Adding background image to blackberry app not working - blackberry

Question

i am new to blackberry development and want to add an image to a sample blackberry application. I have tried multiple tutorials, but the image is not displaying in the background
can any one kindly tell me what is the problem?
/**
* This class extends the UiApplication class, providing a graphical user
* interface.
*/
public class Diverse extends UiApplication {
private Bitmap backgroundBitmap;
private Bitmap fieldBitmap;
public static void main(String[] args) {
Diverse diverse = new Diverse();
diverse.enterEventDispatcher();
}
/**
* Creates a new MyApp object
*/
public Diverse() {
//The background image.
backgroundBitmap = Bitmap.getBitmapResource("background.png");
MainScreen mainScreen = new MainScreen();
HorizontalFieldManager horizontalFieldManager = new HorizontalFieldManager(HorizontalFieldManager.USE_ALL_WIDTH | HorizontalFieldManager.USE_ALL_HEIGHT){
//Override the paint method to draw the background image.
public void paint(Graphics graphics)
{
//Draw the background image and then call paint.
graphics.drawBitmap(0, 0, 240, 240, backgroundBitmap, 0, 0);
super.paint(graphics);
}
};
//The LabelField will show up through the transparent image.
LabelField labelField = new LabelField("This is a label");
//A bitmap field with a transparent image.
//The background image will show up through the transparent BitMapField image.
BitmapField bitmapField = new BitmapField(Bitmap.getBitmapResource("field.png"));
//Add the manager to the screen.
mainScreen.add(horizontalFieldManager);
//Add the fields to the manager.
horizontalFieldManager.add(labelField);
horizontalFieldManager.add(bitmapField);
// Push a screen onto the UI stack for rendering.
pushScreen(new DiverseScreen());
}
}
and DiverseScreen class is
package diverse;
import net.rim.device.api.ui.container.MainScreen;
/**
* A class extending the MainScreen class, which provides default standard
* behavior for BlackBerry GUI applications.
*/
public final class DiverseScreen extends MainScreen
{
/**
* Creates a new MyScreen object
*/
public DiverseScreen()
{
// Set the displayed title of the screen
setTitle("Diverse");
}
}

Answer 1

The problem is that you have set the background image for one screen, but you never displayed that screen. Then, you displayed a different screen that did not have a background image set.
First, it helps to understand the BlackBerry UI framework. It allows you to create a hierarchy of objects on screen. At the top level, you have a Screen (or subclass of Screen), and then inside of the Screen, you have Managers, and inside them are Fields. But, each level must be added to a container of some kind, and finally, the top-level Screen must be displayed with something like pushScreen().
See a little more description on this hierarchy in a recent answer here
In your situation, you should change this line
MainScreen mainScreen = new MainScreen();
to
DiverseScreen mainScreen = new DiverseScreen();
and then change this line
pushScreen(new DiverseScreen());
to
pushScreen(mainScreen);
since mainScreen is the instance where you added a horizontal field manager that draws your background image.