Home Page
>
Creating a GUI with JFC/Swing
>
Using Swing Components
How to Use Tool Tips
Creating a tool tip for any JComponent
object is easy.
Use the setToolTipText method
to set up a tool tip for the component.
For example, to add tool tips to three buttons,
you add only three lines of code:
b1.setToolTipText("Click this button to disable the middle button.");
b2.setToolTipText("This middle button does not react when you click it.");
b3.setToolTipText("Click this button to enable the middle button.");
When the user of the program
pauses with the cursor over any of the program's buttons,
the tool tip for the button comes up.
You can see this by running the ButtonDemo example,
which is explained in
How to Use Buttons, Check Boxes, and Radio Buttons.
Here is a picture of the tool tip
that appears when the cursor pauses over the left button
in the ButtonDemo example.
For components
such as tabbed panes
that have multiple parts,
it often makes sense to vary the tool tip text
to reflect the part of the component
under the cursor.
For example,
a tabbed pane might use this feature
to explain what will happen when you click the tab
under the cursor.
When you implement a tabbed pane,
you can specify the tab-specific tool tip text in an argument passed to
the addTab or setToolTipTextAt method.
Even in components that have no API for setting part-specific tool tip text,
you can generally do the job yourself.
If the component supports renderers,
then you can set the tool tip text on a custom renderer.
The
table and
tree sections
provide examples of tool tip text
determined by a custom renderer.
An alternative that works for all JComponents
is creating a subclass of the component
and overriding its
getToolTipText(MouseEvent) method.
Most of the API you need in order to set up tool tips
belongs to the JComponent class,
and thus is inherited by most Swing components.
More tool tip API can be found in individual classes
such as JTabbedPane.
In general, those APIs are sufficient
for specifying and displaying tool tips;
you usually do not need to deal directly with the implementing classes
JToolTip and
ToolTipManager.
The following table lists
the tool tip API in the JComponent class.
For information on individual components' support
for tool tips,
see the how-to section for the component in question.
Tool Tip API in the JComponent class
| Method
|
Purpose
|
|
setToolTipText(String) |
If the specified string is not null,
then this method registers the component
as having a tool tip
and, when displayed,
gives the tool tip
the specified text.
If the argument is null,
then this method turns off the tool tip for this component.
|
|
String getToolTipText() |
Returns the string
that was previously specified with setToolTipText.
|
|
String getToolTipText(MouseEvent) |
By default, returns the same value returned by
getToolTipText().
Multi-part components such as
JTabbedPane,
JTable,
and JTree
override this method to return a string
associated with the mouse event location.
For example, each tab in a tabbed pane
can have different tool tip text.
|
|
Point getToolTipLocation(MouseEvent) |
Returns the location (in the receiving component's coordinate system)
where the upper left corner of the component's tool tip appears.
The argument is the event that caused the tool tip
to be shown.
The default return value is null,
which tells the Swing system to choose a location.
|
This table lists some examples that use tool tips
and points to where those examples are described.
