WritableValue e ReadOnlyProperty

A interface WritableValue fornece o método setValue() para um Property. A interface ReadOnlyProperty injeta dois métodos para um Property: um método getBean() que retorna o titular de property e um método getName() que retorna um nome descritivo da property.

Ambos os métodos podem retornar null se o property não é parte de um grande objeto ou se um nome descritivo não é importante.

Table of Contents

Main.java

package sample;

import javafx.animation.*;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.util.Duration;
import main.java.br.com.cursojavanow.AnimationString;


public class Main extends Application {

    @Override
    public void start(Stage stage) throws Exception {
        Scene scene = new Scene(new View(), 300,150);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

    class View extends Group {
        public View() {
            Text text = new Text(50,50,"");

            String str = "あいうえおあいうえおあいうえお\nかきくけこかきくけこかきくけこ";
            AnimationString.Value asv = new AnimationString.Value(str);
            AnimationString as = new AnimationString(text.textProperty());
            KeyValue kv = new KeyValue(as, asv);
            KeyFrame kf = new KeyFrame(Duration.seconds(3), kv);
            Timeline animation = new Timeline(kf);

            animation.setCycleCount(2);
            animation.setAutoReverse(true);
            animation.play();
            getChildren().add(text);
        }
    }

}

package sample;

import javafx.animation.*;

import javafx.application.Application;

import javafx.scene.Group;

import javafx.scene.Scene;

import javafx.scene.text.Text;

import javafx.stage.Stage;

import javafx.util.Duration;

import main.java.br.com.cursojavanow.AnimationString;

public class Main extends Application {

@Override

public void start(Stage stage) throws Exception {

Scene scene = new Scene(new View(), 300,150);

stage.setScene(scene);

stage.show();

}

public static void main(String[] args) {

launch(args);

}

class View extends Group {

public View() {

Text text = new Text(50,50,"");

String str = "あいうえおあいうえおあいうえお\nかきくけこかきくけこかきくけこ";

AnimationString.Value asv = new AnimationString.Value(str);

AnimationString as = new AnimationString(text.textProperty());

KeyValue kv = new KeyValue(as, asv);

KeyFrame kf = new KeyFrame(Duration.seconds(3), kv);

Timeline animation = new Timeline(kf);

animation.setCycleCount(2);

animation.setAutoReverse(true);

animation.play();

getChildren().add(text);

}

AnimationString.java

package main.java.br.com.cursojavanow;

import javafx.animation.Interpolatable;
import javafx.beans.property.StringProperty;
import javafx.beans.value.WritableValue;

public class AnimationString  implements WritableValue<AnimationString.Value> {
    private StringProperty prop;
    private Value value;

    public AnimationString(StringProperty prop) {
        this.prop = prop;
        value = new Value(prop.getValue());
    }

    @Override
    public Value getValue() {
        return value;
    }

    @Override
    public void setValue(Value value) {
        prop.setValue(value.text);
        this.value = value;
    }

    public static class Value implements Interpolatable<Value> {
        private String text;

        public Value(String text) {
            this.text = text;
        }

        @Override
        public Value interpolate(Value endValue, double t) {
            String s = endValue.text;
            int len = s.length() + 1;
            int result = Math.min(s.length(),(int) (t * len));

            if ( result != text.length() ) {
                return new Value(s.substring(0, result));
            }
            return this;
        }
    }
}

package main.java.br.com.cursojavanow;

import javafx.animation.Interpolatable;

import javafx.beans.property.StringProperty;

import javafx.beans.value.WritableValue;

public class AnimationString implements WritableValue<AnimationString.Value> {

private StringProperty prop;

private Value value;

public AnimationString(StringProperty prop) {

this.prop = prop;

value = new Value(prop.getValue());

}

@Override

public Value getValue() {

return value;

}

@Override

public void setValue(Value value) {

prop.setValue(value.text);

this.value = value;

}

public static class Value implements Interpolatable<Value> {

private String text;

public Value(String text) {

this.text = text;

}

@Override

public Value interpolate(Value endValue, double t) {

String s = endValue.text;

int len = s.length() + 1;

int result = Math.min(s.length(),(int) (t * len));

if ( result != text.length() ) {

return new Value(s.substring(0, result));

}

return this;

}

Fonte: https://nompor.com/2018/01/08/post-2385/

Curso Java Para Iniciantes

Fonte: The Definitive Guide to Modern Java Clients with JavaFX

WritableValue e ReadOnlyProperty

Main.java

AnimationString.java

Uma Estrutura Linear de Dados: Array

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