如果isSelected，如何在ListCellRenderer中为Component使用主题Selected样式

Question

我有一个自定义 ListCellRenderer，我希望在其中用背景渐变突出显示当前选定的项目。

看来我应该能够在主题下的 Codenameone Designer 中为呈现的组件定义 Selected 样式，并为组件设置该 UIID 以实现此目的。

我不知道如何将列表项的选定状态传递给正在呈现的 Label 组件，所以我求助于手动更改样式，如您在下面的代码中所见。我可以用我的主题 Resources 以某种方式完成相同的行为吗？

public class PlanetListRenderer extends Container implements ListCellRenderer<Hashtable<String, String>> {
    private Label planetLabel = new Label();
    private Resources theme;

    public PlanetListRenderer(Resources theme) {
        this.theme = theme;
        BoxLayout bl = new BoxLayout(BoxLayout.Y_AXIS);
        setLayout(bl);

        planetLabel.setUIID("PlanetListItem");
        planetLabel.setTextPosition(Label.BOTTOM);
        addComponent(planetLabel);
    }

    public Component getListFocusComponent(List list) {
        return planetLabel;
    }
    public Component getListCellRendererComponent(List list,
            Hashtable<String, String> value, int index, boolean isSelected) {

        planetLabel.setIcon(theme.getImage("icon" + value.get("value") + ".png"));
        planetLabel.setText(value.get("value"));

        if ( isSelected ) {
            planetLabel.getStyle().setBackgroundGradientStartColor(255255255);
            planetLabel.getStyle().setBackgroundGradientRelativeY(0.2f);
            planetLabel.getStyle().setBackgroundGradientRelativeSize(1.0f);
            planetLabel.getStyle().setBackgroundType(Style.BACKGROUND_GRADIENT_RADIAL);
        } else {
            planetLabel.getStyle().setBackgroundType(Style.BACKGROUND_NONE);
        }

        return this;
    }
}

Answer 1

我建议使用背景 images/borders 而不是性能不佳的渐变。

默认情况下，触摸 UI 不会永久显示选择。如果您使用 getAllStyles 而不是 getStyle 例如：

Form hi = new Form("Renderer Demo", new BorderLayout());
ArrayList<Map<String, String>> al = new ArrayList<>();
for(int iter = 0 ; iter < 100 ; iter++) {
    HashMap<String, String> data = new HashMap<String, String>();
    data.put("key1", "Data " + iter);
    data.put("key2", "Different Data " + iter);
    al.add(data);
}
DefaultListModel<Map<String, String>> listModel = new DefaultListModel<>(al);
List<Map<String, String>> l = new List<>(listModel);
l.setRenderer(new ListCellRenderer() {
    private Container           container;
    private Label                   cover;
    private TextArea             item;

    {
        item = new TextArea(2, 80);
        cover = new Label();
        container = BorderLayout.center(item).add(BorderLayout.EAST, cover);
        container.setCellRenderer(true);
        cover.setCellRenderer(true);
        item.setCellRenderer(true);
    }

    @Override
    public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {
        Map<String, String> val = (Map<String, String>)value;
        item.setText(val.get("key1"));
        cover.setText(val.get("key2"));

        Style itemStyle = item.getAllStyles();
        Style coverStyle = cover.getAllStyles();
        Style containerStyle = container.getAllStyles();

        itemStyle.setBgTransparency(255);
        coverStyle.setBgTransparency(255);
        containerStyle.setBgTransparency(255);

        if (isSelected) {
            itemStyle.setFgColor(0xff0000);
            itemStyle.setBgColor(0x000000);
            coverStyle.setBgColor(0xff0000);
            containerStyle.setBgColor(0x000000);
        } else {
            itemStyle.setFgColor(0x000000);
            itemStyle.setBgColor(0xffffff);
            coverStyle.setBgColor(0x000000);
            containerStyle.setBgColor(0xffffff);
        }

        return container;
    }

    @Override
    public Component getListFocusComponent(List list) {
        return null;
    }
});
hi.add(BorderLayout.CENTER, l);
hi.show();

Answer 2

下面是一个 ListCellRenderer，它改变了 selected 项目。不确定它是否满足您的需求，但您可以通过搜索 "Torquepower Diesel Cummins Engine" 应用程序从 Google Play（或 App Store）中看到真实的效果。当您 select 任何列表项时，您会看到背景发生变化。

public class FaultCodesListCellRenderer extends Container implements ListCellRenderer {

Label focus;
Label code;
Label effect;
Image warning;
Image emergency;

public FaultCodesListCellRenderer(Resources res) {

    // get images for warning lights
    emergency = res.getImage("emergency.png");
    warning = res.getImage("warning.png");

    setLayout(new BorderLayout());
    setUIID("Underline");

    code = new Label();
    code.setUIID("BoldLabel");
    code.setTextPosition(RIGHT);
    code.getStyle().setMargin(Component.RIGHT, 6);

    effect = new Label();
    effect.setTickerEnabled(false);

    addComponent(BorderLayout.WEST, code);
    addComponent(BorderLayout.CENTER, effect);

    int h = Display.getInstance().convertToPixels(8, false);
    setPreferredH(code.getPreferredH() < h ? h : code.getPreferredH());

    focus = new Label("");
    focus.setUIID("UnderlineSelected");

}

public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {

    Diagnostic diagnostic = (Diagnostic) value;

    if (diagnostic.light.equals("R")) {
        code.setIcon(emergency);
    } else {
        code.setIcon(warning);
    }
    code.setText(diagnostic.code);
    effect.setText(diagnostic.effect);

    return this;
}

public Component getListFocusComponent(List list) {
    return focus;
}

如果isSelected，如何在ListCellRenderer中为Component使用主题Selected样式

How to use theme Selected style for Component in ListCellRenderer if isSelected

java

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