Question

此问题仅涉及代号One。

用例

像Instagram这样的几个应用程序都有x轴可滚动框，如以下视频所示：

https://www.informatica-libera.net/videoLavoro/Video-2019-02-07-11-16-59_0569.mp4

实现起来似乎很容易（将BoxLayout.x()设置为在x轴上可滚动），但这并不是那么容易。有一个隐藏的复杂性：每个框的宽度以屏幕宽度的百分比表示，因为用户应该看到第一个框和一小块第二个框，以了解可以滚动。也许这在Instagram应用程序中还不够清楚，但在其他应用程序中更明显。

我做了什么

我无法弄清楚如何嵌套Codename One布局来满足x可滚动BoxLayout.x的要求，其中每个Component都应占据屏幕宽度的60％。但是，我设法通过自定义Layout得到了非常相似的东西，但是有一个大问题：我没有找到一种根据盒子内容自动计算盒子高度的方法。目前，我有一个百分比宽度和一个固定的高度。请在模拟器中观看此视频：

https://www.informatica-libera.net/videoLavoro/Video-2019-02-07-11-38-10_0570.mp4

我的方法的另一个问题是我的代码不适用于SpanLabel（我将文本拆分为标记，并为每个标记创建了Label）。

我的代码

以下代码是测试用例，可以轻松复制和运行。请注意，实际问题是根据用户数据生成的，因此我事先不知道问题的长度。此外，平板电脑的屏幕宽度与智能手机的屏幕宽度不同（因此这两种情况下的高度应不同）。此刻，我将固定高度设置为20mm。

TestBoxes.java

import static com.codename1.ui.CN.*;
import com.codename1.ui.Form;
import com.codename1.ui.Dialog;
import com.codename1.ui.Label;
import com.codename1.ui.plaf.UIManager;
import com.codename1.ui.util.Resources;
import com.codename1.io.Log;
import com.codename1.ui.Button;
import com.codename1.ui.Component;
import com.codename1.ui.Container;
import com.codename1.ui.Display;
import com.codename1.ui.Toolbar;
import com.codename1.ui.geom.Dimension;
import com.codename1.ui.layouts.BoxLayout;
import com.codename1.ui.layouts.FlowLayout;
import com.codename1.ui.layouts.Layout;
import com.codename1.util.StringUtil;
import java.util.LinkedHashMap;
import java.util.List;

/**
 * This file was generated by <a href="https://www.codenameone.com/">Codename
 * One</a> for the purpose of building native mobile applications using Java.
 */
public class TestBoxes {

    private Form current;
    private Resources theme;

    public void init(Object context) {
        // use two network threads instead of one
        updateNetworkThreadCount(2);

        theme = UIManager.initFirstTheme("/theme");

        // Enable Toolbar on all Forms by default
        Toolbar.setGlobalToolbar(true);

        // Pro only feature
        Log.bindCrashProtection(true);

        addNetworkErrorListener(err -> {
            // prevent the event from propagating
            err.consume();
            if (err.getError() != null) {
                Log.e(err.getError());
            }
            Log.sendLogAsync();
            Dialog.show("Connection Error", "There was a networking error in the connection to " + err.getConnectionRequest().getUrl(), "OK", null);
        });
    }

    public void start() {
        if (current != null) {
            current.show();
            return;
        }
        Form hi = new Form("Test Boxes", BoxLayout.y());
        hi.add(getCompleteProfileCnt());
        hi.show();
    }

    public void stop() {
        current = getCurrentForm();
        if (current instanceof Dialog) {
            ((Dialog) current).dispose();
            current = getCurrentForm();
        }
    }

    public void destroy() {
    }

    public Container getCompleteProfileCnt() {
        LinkedHashMap<String, Form> questions = new LinkedHashMap<>(6);
        int count = getRemainingQuestions(questions);
        Label completeProfileLabel = new Label("Complete your profile");

        Container boxQuestions = new Container(new BoxLayout(BoxLayout.X_AXIS_NO_GROW));
        boxQuestions.setScrollableX(true);

        for (String question : questions.keySet()) {
            Button button = new Button("Complete");
            if (questions.get(question) != null) {
                button.addActionListener(l -> {
                    questions.get(question).show();
                });
            } else {
                button.addActionListener(l -> {
                    Log.p("To be implemented...");
                });
            }
            Container boxSingleQuestion = new Container(new FixedBoxLayout(60, 20), "ProfileUtilities-BoxSingleQuestion");
            Container questionCnt = FlowLayout.encloseCenter(getArrayLabels(question, "Label"));
            Container singleQuestionCnt = BoxLayout.encloseYBottomLast(questionCnt, FlowLayout.encloseCenter(button));
            questionCnt.setUIID("ProfileUtilities-QuestionCnt");
            singleQuestionCnt.setUIID("ProfileUtilities-SingleQuestionCnt");
            boxSingleQuestion.add(singleQuestionCnt);
            boxQuestions.add(boxSingleQuestion);
        }

        Container resultCnt = new Container(BoxLayout.y());
        resultCnt.add(completeProfileLabel);
        resultCnt.add(boxQuestions);
        return resultCnt;

    }

    /**
     * Inserts in the given "questions" Map the remaining questions to complete
     * the profile of the current logged user, and returns the number of all
     * questions (that can be >= to the remaining questions);
     *
     * @param questions, note that the Map will be cleared before adding the
     * remaining questions
     *
     * @return
     */
    private int getRemainingQuestions(LinkedHashMap<String, Form> questions) {
        // THIS METHOD IS AN EXAMPLE, the questions are generated according to the user data
        int countTotalQuestions = 3;
        if (questions == null) {
            throw new IllegalArgumentException("ProfileUtilities.getRemainingQuestions invalid \"questions\" param, because it's null");
        }
        questions.clear();

        questions.put("Question 1 - Suppose that this a long text, try to make it longer", null);
        questions.put("Question 2 - Suppose a short text", null);
        questions.put("Question 3 - Suppose a short text plus an icon", null);

        return countTotalQuestions;
    }

    public static List<String> tokenize(String text, String separator) {
        if (separator == null) {
            separator = "\n";
        }
        return StringUtil.tokenize(text, separator);
    }

    /**
     * Converts a string to an array of Labels, that can be placed in a
     * FlowLayout: conceptually similar to RichTextView, it serves for special
     * use cases (like custom layouts) where a SpanLabel doesn't work well.
     *
     * @param text
     * @param UIID for font style, note that margin and padding will be ignored
     * @return
     */
    public static Label[] getArrayLabels(String text, String UIID) {
        List words = tokenize(UIManager.getInstance().localize(text, text), " ");
        Label[] labels = new Label[words.size()];
        for (int i = 0; i < words.size(); i++) {
            labels[i] = new Label(words.get(i) + " ", UIID);
            labels[i].getAllStyles().setMargin(0, 0, 0, 0);
            labels[i].getAllStyles().setPadding(0, 0, 0, 0);
        }
        return labels;
    }

    class FixedBoxLayout extends Layout {

        private int preferredWidth;
        private final int preferredHeight;
        private boolean isListenerAdded = false;
        private int percentageWidth;

        public FixedBoxLayout(int percentageWidth, float heightMM) {
            preferredWidth = Display.getInstance().getDisplayWidth() * percentageWidth / 100;
            preferredHeight = Display.getInstance().convertToPixels(heightMM);
            this.percentageWidth = percentageWidth;
        }

        @Override
        public void layoutContainer(Container parent) {
            Component cmp = parent.getComponentAt(0);
            cmp.setWidth(preferredWidth);
            cmp.setPreferredW(preferredWidth);
            cmp.setHeight(preferredHeight);
            cmp.setPreferredH(preferredHeight);
            if (cmp instanceof Container) {
                for (Component inner : ((Container) cmp).getChildrenAsList(true)) {
                    inner.setWidth(preferredWidth);
                    inner.setPreferredW(preferredWidth);
                }
            }
            if (!isListenerAdded) {
                isListenerAdded = true;
                parent.getComponentForm().addSizeChangedListener(l -> {
                    preferredWidth = Display.getInstance().getDisplayWidth() * percentageWidth / 100;
                    parent.revalidate();
                });
            }
        }

        @Override
        public Dimension getPreferredSize(Container parent) {
            return new Dimension(preferredWidth, preferredHeight);
        }

    }
}

theme.css

#Constants {
    includeNativeBool: true; 
}

/* Default text and color */
Default, Label, TextArea, TextField {
    font-family: "native:MainRegular";
    font-size: 3mm;
    color: black;
}
Button {
    font-family: "native:MainRegular";
    font-size: 3mm;
    color: white;
    background-color: black;
    border: 0.2mm black cn1-pill-border;
    padding: 0.5mm 1mm 0.5mm 1mm; /* top, right, bottom, left */
    margin: 1mm;
}

Button.pressed, Button.selected {
    color: black;
    background-color: white;
}

Button.disabled {
    color: white;
    background-color: gray;
}

ProfileUtilities-completeProfileLabel {
    font-family: "native:MainBold";
    font-size: 3.5mm;
    color: black;
    margin: 1mm;
    padding: 0;
    margin-bottom: 0;
}

ProfileUtilities-completeProfileBox {
    margin: 0;
    margin-top: 1mm;
    margin-bottom: 1mm;
    border: 1pt #3399ff solid;
    border-radius: 2mm;
}

ProfileUtilities-CompletedQuestions {
    font-family: "native:MainRegular";
    font-size: 3mm;
    color: darkgoldenrod;
    margin: 1mm;
    margin-top: 0;
    padding: 0;
}

ProfileUtilities-SingleQuestionLabel {
    font-family: "native:MainBold";
    font-size: 3mm;
    color: darkslateblue;
    text-align: center;
    padding: 2mm;
}

ProfileUtilities-BoxSingleQuestion {
    border: 1pt darkmagenta solid;
    border-radius: 2mm;
    /* This is the margin between boxes */
    margin: 1mm;
}

ProfileUtilities-SingleQuestionCnt {
    /* This is the padding inside each box */
    padding: 0;
    padding-top: 1mm;
    padding-bottom: 1mm;
}

ProfileUtilities-QuestionCnt {
    /* This is the padding of each question text */
    padding: 2mm;
}

此测试用例的屏幕截图：

我的问题

我需要一个适合此用例的代码，以改进现有代码（如果我的代码有太多错误，请编写新代码）。谢谢

Answer 1

编辑，这仍然需要对您的需求进行一些调整，但这是我所做更改的要旨：

        Container boxSingleQuestion = new Container(BoxLayout.y(), "ProfileUtilities-BoxSingleQuestion");
        Container questionCnt = new Container(new FlowLayout(CENTER)) {
            @Override
            protected Dimension calcPreferredSize() {
                Dimension d = super.calcPreferredSize(); 
                d.setWidth(Math.min(getDisplayWidth(), getDisplayHeight()) / 10 * 6);
                d.setHeight(d.getHeight() / 10 * 18);
                return d;
            }                
        };
        questionCnt.addAll(getArrayLabels(question, "Label"));
        Container singleQuestionCnt = BorderLayout.center(questionCnt).
                add(SOUTH, FlowLayout.encloseCenter(button));
        questionCnt.setUIID("ProfileUtilities-QuestionCnt");
        singleQuestionCnt.setUIID("ProfileUtilities-SingleQuestionCnt");
        boxSingleQuestion.add(singleQuestionCnt);
        boxQuestions.add(boxSingleQuestion);

我删除了YLast布局的特殊布局和使用方式，该布局是专为全屏设计的，在这种情况下可能无法正常工作。通常，我所做的是减小首选宽度，然后将首选高度增加一个固定值。通过使用BorderLayout，底部的按钮将始终可见。

下面的原始答案：

您正在从布局中更改组件的首选高度/宽度。错了，你永远都不要这样做。布局应仅设置宽度/高度。如果设置宽度，则可以使用首选高度来获得正确的高度。要确保所有组件的高度相同，只需在组件上循环：

int height = 0;
for(Component c : parent) {
    height = Math.max(height, c.getPreferredH());
}

假设您已修复代码以不更改首选宽度或高度（宽度也会影响高度！），这应该会给您带来身高。

一种稍微简单的方法是使用BoxLayout.X并为您的组件覆盖calcPreferredSize（）以返回等于屏幕尺寸60％的值。

代号一种具有百分比宽度和自适应高度的自定义布局

1 个答案: