黑莓定制Horizo​​ntalFieldManager

Question

在 Blackberry 中，我想创建一个扩展 Horizo​​ntalFieldManager 的类，以便我可以在同一行上显示标签和图像，标签在左侧，图像在右侧。
我希望用户能够与 Horizo​​ntalFieldManager 交互，就好像它是单个字段一样。我还希望每个 Horizo​​ntalFieldManager 在添加到 VerticalFieldManager 时都可以聚焦。我还想要 clik 动作事件。

Answer 1

听起来您想要开始编写自己的 Field 类，下面是一个帮助您入门的示例：

import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;

public class SimpleField extends Field {

    private String label;
    private Bitmap image;
    private int fieldWidth;
    private int fieldHeight;
    private boolean hover = false;
    private int focusColor = 0xcccccc;

    public SimpleField(String label, Bitmap image) {
        super(Field.FOCUSABLE);
        this.label = label;
        this.image = image;
        fieldWidth = Display.getWidth();
        fieldHeight = image.getHeight();
    }

    protected void onFocus(int direction) {
        hover = true;
        invalidate();
        super.onFocus(direction);
    }

    protected void onUnfocus() {
        hover = false;
        invalidate();
        super.onUnfocus();
    }

    public int getPreferredWidth() {
        return fieldWidth;
    }

    public int getPreferredHeight() {
        return fieldHeight;
    }

    protected void layout(int width, int height) {
        setExtent(fieldWidth, fieldHeight);
    }

    protected void paint(Graphics graphics) {
        if(hover){
            graphics.setColor(focusColor);
            graphics.fillRect(0, 0, fieldWidth, fieldHeight);
        }
        graphics.drawText(label, 0, (fieldHeight - graphics.getFont().getHeight()) / 2);
        graphics.drawBitmap(graphics.getFont().getAdvance(label), 0, image.getWidth(), image.getHeight(), image, 0, 0);
    }
}