Custom button field blackberry: onfocus, onUnfocus - button

Question

I want to change the colors of background button and the color of text onfocus
How can I make it?
class RoundedRectField extends Field {
// Layout values
private static final int CURVE_X = 12; // X-axis inset of curve
private static final int CURVE_Y = 12; // Y-axis inset of curve
private static final int MARGIN = 2; // Space within component boundary
// Static colors
private static final int TEXT_COLOR = 0xFFFFFF; // White
private static final int BORDER_COLOR = 0xFF8000; // dark gray
private static final int BACKGROUND_COLOR = 0xFFFFFF; // White
private static final int TEXT_COLOR_selected = 0xFF6DB6;
private static final int BORDER_COLOR_selected = 0xFF8000;
private static final int BACKGROUND_COLOR_selected = 0xCCCCCC;
boolean _focus = false;
private static String text_button;
// Point types array for rounded rectangle. Each point type
// corresponds to one of the colors in the colors array. The
// space marks the division between points on the top half of
// the rectangle and those on the bottom.
private static final byte[] PATH_POINT_TYPES = {
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT, Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT, Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT, };
// Colors array for rounded rectangle gradient. Each color corresponds
// to one of the points in the point types array. Top light, bottom black.
private static final int[] PATH_GRADIENT = { 0xFF8000, 0xFF8000, 0xFF8000,
0xFF8000, 0xFF8000, 0xFF8000,
0xFC0500, 0xFC0500, 0xFC0500, 0xFC0500, 0xFC0500, 0xFC0500 };
// Center our readonly field in the space we're given.
public RoundedRectField(String text_button) {
super(FIELD_HCENTER | FIELD_VCENTER | READONLY);
this.text_button = text_button;
}
// This field in this demo has a fixed height.
public int getPreferredHeight() {
return 70;
}
// This field in this demo has a fixed width.
public int getPreferredWidth() {
return 240;
}
// When layout is requested, return our height and width.
protected void layout(int width, int height) {
setExtent(getPreferredWidth(), getPreferredHeight());
}
// When painting is requested, do it ourselves.
protected void paint(Graphics g) {
// Clear this area to white background, fully opaque.
g.clear();
g.setGlobalAlpha(255);
g.setBackgroundColor(BACKGROUND_COLOR);
// Drawing within our margin.
int width = getPreferredWidth() - (MARGIN * 2);
int height = getPreferredHeight() - (MARGIN * 2);
// Compute paths for the rounded rectangle. The 1st point (0) is on
// the left
// side, right where the curve in the top left corner starts. So the
// top left
// corner is point 1. These points correspond to our static arrays.
int[] xPts = { 0, 0, CURVE_X, width - CURVE_X, width, width, width,
width, width - CURVE_X, CURVE_X, 0, 0 };
int[] yPts = { CURVE_Y, 0, 0, 0, 0, CURVE_Y, height - CURVE_Y,
height, height, height, height, height - CURVE_Y };
// Draw the gradient fill.
g.drawShadedFilledPath(xPts, yPts, PATH_POINT_TYPES, PATH_GRADIENT,
null);
// Draw a rounded rectangle for the outline.
// I think that drawRoundRect looks better than drawPathOutline.
g.setColor(BORDER_COLOR);
g.drawRoundRect(0, 0, width, height, CURVE_X * 2, CURVE_Y * 2);
// Place some text in the center.
Font font = Font.getDefault().derive(Font.PLAIN, 9, Ui.UNITS_pt);
int textWidth = font.getAdvance(text_button);
int textHeight = font.getHeight();
g.setColor(TEXT_COLOR);
g.setFont(font);
g.drawText(text_button, (width / 2) - (textWidth / 2) - MARGIN,
(height / 2) - (textHeight / 2) - MARGIN);
}
protected void onFocus(int direction) {
_focus = true;
Dialog.alert("dcd");
invalidate();
super.onFocus(direction);
}
protected void onUnfocus() {
_focus = false;
invalidate();
super.onUnfocus();
}
}

Answer 1

You can do it several ways. One popular way is to provide custom focus drawing in the paint() method, which you already override.
You should be able to do this (I'm assuming you declared the _selected colors for the focused state):
if (isFocus()) {
g.setBackgroundColor(BACKGROUND_COLOR_selected);
else {
g.setBackgroundColor(BACKGROUND_COLOR);
}
...
if (isFocus()) {
g.setColor(TEXT_COLOR_selected);
} else {
g.setColor(TEXT_COLOR);
}
Those lines go in paint(), right where you are currently calling g.setBackgroundColor and g.setColor(TEXT_COLOR).
Then, you would override drawFocus() and do nothing, since your focus drawing is handled in paint():
protected void drawFocus(Graphics graphics, boolean on) {
// override superclass implementation and do nothing
}
Finally, you need to make your Field focusable, in order to ever receive focus. You can do so like this:
public RoundedRectField(String text_button) {
super(FIELD_HCENTER | FIELD_VCENTER | FOCUSABLE);
this.text_button = text_button;
}
If you need the field to be dynamically focusable (sometimes focusable, or sometimes not focusable), then you could implement this method:
public boolean isFocusable() {
But, if the field is always focusable, then using the FOCUSABLE flag in your constructor will work. I tested this out, and I saw the text color change with focus (on a OS 5.0 9550).