ToolTips.
* For example, any Swing component can use the JComponent
* setToolTipText method to specify the text
* for a standard tooltip. A component that wants to create a custom
* ToolTip
* display can override JComponent's createToolTip
* method and use a subclass of this class.
* * See How to Use Tool Tips * in The Java Tutorial * for further documentation. *
* Warning: Swing is not thread safe. For more * information see Swing's Threading * Policy. *
* Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeansTM
* has been added to the java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*
* @see JComponent#setToolTipText
* @see JComponent#createToolTip
* @author Dave Moore
* @author Rich Shiavi
*/
public class JToolTip extends JComponent implements Accessible {
/**
* @see #getUIClassID
* @see #readObject
*/
private static final String uiClassID = "ToolTipUI";
String tipText;
JComponent component;
/** Creates a tool tip. */
public JToolTip() {
setOpaque(true);
updateUI();
}
/**
* Returns the L&F object that renders this component.
*
* @return the ToolTipUI object that renders this component
*/
public ToolTipUI getUI() {
return (ToolTipUI)ui;
}
/**
* Resets the UI property to a value from the current look and feel.
*
* @see JComponent#updateUI
*/
public void updateUI() {
setUI((ToolTipUI)UIManager.getUI(this));
}
/**
* Returns the name of the L&F class that renders this component.
*
* @return the string "ToolTipUI"
* @see JComponent#getUIClassID
* @see UIDefaults#getUI
*/
public String getUIClassID() {
return uiClassID;
}
/**
* Sets the text to show when the tool tip is displayed.
* The string tipText may be null.
*
* @param tipText the String to display
* @beaninfo
* preferred: true
* bound: true
* description: Sets the text of the tooltip
*/
public void setTipText(String tipText) {
String oldValue = this.tipText;
this.tipText = tipText;
firePropertyChange("tiptext", oldValue, tipText);
if (!Objects.equals(oldValue, tipText)) {
revalidate();
repaint();
}
}
/**
* Returns the text that is shown when the tool tip is displayed.
* The returned value may be null.
*
* @return the String that is displayed
*/
public String getTipText() {
return tipText;
}
/**
* Specifies the component that the tooltip describes.
* The component c may be null
* and will have no effect.
*
* This is a bound property.
*
* @param c the JComponent being described
* @see JComponent#createToolTip
* @beaninfo
* bound: true
* description: Sets the component that the tooltip describes.
*/
public void setComponent(JComponent c) {
JComponent oldValue = this.component;
component = c;
firePropertyChange("component", oldValue, c);
}
/**
* Returns the component the tooltip applies to.
* The returned value may be null.
*
* @return the component that the tooltip describes
*
* @see JComponent#createToolTip
*/
public JComponent getComponent() {
return component;
}
/**
* Always returns true since tooltips, by definition,
* should always be on top of all other windows.
*/
// package private
boolean alwaysOnTop() {
return true;
}
/**
* See readObject and writeObject
* in JComponent for more
* information about serialization in Swing.
*/
private void writeObject(ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
if (getUIClassID().equals(uiClassID)) {
byte count = JComponent.getWriteObjCounter(this);
JComponent.setWriteObjCounter(this, --count);
if (count == 0 && ui != null) {
ui.installUI(this);
}
}
}
/**
* Returns a string representation of this JToolTip.
* This method
* is intended to be used only for debugging purposes, and the
* content and format of the returned string may vary between
* implementations. The returned string may be empty but may not
* be null.
*
* @return a string representation of this JToolTip
*/
protected String paramString() {
String tipTextString = (tipText != null ?
tipText : "");
return super.paramString() +
",tipText=" + tipTextString;
}
/////////////////
// Accessibility support
////////////////
/**
* Gets the AccessibleContext associated with this JToolTip.
* For tool tips, the AccessibleContext takes the form of an
* AccessibleJToolTip.
* A new AccessibleJToolTip instance is created if necessary.
*
* @return an AccessibleJToolTip that serves as the
* AccessibleContext of this JToolTip
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleJToolTip();
}
return accessibleContext;
}
/**
* This class implements accessibility support for the
* JToolTip class. It provides an implementation of the
* Java Accessibility API appropriate to tool tip user-interface elements.
*
* Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeansTM
* has been added to the java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*/
protected class AccessibleJToolTip extends AccessibleJComponent {
/**
* Get the accessible description of this object.
*
* @return a localized String describing this object.
*/
public String getAccessibleDescription() {
String description = accessibleDescription;
// fallback to client property
if (description == null) {
description = (String)getClientProperty(AccessibleContext.ACCESSIBLE_DESCRIPTION_PROPERTY);
}
if (description == null) {
description = getTipText();
}
return description;
}
/**
* Get the role of this object.
*
* @return an instance of AccessibleRole describing the role of the
* object
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.TOOL_TIP;
}
}
}