and radio buttons, the mouse or keyboard equivalent sequence just described causes the button to become selected.

    In details, the state model for buttons works as follows when used with the mouse:
    Pressing the mouse on top of a button makes the model both armed and pressed. As long as the mouse remains down, the model remains pressed, even if the mouse moves outside the button. On the contrary, the model is only armed while the mouse remains pressed within the bounds of the button (it can move in or out of the button, but the model is only armed during the portion of time spent within the button). A button is triggered, and an ActionEvent is fired, when the mouse is released while the model is armed - meaning when it is released over top of the button after the mouse has previously been pressed on that button (and not already released). Upon mouse release, the model becomes unarmed and unpressed.

    In details, the state model for buttons works as follows when used with the keyboard:
    Pressing the look and feel defined keyboard key while the button has focus makes the model both armed and pressed. As long as this key remains down, the model remains in this state. Releasing the key sets the model to unarmed and unpressed, triggers the button, and causes an ActionEvent to be fired.

    • Method Summary

      Modifier and Type Method and Description
      void addActionListener(ActionListener l)
      Adds an ActionListener to the model.
      void addChangeListener(ChangeListener l)
      Adds a ChangeListener to the model.
      void addItemListener(ItemListener l)
      Adds an ItemListener to the model.
      String getActionCommand()
      Returns the action command string for the button.
      int getMnemonic()
      Gets the keyboard mnemonic for the button.
      boolean isArmed()
      Indicates partial commitment towards triggering the button.
      boolean isEnabled()
      Indicates if the button can be selected or triggered by an input device, such as a mouse pointer.
      boolean isPressed()
      Indicates if the button is pressed.
      boolean isRollover()
      Indicates that the mouse is over the button.
      boolean isSelected()
      Indicates if the button has been selected.
      void removeActionListener(ActionListener l)
      Removes an ActionListener from the model.
      void removeChangeListener(ChangeListener l)
      Removes a ChangeListener from the model.
      void removeItemListener(ItemListener l)
      Removes an ItemListener from the model.
      void setActionCommand(String s)
      Sets the action command string that gets sent as part of the ActionEvent when the button is triggered.
      void setArmed(boolean b)
      Marks the button as armed or unarmed.
      void setEnabled(boolean b)
      Enables or disables the button.
      void setGroup(ButtonGroup group)
      Identifies the group the button belongs to -- needed for radio buttons, which are mutually exclusive within their group.
      void setMnemonic(int key)
      Sets the keyboard mnemonic (shortcut key or accelerator key) for the button.
      void setPressed(boolean b)
      Sets the button to pressed or unpressed.
      void setRollover(boolean b)
      Sets or clears the button's rollover state
      void setSelected(boolean b)
      Selects or deselects the button.

    • Method Detail

      • isArmed

        boolean isArmed()
        Indicates partial commitment towards triggering the button.
        Returns:
        true if the button is armed, and ready to be triggered
        See Also:
        setArmed(boolean)

      • isSelected

        boolean isSelected()
        Indicates if the button has been selected. Only needed for certain types of buttons - such as radio buttons and check boxes.
        Returns:
        true if the button is selected

      • isEnabled

        boolean isEnabled()
        Indicates if the button can be selected or triggered by an input device, such as a mouse pointer.
        Returns:
        true if the button is enabled

      • isPressed

        boolean isPressed()
        Indicates if the button is pressed.
        Returns:
        true if the button is pressed

      • isRollover

        boolean isRollover()
        Indicates that the mouse is over the button.
        Returns:
        true if the mouse is over the button

      • setArmed

        void setArmed(boolean b)
        Marks the button as armed or unarmed.
        Parameters:
        b - whether or not the button should be armed

      • setSelected

        void setSelected(boolean b)
        Selects or deselects the button.
        Parameters:
        b - true selects the button, false deselects the button

      • setEnabled

        void setEnabled(boolean b)
        Enables or disables the button.
        Parameters:
        b - whether or not the button should be enabled
        See Also:
        isEnabled()

      • setPressed

        void setPressed(boolean b)
        Sets the button to pressed or unpressed.
        Parameters:
        b - whether or not the button should be pressed
        See Also:
        isPressed()

      • setRollover

        void setRollover(boolean b)
        Sets or clears the button's rollover state
        Parameters:
        b - whether or not the button is in the rollover state
        See Also:
        isRollover()

      • setMnemonic

        void setMnemonic(int key)
        Sets the keyboard mnemonic (shortcut key or accelerator key) for the button.
        Parameters:
        key - an int specifying the accelerator key

      • getMnemonic

        int getMnemonic()
        Gets the keyboard mnemonic for the button.
        Returns:
        an int specifying the accelerator key
        See Also:
        setMnemonic(int)

      • setActionCommand

        void setActionCommand(String s)
        Sets the action command string that gets sent as part of the ActionEvent when the button is triggered.
        Parameters:
        s - the String that identifies the generated event
        See Also:
        getActionCommand(), ActionEvent.getActionCommand()

      • setGroup

        void setGroup(ButtonGroup group)
        Identifies the group the button belongs to -- needed for radio buttons, which are mutually exclusive within their group.
        Parameters:
        group - the ButtonGroup the button belongs to

      • addActionListener

        void addActionListener(ActionListener l)
        Adds an ActionListener to the model.
        Parameters:
        l - the listener to add

      • removeActionListener

        void removeActionListener(ActionListener l)
        Removes an ActionListener from the model.
        Parameters:
        l - the listener to remove

      • addChangeListener

        void addChangeListener(ChangeListener l)
        Adds a ChangeListener to the model.
        Parameters:
        l - the listener to add

      • removeChangeListener

        void removeChangeListener(ChangeListener l)
        Removes a ChangeListener from the model.
        Parameters:
        l - the listener to remove