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配方动画162 行 · 1 个文件

Animation

Styles.animationDuration is the house value — match it, so the app moves at one speed. Anything the user waits through twice was too long the first time.

它展示了什么

The three animations, and the question that picks between them.

Motion is a statement about what just happened, so the kind follows the event. Something arrived or left — fade. Something moved from here to there — position. Something is ongoing with no known end — loop. Motion that answers none of those is decoration, and decoration is the first thing a user reads as the app being slow.

None of the three owns a component. Each produces a number over time and hands it to you; what the number means is the screen's business. That is why the same LoopAnimation drives a colour here and could drive a radius, a rotation or an alpha elsewhere.

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.R22Animation"
修改它

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。

正在此处运行CrossFly 0.1.32
正在启动应用…

由 TeaVM 编译为 JavaScript —— 是同一份代码，不是录像。 · 全部示例

它用到了什么

本示例触及的框架类型。带链接的有参考页。

AlphaAnimationButtonColorUtilsComponentGapLabelLoopAnimationPalColorPositionAnimationScreenStylesWidgets

源码

完整无删减。这就是那个文件，不是片段。

原始
dev/cf/recipe/R22Animation.java
package dev.cf.recipe;

import dev.cf.Tones;

import dev.crossfly.ui.*;
import dev.crossfly.ui.animation.*;
import dev.crossfly.ui.color.*;
import dev.crossfly.ui.color.ColorUtils;
import dev.crossfly.ui.graphics.*;
import dev.crossfly.ui.layout.*;
import dev.crossfly.ui.style.*;

import static dev.crossfly.ui.Widgets.*;

/**
 * The three animations, and the question that picks between them.
 *
 * <p>Motion is a statement about <b>what just happened</b>, so the kind follows the event. Something
 * arrived or left — fade. Something moved from here to there — position. Something is ongoing with
 * no known end — loop. Motion that answers none of those is decoration, and decoration is the first
 * thing a user reads as the app being slow.</p>
 *
 * <p>None of the three owns a component. Each produces a <b>number</b> over time and hands it to
 * you; what the number means is the screen's business. That is why the same {@link LoopAnimation}
 * drives a colour here and could drive a radius, a rotation or an alpha elsewhere.</p>
 */
public class R22Animation extends Recipe
{
   private Label fading, moving, pulsing;
   private LoopAnimation loop;

   public String title()
   {
      return "Animation";
   }

   public String note()
   {
      return "Styles.animationDuration is the house value — match it, so the app moves at one"
         + " speed. Anything the user waits through twice was too long the first time.";
   }

   public void build(Component body) throws Exception
   {
      head(body, 0xE65F, "Arriving and leaving", Tones.accent());
      fading = label("I fade out and back", 1.5f, true, Styles.primaryColor, Position.START);
      body.add(LAY_AUTO, outgap(fading, 0, 0, 0, .4f));
      button(body, "Fade it", this::fade);

      head(body, 0xE8D5, "Moving from here to there", Tones.support());
      moving = label("I slide", 1.5f, true, Styles.textColor, Position.START);
      moving.testTag("anim.slide");
      body.add(LAY_AUTO, outgap(moving, 0, 0, 0, .4f));
      button(body, "Slide it", this::slide);

      head(body, 0xE627, "Ongoing, with no end", Tones.highlight());
      pulsing = label("I pulse while something is happening", 1f, false, Styles.captionColor,
         Position.START);
      body.add(LAY_AUTO, outgap(pulsing, 0, 0, 0, .4f));
      button(body, "Start / stop", this::togglePulse);
   }

   private void fade()
   {
      final AlphaAnimation a = new AlphaAnimation(1f, .1f, Styles.animationDuration);
      a.onUpdate(() ->
      {
         // getValue() is the number the animation is at right now. Turning it into an alpha is
         // this screen's decision, not the animation's.
         fading.getStyle()
            .textColor(ColorUtils.withAlpha(Styles.primaryColor.color(), a.getValue()));
         Screen.repaint();
      });
      // Reversing on complete, so the label ends where it started and the demo can be run twice.
      a.onComplete(() ->
      {
         final AlphaAnimation back = new AlphaAnimation(.1f, 1f, Styles.animationDuration);
         back.onUpdate(() ->
         {
            fading.getStyle()
               .textColor(ColorUtils.withAlpha(Styles.primaryColor.color(), back.getValue()));
            Screen.repaint();
         });
         back.start();
      });
      a.start();
   }

   private void slide()
   {
      final PositionAnimation p = new PositionAnimation(0f, 8f, .45f);
      p.onUpdate(() ->
      {
         // An outgap in font units — so the distance is the same on every density, which a
         // distance in pixels is not.
         moving.getStyle()
            .outgap(Gap.ofFont(p.getValue(), 0, 0, 0));
         // invalidateMeasure, not setValidLayout(false): the outgap is read by the PARENT's layout,
         // and invalidating only the label left it where it was - "Slide it" did nothing (iPhone,
         // 17/10/2026).
         moving.invalidateMeasure();
         Screen.repaint();
      });
      p.onComplete(() ->
      {
         moving.getStyle()
            .outgap(Gap.ZERO);
         moving.invalidateMeasure();
         Screen.repaint();
      });
      p.start();
   }

   private void togglePulse()
   {
      if (loop != null && loop.isRunning())
      {
         loop.stop();
         pulsing.getStyle()
            .textColor(Styles.captionColor);
         Screen.repaint();
         return;
      }
      loop = new LoopAnimation(1.2f);
      loop.onUpdate(() ->
      {
         pulsing.getStyle()
            .textColor(ColorUtils.lerpColor(Styles.captionColor.color(),
               Styles.primaryColor.color(), loop.getValue()));
         Screen.repaint();
      });
      loop.start();
   }

   /**
    * Stopping what this screen started.
    *
    * <p>A loop has no end of its own — it runs until told otherwise. Leaving one running when the
    * screen closes gives you a component that repaints forever, holding its whole tree alive, and
    * the symptom is a frame rate that drops a little more with every screen the user visits.</p>
    */
   @Override
   public void onRemove()
   {
      super.onRemove();
      if (loop != null)
         loop.stop();
   }

   private void button(Component body, String text, Runnable r) throws Exception
   {
      Button b = new Button(text);
      b.onAction(c -> r.run());
      body.add(LAY_AUTO, outgap(b, 0, 0, 0, 1.2f));
   }

   private void head(Component body, int icone, String t, PalColor tom) throws Exception
   {
      body.add(LAY_AUTO, Tones.head(icone, t, tom));
   }
}
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