黑莓：如果另一个字段绘制到相同的 x 坐标，则获得字段焦点时出现问题

Question

我有一个 AbsoluteFieldManager，其中包含水平行中的多个字段，切换焦点效果很好。现在我需要在与上面左侧字段相同的水平位置上添加另一个字段。这样做时，我无法再专注于第一个字段。屏幕应如下所示：

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

如果您有任何解决此问题的想法，我将不胜感激。这是到目前为止我的代码：

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

由于 AbsoluteFieldManager 不确定您将项目放置在哪里，因此它不知道使用拨轮时发送焦点的顺序。如果您想对此进行管理，请调用 AFM 的 nextFocus(int, int) ，以便您可以根据焦点位置和预期移动位置来指定谁获得焦点。

看一下 http://www.blackberry.com/developers/docs/5.0.0api/net/rim/device/api/ui/Manager.html#nextFocus(int,%20int) 了解更多详细信息。