All geek questions in one place

Can I use JCheckbox to display a “mixed state”,

In the windows, you can display a gray JCheckbox window to show that the collection of data that it represents not all elements has the same value.

Is this possible with JCheckBox? How can I do it? (Hope there is a way not to override it)

thanks

+4
source share
3 answers

My colleague who this question came from thinking about it;

  • Create a dummy JCheckBox that is disabled and selected. Set the same size as the real one.
  • Create an icon that "the drawing method actually draws the JCheckbox dummy."
  • Set the original JCheckBox 'icon to draw a layout.
  • Remove the icon as soon as you click JCheckBox.

++ No overridden JCheckBox

- not real tri-state combo

I think he is satisfied. thanks for the help

0
source

This is possible with some work.

I have this code a few years ago. Based on some examples that I found on the Internet, but I can not find the link to the original creator, so I apologize

import javax.swing.*; import javax.swing.event.ChangeListener; import javax.swing.plaf.ActionMapUIResource; import java.awt.event.*; /** * Maintenance tip - There were some tricks to getting this code * working: * * 1. You have to overwite addMouseListener() to do nothing * 2. You have to add a mouse event on mousePressed by calling * super.addMouseListener() * 3. You have to replace the UIActionMap for the keyboard event * "pressed" with your own one. * 4. You have to remove the UIActionMap for the keyboard event * "released". * 5. You have to grab focus when the next state is entered, * otherwise clicking on the component won't get the focus. * 6. You have to make a TristateDecorator as a button model that * wraps the original button model and does state management. */ public class TristateCheckBox extends JCheckBox { /** This is a type-safe enumerated type */ public static class State { private State() { } } public static final State NOT_SELECTED = new State(); public static final State SELECTED = new State(); public static final State DONT_CARE = new State(); private final TristateDecorator model; public TristateCheckBox(String text, Icon icon, State initial){ super(text, icon); // Add a listener for when the mouse is pressed super.addMouseListener(new MouseAdapter() { public void mousePressed(MouseEvent e) { grabFocus(); model.nextState(); } }); // Reset the keyboard action map ActionMap map = new ActionMapUIResource(); map.put("pressed", new AbstractAction() { public void actionPerformed(ActionEvent e) { grabFocus(); model.nextState(); } }); map.put("released", null); SwingUtilities.replaceUIActionMap(this, map); // set the model to the adapted model model = new TristateDecorator(getModel()); setModel(model); setState(initial); } public TristateCheckBox(String text, State initial) { this(text, null, initial); } public TristateCheckBox(String text) { this(text, DONT_CARE); } public TristateCheckBox() { this(null); } /** No one may add mouse listeners, not even Swing! */ public void addMouseListener(MouseListener l) { } /** * Set the new state to either SELECTED, NOT_SELECTED or * DONT_CARE. If state == null, it is treated as DONT_CARE. */ public void setState(State state) { model.setState(state); } /** Return the current state, which is determined by the * selection status of the model. */ public State getState() { return model.getState(); } public void setSelected(boolean b) { if (b) { setState(SELECTED); } else { setState(NOT_SELECTED); } } /** * Exactly which Design Pattern is this? Is it an Adapter, * a Proxy or a Decorator? In this case, my vote lies with the * Decorator, because we are extending functionality and * "decorating" the original model with a more powerful model. */ private class TristateDecorator implements ButtonModel { private final ButtonModel other; private TristateDecorator(ButtonModel other) { this.other = other; } private void setState(State state) { if (state == NOT_SELECTED) { other.setArmed(false); setPressed(false); setSelected(false); } else if (state == SELECTED) { other.setArmed(false); setPressed(false); setSelected(true); } else { // either "null" or DONT_CARE other.setArmed(true); setPressed(true); setSelected(true); } } /** * The current state is embedded in the selection / armed * state of the model. * * We return the SELECTED state when the checkbox is selected * but not armed, DONT_CARE state when the checkbox is * selected and armed (grey) and NOT_SELECTED when the * checkbox is deselected. */ private State getState() { if (isSelected() && !isArmed()) { // normal black tick return SELECTED; } else if (isSelected() && isArmed()) { // don't care grey tick return DONT_CARE; } else { // normal deselected return NOT_SELECTED; } } /** We rotate between NOT_SELECTED, SELECTED and DONT_CARE.*/ private void nextState() { State current = getState(); if (current == NOT_SELECTED) { setState(SELECTED); } else if (current == SELECTED) { setState(DONT_CARE); } else if (current == DONT_CARE) { setState(NOT_SELECTED); } } /** Filter: No one may change the armed status except us. */ public void setArmed(boolean b) { } /** We disable focusing on the component when it is not * enabled. */ public void setEnabled(boolean b) { setFocusable(b); other.setEnabled(b); } /** All these methods simply delegate to the "other" model * that is being decorated. */ public boolean isArmed() { return other.isArmed(); } public boolean isSelected() { return other.isSelected(); } public boolean isEnabled() { return other.isEnabled(); } public boolean isPressed() { return other.isPressed(); } public boolean isRollover() { return other.isRollover(); } public void setSelected(boolean b) { other.setSelected(b); } public void setPressed(boolean b) { other.setPressed(b); } public void setRollover(boolean b) { other.setRollover(b); } public void setMnemonic(int key) { other.setMnemonic(key); } public int getMnemonic() { return other.getMnemonic(); } public void setActionCommand(String s) { other.setActionCommand(s); } public String getActionCommand() { return other.getActionCommand(); } public void setGroup(ButtonGroup group) { other.setGroup(group); } public void addActionListener(ActionListener l) { other.addActionListener(l); } public void removeActionListener(ActionListener l) { other.removeActionListener(l); } public void addItemListener(ItemListener l) { other.addItemListener(l); } public void removeItemListener(ItemListener l) { other.removeItemListener(l); } public void addChangeListener(ChangeListener l) { other.addChangeListener(l); } public void removeChangeListener(ChangeListener l) { other.removeChangeListener(l); } public Object[] getSelectedObjects() { return other.getSelectedObjects(); } } }
+1
source

Source: https://habr.com/ru/post/1300061/

More articles:


All Articles