Qué muestra esto
Making the user wait, in the three shapes waiting actually comes in.
The choice is not decoration: it is whether you know how long. A spinner over a job whose length you know throws away the only reassurance the user wants; a percentage over a job whose length you are guessing is a lie they will catch at 99%.
Ejecutarlo en tu máquina
Cada ejemplo es una Window normal, así que el lanzador solo necesita su nombre.
gradlew lwjgl3:run --args="classname dev.cf.recipe.R13Waiting"Java se compila antes de ejecutarse, así que el navegador no puede reconstruir una edición por su cuenta: el código que ves aquí se convirtió en JavaScript con TeaVM antes de publicarse. Copia el archivo a un proyecto y funciona sin cambios en las cuatro plataformas; el comando de arriba es toda la preparación.
Qué usa
Tipos del framework que toca este ejemplo. Los enlazados tienen página de referencia.
El código
Completo, sin recortes. Es el archivo, no un fragmento.
package dev.cf.recipe;
import dev.cf.Tones;
import dev.crossfly.Main;
import dev.crossfly.PlatformUtils;
import dev.crossfly.ui.*;
import dev.crossfly.ui.color.*;
import dev.crossfly.ui.graphics.*;
import dev.crossfly.ui.layout.*;
import dev.crossfly.ui.skin.Skin;
import dev.crossfly.ui.style.*;
import static dev.crossfly.ui.Widgets.*;
/**
* Making the user wait, in the three shapes waiting actually comes in.
*
* <p>The choice is not decoration: it is whether you know how long. A spinner over a job whose
* length you know throws away the only reassurance the user wants; a percentage over a job whose
* length you are guessing is a lie they will catch at 99%.</p>
*/
public class R13Waiting extends Recipe
{
private Progress bar;
private RadialProgress ring;
private boolean running;
public String title()
{
return "Waiting";
}
public String note()
{
return "Known length gets a bar. Unknown gets a spinner. A finished measurement — a share, a"
+ " score — gets a ring, and that one is not waiting at all.";
}
public void build(Component body) throws Exception
{
head(body, 0xE88B, "Unknown length", Tones.support());
Progress spin = new Progress(Styles.progressType());
spin.style(Skin.get()
.progress()
.autoWidth(Relative.ofFont(12f)));
body.add(LAY_AUTO, outgap(spin, 0, 0, 0, 1.2f));
head(body, 0xE9E4, "Known length", Tones.accent());
bar = new Progress(0f, 1f);
bar.style(Skin.get()
.progress()
.autoWidth(Relative.ofFont(16f)));
body.add(LAY_AUTO, outgap(bar, 0, 0, 0, .5f));
Button go = Tones.action("Run it");
go.onAction(c -> run());
body.add(LAY_AUTO, outgap(go, 0, 0, 0, 1.2f));
head(body, 0xE6C4, "Not waiting — a measurement", Tones.highlight());
ring = new RadialProgress().progress(.41f)
.text("41%")
.caption("converted");
body.add(LAY_AUTO, ring);
}
/**
* The work runs off the paint thread and reports back through it.
*
* <p>Advancing the bar from the paint thread means the bar cannot advance: the thread that would
* draw it is the thread doing the work. This is the single most common reason a progress bar
* jumps from 0 to 100 with nothing in between.</p>
*
* <p><b>And "off the paint thread" has two shapes, because one platform has one thread.</b>
* {@link PlatformUtils#hasThreads()} is false in the browser: there the work is cut into slices
* and each slice runs from a timer, so the page paints between them. Asking the question instead
* of assuming a thread is what makes this recipe correct on all five — until 28/09/2026 it
* started a {@code Thread} unconditionally, which is exactly the code a reader would copy.</p>
*/
private void run()
{
if (running)
return;
running = true;
if (!PlatformUtils.instance.hasThreads())
{
final int[] step = {0};
final com.badlogic.gdx.utils.Timer.Task[] task = new com.badlogic.gdx.utils.Timer.Task[1];
task[0] = addTimer(() ->
{
// One slice of work per tick: this runs ON the paint thread, so it must be short.
bar.setValue(++step[0] / 20f);
Screen.repaint();
if (step[0] >= 20)
{
removeTimer(task[0]);
running = false;
}
}, .09f);
return;
}
new Thread(() ->
{
for (int i = 1; i <= 20; i++)
{
final float f = i / 20f;
Main.runOnPaintThread(() ->
{
bar.setValue(f);
Screen.repaint();
});
try
{
Thread.sleep(90);
}
catch (InterruptedException e)
{
Thread.currentThread()
.interrupt();
break;
}
}
running = false;
}, "recipe-progress").start();
}
private void head(Component body, int icone, String t, PalColor tom) throws Exception
{
body.add(LAY_AUTO, Tones.head(icone, t, tom));
}
}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());
}
}Versiones de esta página legibles por máquina, para que un modelo lea el estante en vez de adivinar la API.