Question

I have an AbsoluteFieldManager that contains several Fields in a horizontal row, switching the focus works fine. Now i need to add another Field on the same horizontal position as the left field above. When doing so, I can no more focus the first field. The screen should look as this:

________________________
|  ____   ____   ____  |
| |_f1_| |_f2_| |_f3_| |
|  ____                |
| |_f4_|               | with f4 added here, f1 isn't focusable, once it has
|______________________| lost focus.

If you got any Ideas how to fix this, I’d apreciate. Here is my Code so far:

TestScreen:

import net.rim.device.api.system.Display;
import net.rim.device.api.ui.container.AbsoluteFieldManager;
import net.rim.device.api.ui.container.MainScreen;

public class TestScreen extends MainScreen {
    int screenY = Display.getWidth();
    int screenX = Display.getHeight();

    public TestScreen() {
        AbsoluteFieldManager manager = new AbsoluteFieldManager();
        TestField f1 = new TestField(50, 50, true);
        TestField f2 = new TestField(50, 50, true);
        TestField f3 = new TestField(50, 50, true);
        TestField f4 = new TestField(50, 50, true);
        TestField f5 = new TestField(50, 50, false);
        manager.add(f1, 0, 0);
        manager.add(f2, 60, 0);
        manager.add(f3, 120, 0);
        manager.add(f4, 180, 0);
        // this works fine: 
        // manager.add(f5, 1, 80);
        // this not:
        manager.add(f5, 0, 80);
        add(manager);
    }
}

TestField:

import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;


public class TestField extends Field {
    boolean isFocusable;
    int width, height;
    int bgColorUnfocused, bgColorFocused;
    public TestField(int width, int height, boolean isFocusable){
        this.width=width;
        this.height=height;
        this.isFocusable=isFocusable;
        bgColorUnfocused= 0xC0C0C0;
        bgColorFocused = 0x3956F7;
    }
    protected void layout(int w, int h) {
        setExtent(width, height);
    }
    public boolean isFocusable() {
        return isFocusable;
    }
    protected void paint(Graphics g) {
        g.setColor(isFocus() ? bgColorFocused : bgColorUnfocused);
        g.fillRect(0, 0, width, height);        
    }

}

TestApp:

import net.rim.device.api.ui.UiApplication;


public class TestApp extends UiApplication{
    TestScreen screen = new TestScreen();
    public static void main(String args[]){
        TestApp app = new TestApp();
        app.enterEventDispatcher();
    }
    public TestApp(){
        pushScreen(screen);
    }
}

Answer 1

Since AbsoluteFieldManager isn’t really sure where you’re placing items, it doesn’t know what order to send focus when using the trackwheel. If you want to manage this, ovveride nextFocus(int, int) of the AFM so you can specify who gets the focus based off of where it is and where the intended movement is.

Take a look at http://www.blackberry.com/developers/docs/5.0.0api/net/rim/device/api/ui/Manager.html#nextFocus(int,%20int) for more details.