How to change the font color of blackberry label field dynamically?

Question

I have one label field and three buttons with the name of red, yellow, blue. If I click the red button then the label field font color should be change to red; similarly if I click the yellow button then the font color should change to yellow; likewise according to the button color the color of font should change in the label field.

Can anyone tell me how to do this?

Answer 1

Font color in LabelField is easily maintained by setting graphics.setColor on paint event before super.paint:

    class FCLabelField extends LabelField {
        public FCLabelField(Object text, long style) {
            super(text, style);
        }

        private int mFontColor = -1;

        public void setFontColor(int fontColor) {
            mFontColor = fontColor;
        }

        protected void paint(Graphics graphics) {
            if (-1 != mFontColor)
                graphics.setColor(mFontColor);
            super.paint(graphics);
        }
    }

    class Scr extends MainScreen implements FieldChangeListener {
        FCLabelField mLabel;
        ButtonField mRedButton;
        ButtonField mGreenButton;
        ButtonField mBlueButton;

        public Scr() {
            mLabel = new FCLabelField("COLOR LABEL", 
                    FIELD_HCENTER);
            add(mLabel);
            mRedButton = new ButtonField("RED", 
                    ButtonField.CONSUME_CLICK|FIELD_HCENTER);
            mRedButton.setChangeListener(this);
            add(mRedButton);
            mGreenButton = new ButtonField("GREEN", 
                    ButtonField.CONSUME_CLICK|FIELD_HCENTER);
            mGreenButton.setChangeListener(this);
            add(mGreenButton);
            mBlueButton = new ButtonField("BLUE", 
                    ButtonField.CONSUME_CLICK|FIELD_HCENTER);
            mBlueButton.setChangeListener(this);
            add(mBlueButton);
        }

        public void fieldChanged(Field field, int context) {
            if (field == mRedButton) {
                mLabel.setFontColor(Color.RED);
            } else if (field == mGreenButton) {
                mLabel.setFontColor(Color.GREEN);
            } else if (field == mBlueButton) {
                mLabel.setFontColor(Color.BLUE);
            }
            invalidate();
        }
    }