blackberry ButtonField application sample

Question

I am very new in black berry application.

now trying to create a calculator in blackberry using eclipse:

so i have added a button (ButtonField), my first target is when press this button i want display

"hi.. now you can try with text field."

here i put my code, please go through it.

Launcher.java

public class Launcher extends UiApplication {
    public static void main(String[] args) {
        Launcher theApp = new Launcher();
        theApp.enterEventDispatcher();
   }
   private Launcher()
   {
       this.pushScreen(new MainScrn());
   }

}

MainScrn .java

public class MainScrn extends MainScreen implements FieldChangeListener {
    public MainScrn() {
        LabelField lf_hello = new LabelField();
        lf_hello.setText("Hello, World!");
        lf_hello.setBackground(BackgroundFactory.createSolidBackground(124));
        ButtonField mySubmitButton = new ButtonField("clickMe");
        mySubmitButton.setChangeListener(this);
        this.add(lf_hello);
        this.add(mySubmitButton);
    }

    public void fieldChanged(Field field, int context) {
        System.out.println("hi.. now you can try with text field");

    }
}

hello whats the wrong on this. ? pls help.. it will quite simple for you, but me not now ?

Answer 1

Check this out.

public final class MyScreen extends MainScreen implements FieldChangeListener
{
/**
 * Creates a new MyScreen object
 */

LabelField lbl = new LabelField("hi.. now you can try with text field.");
ButtonField bf = new ButtonField("Click Me",ButtonField.CONSUME_CLICK);
public MyScreen()
{        
    // Set the displayed title of the screen       
    setTitle("MyTitle");
    bf.setChangeListener(this);
    add(bf);

}

public void fieldChanged(Field field, int context) {
    // TODO Auto-generated method stub
    if(field == bf)
    {
        add(lbl);
    }
}
}

Answer 2

In field-changed listener, replace this code

 public void fieldChanged(Field field, int context) {
        System.out.println("hi.. now you can try with text field");
 }

with

public void fieldChanged(Field field, int context) {
    if(field == mySubmitButton) {
        System.out.println("hi.. now you can try with text field");
    }      
}

Don't write just what you want to do. First check if it is a ButtonField then write code for it.

Answer 3

Try this:

buttons.setChangeListener(new FieldChangeListener()
    {

        public void fieldChanged(Field field, int context)
        {
            System.out.println("hi.. now you can try with text field");
            Dialog.alert("hi.. now you can try with text field");

        }
    });