CODEWITHSUNDEEP
javaawt
JohnnyLambada
JohnnyLambada

Reputation: 12826

What is java.awt.Component.getName() and setName() used for?

What is java.awt.Component.getName() used for? It always seems to be null in the applications I build with NetBeans. I'm thinking of storing some help text per component in it -- I don't want to use the tooltip, I have another panel where I'll show the help text.

Upvotes: 23

Views: 25504

Answers (9)

Tural
Tural

Reputation: 1

I have searched many answers for getting name and i think this is the only easy solution 

public static void main(String[] args) {
    ActionListener actionListener = new ActionListener() {
        public void actionPerformed(ActionEvent actionEvent) {
            String name = actionEvent.getSource().toString();
            UserReaction(ObjectName.getComponentVariableName(name), "null");
        }
    };
    Button calculate_btn = new Button("Calculate");
    calculate_btn.setName("Calculate");
    calculate_btn.addActionListener(actionListener);
}

private static void UserReaction(String objectName) {
    if (objectName.equals("Calculate")) {
        //do something;         
    }
}static public String getComponentVariableName(String name) {
    String res = (name.substring(name.indexOf("[") + 1));
    res = res.split(",")[0];
    return res;
}

Upvotes: -1

Vivavinyl
Vivavinyl

Reputation:

The component.getName() method is mostly used with listeners. If you set the name of a component (component.setName(name)) you can call to that specific component from within a method of a Listener.

Example:

public void someMethodOfsomeListener(SomeEvent e){
   if (e.getComponent().getName().equals(component.getName())
      //do stuff...
}

Be aware that you have to explicitly set the name of the component, otherwise it will return null.

Upvotes: 1

Simulant
Simulant

Reputation: 20132

FEST uses the name of a Component to identify it in testcases.

Upvotes: 2

user178176
user178176

Reputation:

This is what I use getName() for:

    Frame[] frames = JFrame.getFrames();

    for (int i = 0; i < frames.length; ++i) {

        //get the frame
        Frame frame = frames[i];

        if (frame.getName().equals(frameName)) {

            //make the frame visible
            frame.setVisible(true);

            //focus the frame
            frame.requestFocus();

            //found
            return;

        }

    }

Upvotes: 0

David
David

Reputation:

I use it for handling listeners in one single class apart. I receive as a parameter the component which contains my object.addListener not as a container but as the class that contains that object. Thanks Vivavinyl for the the tip of setting the name first. It was useful and worked.

Upvotes: 0

JohnnyLambada
JohnnyLambada

Reputation: 12826

Herman Lintvelt's answer ended up being the correct one for my app.

I created a resource bundle named HelpText.properties. It contains name=value pairs. I setName()d each of my Components with the "name" from the name=value pair. I then used a the frame's getGlassPane() to capture all mouse movements. When a mouse runs over a named component, it looks up the name in the bundle, displays help if available and forwards the mouse motion to along to the actual Component.

Whew. Only 2 days worth of dinking around. I'm finally starting to get used to Java :)

Upvotes: 2

Herman Lintvelt
Herman Lintvelt

Reputation: 1791

Component.setName(..) is used in the JDK mostly by the look and feel implementation classes to set ID-like strings for each component, e.g. BasicOptionPaneUI might call it on a button component to set its name to "OptionPane.button".

The getName() is used in toString() methods, when setting the names of child components inside a Composite/parent Component and in AWT and Swing debug logging code. I suspect strongly that the getName() method is also used by some AWT/Swing testing frameworks.

So if you're not dependent on any of the above uses of getName(), you might try using it for your help messages, though I would not recommend it.

Maybe you should reconsider your design? Use the name to do some lookup in a hashmap that loads the help text from a resource bundle?

Upvotes: 21

Paul Tomblin
Paul Tomblin

Reputation: 182840

Also, since I think java.awt.Component is a heavyweight object in X, programs like xwininfo and xwd might allow you to specify it by name.

I just tried it with a JFrame, and setName didn't set the name of the window, the window was named by the string I passed in the constructor. But I don't have any awt-only example code to test with, so I could be wrong about what I wrote above.

Upvotes: 0

AdamC
AdamC

Reputation: 16303

I haven't seen it used for anything by the framework. Its useful if you have components being passed in to a method so you can ask their name to decide how to handle them. Also, many UI testing frameworks use this to allow you to refer to the components by name in the testing scripts. I don't see any reason you can't use it for help text though.

Upvotes: 7

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