它展示了什么
A real map with pins on it, and the two things that make a map different from every other widget.
It is a native view on top of the GL canvas, not a component inside it. It does not scroll with a parent, does not clip to one, and does not take part in a screen transition — a fade over a map shows a black rectangle for the whole animation. So a map gets a rectangle of its own and every control you want over it goes outside that rectangle, in ordinary components.
The engine is a constructor argument. Changing provider means building a new
MapContainer — there is no setter, and there should not be one. OSM needs no key
and is the right default for anything that is not shipping; GOOGLE needs
MapContainer.googleMapsKey set before the container is built.
Opened on a button rather than built into this screen, on purpose: a native view inside a scrolling recipe list would float over the recipes above and below it.
在你的机器上运行
每个示例都是普通的 Window,启动器只需要它的名字。
gradlew lwjgl3:run --args="classname dev.cf.recipe.R25Map"Java 是提前编译的,浏览器无法自行重建你的修改 —— 这里的代码在发布前已由 TeaVM 转成 JavaScript。把文件复制到项目里,它在四个平台上原样运行;上面那条命令就是全部准备工作。
它用到了什么
本示例触及的框架类型。带链接的有参考页。
源码
完整无删减。这就是那个文件,不是片段。
package dev.cf.recipe;
import dev.cf.Tones;
import dev.crossfly.map.*;
import dev.crossfly.ui.*;
import dev.crossfly.ui.color.*;
import dev.crossfly.ui.graphics.*;
import dev.crossfly.ui.layout.*;
import dev.crossfly.ui.style.*;
import java.util.ArrayList;
import java.util.List;
import static dev.crossfly.ui.Widgets.*;
/**
* A real map with pins on it, and the two things that make a map different from every other widget.
*
* <p><b>It is a native view on top of the GL canvas</b>, not a component inside it. It does not
* scroll with a parent, does not clip to one, and does not take part in a screen transition — a
* fade over a map shows a black rectangle for the whole animation. So a map gets a rectangle of its
* own and every control you want over it goes <i>outside</i> that rectangle, in ordinary
* components.</p>
*
* <p><b>The engine is a constructor argument.</b> Changing provider means building a new
* {@link MapContainer} — there is no setter, and there should not be one. {@code OSM} needs no key
* and is the right default for anything that is not shipping; {@code GOOGLE} needs
* {@code MapContainer.googleMapsKey} set before the container is built.</p>
*
* <p>Opened on a button rather than built into this screen, on purpose: a native view inside a
* scrolling recipe list would float over the recipes above and below it.</p>
*/
public class R25Map extends Recipe
{
/** A few coordinates to plot. Real ones come from your store — with the nulls filtered out. */
private static final double[][] WHERE = { { 53.7996, -1.5491 }, { 51.2194, 4.4025 },
{ 41.1579, -8.6291 }, { 45.0703, 7.6869 }, { 55.6050, 13.0038 }, { 51.4545, -2.5879 } };
private static final String[] WHO = { "Northgate", "Bellamy", "Kestrel", "Halden & Roe",
"Ironvale", "Meridian" };
public String title()
{
return "A map with pins";
}
public String note()
{
return "OSM needs no API key, so a map works the moment you write it. Opens in a window of"
+ " its own — a native view inside a scrolling page floats over everything around it.";
}
public void build(Component body) throws Exception
{
body.add(LAY_AUTO, outgap(label("Six suppliers, plotted from coordinates. The pins are data;"
+ " the map only draws them.", 1f, false, Styles.captionColor, Position.START), 0, 0, 0,
1f));
Button open = Tones.action("Open the map");
open.testTag("map.open");
open.onAction(c -> new MapScreen().show());
body.add(LAY_AUTO, open);
}
/** The map, in a window of its own, with the app's chrome kept outside its rectangle. */
private static class MapScreen extends Window
{
private MapContainer container;
@Override
public void onAdd(boolean firstTime) throws Exception
{
if (!firstTime)
return;
fullscreenColor = Styles.backColor.color();
setLayout(new VerticalLayout(Position.START, Position.START));
Component bar = new Component();
bar.setLayout(new GridLayout(Position.START, Position.CENTER));
bar.getStyle()
.ingap(Gap.ofFont(.6f, .5f, .6f, .5f));
Button back = new Button(MaterialIcon.of(0xE5C4, 1.4f));
back.onAction(c -> hide());
bar.add(0f, 1f, back, outgap(label("Suppliers", 1.5f, true, Styles.textColor,
Position.START), .6f, 0, 0, 0));
add(0f, bar);
// OSM: no key, no account, works offline against its own tiles cache. The callback fires
// when the native view is ready — plotting before that plots into nothing.
container = new MapContainer(Map.MapEngine.OSM, 0, this::plot);
add(LAY_FILL, container);
}
private void plot()
{
try
{
final List<MapPin> pins = new ArrayList<>();
double lat = 0, lon = 0;
for (int i = 0; i < WHERE.length; i++)
{
pins.add(new MapPin().position(WHERE[i][0], WHERE[i][1])
.title(WHO[i])
.snippet("Supplier"));
lat += WHERE[i][0];
lon += WHERE[i][1];
}
// batch(): every add is a call across to the native view, and six of them is six
// round-trips and six redraws. Inside a batch it is one. At six pins nobody notices;
// at six hundred it is the difference between a map and a freeze.
container.map.batch(() -> container.map.add(pins.toArray(new MapPin[0])));
// Open on the middle of what was plotted, not on a fixed point: a map that opens
// somewhere the data is not makes the user pan before it tells them anything.
container.map.centerOnLocation(new LatLon(lat / WHERE.length, lon / WHERE.length), 4);
}
catch (Exception e)
{
dev.crossfly.util.Debug.handle(e);
}
}
}
}package dev.cf.recipe;
import dev.cf.*;
import dev.crossfly.ui.*;
import dev.crossfly.ui.graphics.*;
import dev.crossfly.ui.layout.*;
import dev.crossfly.ui.skin.*;
import dev.crossfly.ui.style.*;
import static dev.crossfly.ui.Widgets.*;
/**
* Base of a <b>recipe</b>: one screen that shows one thing, and nothing else.
*
* <p>A recipe is not a sample. A sample shows a component with all its knobs; a recipe answers a
* question somebody actually has — "how do I put a filter sheet over a list?", "how do I make this
* follow the theme?" — in as few lines as it takes, so the answer can be read in one screen and
* copied without editing.</p>
*
* <p>That is the whole design constraint: <b>the boilerplate lives here, the substance lives in the
* subclass.</b> A recipe that spends twenty lines building a title bar teaches the title bar.</p>
*
* <p>Write one as:</p>
*
* <pre>
* public class MyRecipe extends Recipe
* {
* public String title() { return "What this shows"; }
* public String note() { return "The one sentence worth knowing."; }
*
* public void build(Component body) throws Exception
* {
* body.add(LAY_AUTO, new Button("Tap"));
* }
* }
* </pre>
*/
public abstract class Recipe extends SampleWindow implements Described
{
@Override
public abstract String title();
/**
* The one thing a reader should take away — printed above the recipe, in caption tone.
*
* @return the note, or null for none
*/
@Override
public String note()
{
return null;
}
/**
* Builds the recipe.
*
* @param body a vertical, scrollable container with sensible padding — add to it and stop
* @throws Exception when building fails
*/
public abstract void build(Component body) throws Exception;
@Override
public void onAdd(boolean firstTime) throws Exception
{
addTopBar(title());
// The page, not the surface. addTopBar just set fullscreenColor to the surface,
// and on a white page a white card has no edges — see Tones.page(). Re-derived on restyle so
// a dark-mode flip does not leave the light page behind.
fullscreenColor = Tones.page();
onRestyle(() -> fullscreenColor = Tones.page());
contents.setLayout(new VerticalLayout(Position.START, Position.START));
contents.getStyle()
.ingap(Gap.ofFont(1f, 1f, 1f, 1f));
String n = note();
if (n != null)
contents.add(LAY_AUTO, outgap(nota(n), 0, 0, 0, 1f));
Component body = new Component();
body.setLayout(new VerticalLayout(Position.START, Position.START));
body.setScrollable(ScrollDirection.VERTICAL);
body.testTag("recipe.body");
contents.add(LAY_FILL, body);
build(body);
if (pinned != null)
{
// Measured again once its labels have sizes: the band's AUTO height is taken in the first
// layout, before them, and on the iPhone it showed only its first line - the odometer's
// "No text recognizer on this device." was set and never seen (17/10/2026).
final Component band = pinned;
onUI(band::invalidateMeasure);
}
if (pinned != null)
body.add(LAY_AUTO, new Component()
{
@Override
public int getAutoHeight()
{
// Room for the last row to scroll clear of the floating band.
return pinned.getAutoHeight();
}
});
}
/**
* The note, as a tinted band rather than three lines of grey.
*
* <p>It is the one sentence the reader is meant to leave with, and it used to be the least
* legible thing on the screen: caption-coloured, caption-sized, indistinguishable from the
* captions further down that are only labels. A tone and a glyph cost nothing here — nobody has
* to read the band to know what it is.</p>
*
* @param n the note text
* @return the band
* @throws Exception when building fails
*/
/**
* Pins {@code c} to the bottom of the screen, in a band that FLOATS over the scrolling body: it
* stays on screen however far the body is scrolled, and the body scrolls underneath it. That is the
* place a recipe says what just happened. An answer at the top of the body went out of view as soon
* as the person scrolled down to the button that produced it (14/10/2026).
* <p>
* The band is 80% OPAQUE (the surface at alpha 0xCC), as the user asked; it floats rather than
* sitting below the body because a transparency with nothing behind it cannot be seen -- the first
* version had the band under the body, and the person saw a plain bar. The body gets a spacer as
* tall as the band at its end, so its last row can still scroll clear of it.
*
* @param c the component to pin, usually the answer label
* @return {@code c}, to chain
* @throws Exception if the layout refuses
*/
protected <T extends Component> T pin(T c) throws Exception
{
Component band = new Component();
band.setLayout(new VerticalLayout(Position.START, Position.START));
band.style(Skin.get()
.card()
.backColor(Styles.backColor.withAlpha(0xCC))
.borderColor(Styles.borderColor.withAlpha(0x33))
.borderRadius(0)
.shadow(0, 0, 0, 0)
.ingap(Gap.ofFont(1f, 1f, 1f, 1.2f))
.outgap(Gap.ofFont(0)));
band.add(LAY_AUTO, c);
// Floated: positioned at the bottom, full width, over whatever the body has there.
band.setRelativeBounds(Relative.START, Relative.END, Relative.FULL, Relative.AUTO);
contents.add(LAY_AUTO, band);
pinned = band;
return c;
}
/** The floating band {@link #pin} made, or null; the body ends in a spacer as tall as it. */
private Component pinned;
private Component nota(String n) throws Exception
{
Component band = new Component();
band.setLayout(new GridLayout(Position.START, Position.START));
band.style(Skin.get()
.card()
.backColor(Tones.accent().withAlpha(0x16))
.borderColor(Tones.accent().withAlpha(0x4A))
.shadow(0, 0, 0, 0)
.outgap(Gap.ofFont(0)));
// 0xE88E is the outlined "info". The glyph column hugs; the text takes the rest and wraps.
// The weights are GridLayout's own — 0f hugs, 1f takes what is left. LAY_FILL belongs to the
// vertical and horizontal layouts and means nothing here: it collapsed the text to nothing.
band.add(LAY_AUTO, 1f, matglyph(0xE88E, Tones.accent(), 1.05f),
outgap(label(n, 1f, false, secondary(), Position.START), .5f, 0, 0, 0));
return band;
}
}package dev.cf;
import dev.crossfly.ui.*;
import dev.crossfly.ui.graphics.*;
import dev.crossfly.ui.layout.*;
import dev.crossfly.ui.style.*;
import static dev.cf.sample.CrossFlySamplesColors.*;
/**
* Base class for all CrossFly sample windows.
* <p>
* Provides common infrastructure:
* <ul>
* <li>Shared color palette and styles from {@link dev.cf.sample.CrossFlySamplesColors}</li>
* <li>{@link #addTopBar(String, Button...)} — standard deep-indigo top bar with back button</li>
* <li>{@link #barButton(String, Runnable)} — helper to create icon buttons for the bar</li>
* </ul>
*
* <h3>Usage</h3>
* <pre>
* public class MySample extends SampleWindow {
* public void onAdd(boolean firstTime) throws Exception {
* if (!firstTime) return;
* initWindow();
* addTopBar("My Sample");
* // ... add content
* }
* }
* </pre>
*/
public abstract class SampleWindow extends Window
{
/** The main content area of the window, added by {@link #addTopBar(String, Button...)}, for subclasses to add their content into. */
protected Component contents;
// ─── Top bar ─────────────────────────────────────────────────────────────
/**
* Builds and adds a standard top bar with a back (←) button on the left,
* a centered title, and any optional extra buttons on the right.
*
* @param title the text shown in the bar
* @param rightButtons zero or more icon buttons placed aligned to the right
* @throws Exception if component construction fails
*/
protected void addTopBar(String title, Button... rightButtons) throws Exception
{
fullscreenColor = Styles.backColor.color();
setLayout(new VerticalLayout());
add(0f, buildTopBar(title, rightButtons));
add(LAY_FILL, contents = new Component());
contents.getStyle()
.ingap(Gap.ofFont(0, .5f, 0, .5f));
}
/**
* Same as {@link #addTopBar(String, Button...)}, but returns the bar component
* instead of adding it, for callers that need to position it manually.
*
* @param title the bar title
* @param rightButtons optional right-side icon buttons
* @return the assembled top-bar {@link Component}
* @throws Exception if component construction fails
*/
protected Component buildTopBar(String title, Button... rightButtons) throws Exception
{
Button btBack = barButton("\ue5c4", this::hide); // arrow_back
btBack.testTag("sample.back");
// Padded on every side, like the bar's right buttons: with none above and below, the target
// was the arrow itself, too small to hit on a small phone (iPhone 5s, 17/10/2026).
btBack.getStyle()
.ingap(Gap.ofFont(.75f))
.outgap(Gap.ofFont(0, 0, .25f, 0));
Component bar = new Component().style(barStyle);
bar.setLayout(new GridLayout(Position.START, Position.CENTER));
int n = 2 + rightButtons.length;
Object[] params = new Object[n * 2];
params[0] = 0f;
params[1] = 1f;
for (int i = 0; i < rightButtons.length; i++)
params[2 + i] = 0f;
params[n] = btBack;
params[n + 1] = new Label(title).style(barTitleStyle);
for (int i = 0; i < rightButtons.length; i++)
{
params[n + 2 + i] = rightButtons[i];
rightButtons[i].getStyle()
.ingap(Gap.ofFont(.75f));
}
bar.add(params);
return bar;
}
/**
* Creates a standard bar icon button (transparent, white icon, pressed feedback).
*
* @param materialIcon the Material Icon unicode codepoint string
* @param action the action to run when the button is tapped
* @return the configured {@link Button}
*/
protected Button barButton(String materialIcon, Runnable action)
{
return new Button(new MaterialIcon(materialIcon)).style(barButtonNormal)
.pressedStyle(barButtonPressed)
.onAction(e -> action.run());
}
}本页的机器可读版本,让模型直接读取示例集,而不是猜测 API。