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@xaatw0

JavaFXのバインド

Last updated at Posted at 2015-12-30

#はじめに
SwingやVC#でGUIを作成しててどうしても面倒くさいのが、画面の値と内部データを同期させること。しかし、JavaFXではプロパティとバインドを使用すれば非常に簡単に実現できるので驚いた。いままで簡単なアプリケーションを使用するときにバインドを使用してきたが、もう少し本格的に取り組もうと思い、やってみました。

#プロパティとバインド

BindingTest.java

@Test
public void NumberBinding(){
       IntegerProperty num1 = new SimpleIntegerProperty(1);
       IntegerProperty num2 = new SimpleIntegerProperty(2);

       NumberBinding sum = Bindings.add(num1,num2);
       assertThat(sum.getValue(), is(3));

       num1.setValue(2);
       assertThat(sum.getValue(), is(4));
}

@Test
public void IntegerProperty(){

       IntegerProperty num1 = new SimpleIntegerProperty(1);
       IntegerProperty num2 = new SimpleIntegerProperty(2);

       IntegerProperty sum = new SimpleIntegerProperty();
       sum.bind(Bindings.add(num1,num2));

       assertThat(sum.getValue(), is(3));

       num1.setValue(2);
       assertThat(sum.getValue(), is(4));
}

@Test
public void IntegerProperty_同じ値にバインド(){

       IntegerProperty num1 = new SimpleIntegerProperty(1);
       IntegerProperty num2 = new SimpleIntegerProperty(2);

       num2.bind(num1);

       assertThat(num1.getValue(), is(1));
       assertThat(num2.getValue(), is(1));

       num1.setValue(2);
       assertThat(num1.getValue(), is(2));
       assertThat(num2.getValue(), is(2));
}

@Test
public void bind(){
       IntegerProperty num1 = new SimpleIntegerProperty(1);
       IntegerProperty num2 = new SimpleIntegerProperty(2);
       num2.bind(num1);

       num1.set(1);

       try{
    	   // num2はnum1にバインドされているため、num2に設定すると例外が発生する
    	   // java.lang.RuntimeException: A bound value cannot be set.

    	   num2.set(2);
    	   fail();
       }catch(RuntimeException e){}
}

@Test
public void bindBidirectional(){
       IntegerProperty num1 = new SimpleIntegerProperty(1);
       IntegerProperty num2 = new SimpleIntegerProperty(2);
       num2.bindBidirectional(num1);

       // bindBidirectionalでバインドすると、num1,num2どちらにも設定できる
       num1.set(1);
       assertThat(num1.getValue(), is(1));
       assertThat(num2.getValue(), is(1));

       num2.set(2);
       assertThat(num1.getValue(), is(2));
       assertThat(num2.getValue(), is(2));
}

@Test
public void IntegerProperty_計算(){

       IntegerProperty base = new SimpleIntegerProperty(10);

       IntegerProperty add = new SimpleIntegerProperty();
       IntegerProperty substract = new SimpleIntegerProperty();
       IntegerProperty multiply = new SimpleIntegerProperty();
       IntegerProperty divide = new SimpleIntegerProperty();
       IntegerProperty negate = new SimpleIntegerProperty();

       add.bind(base.add(10));
       substract.bind(base.subtract(10));
       multiply.bind(base.multiply(10));
       divide.bind(base.divide(10));
       negate.bind(base.negate());

       assertThat(add.get(), is(20));
       assertThat(substract.get(), is(0));
       assertThat(multiply.get(), is(100));
       assertThat(divide.get(), is(1));
       assertThat(negate.get(), is(-10));

       base.set(5);
       assertThat(add.get(), is(15));
       assertThat(substract.get(), is(-5));
       assertThat(multiply.get(), is(50));
       assertThat(divide.get(), is(0));
       assertThat(negate.get(), is(-5));
}

@Test
public void IntegerProperty_比較(){

	IntegerProperty base = new SimpleIntegerProperty(10);

	BooleanProperty isEqualTo = new SimpleBooleanProperty();
	BooleanProperty greaterThan = new SimpleBooleanProperty();
	BooleanProperty lessThan = new SimpleBooleanProperty();
	BooleanProperty greaterThanOrEqualTo = new SimpleBooleanProperty();
	BooleanProperty lessThanOrEqualTo = new SimpleBooleanProperty();

	isEqualTo.bind(base.isEqualTo(10));
	greaterThan.bind(base.greaterThan(10));
	lessThan.bind(base.lessThan(10));
	greaterThanOrEqualTo.bind(base.greaterThanOrEqualTo(10));
	lessThanOrEqualTo.bind(base.lessThanOrEqualTo(10));

	assertThat(isEqualTo.get(), is(true));
	assertThat(greaterThan.get(), is(false));
	assertThat(lessThan.get(),is(false));
	assertThat(greaterThanOrEqualTo.get(), is(true));
	assertThat(lessThanOrEqualTo.get(), is(true));
}

@Test
public void IntegerProperty_台形の面積(){
	// 上底a、下底b、高さh →面積S (a+b) * h /2
	IntegerProperty a = new SimpleIntegerProperty();
	IntegerProperty b = new SimpleIntegerProperty();
	IntegerProperty h = new SimpleIntegerProperty();

	DoubleProperty S = new SimpleDoubleProperty();
	S.bind(a.add(b).multiply(h).divide(2));

	a.set(2);
	b.set(3);
	h.set(4);
	assertThat(S.get(),is(10D));

	a.set(4);
	assertThat(S.get(),is(14D));
}

@Test
public void BooleanBind(){

       IntegerProperty base = new SimpleIntegerProperty(10);

       BooleanProperty blnEquqls10 = new SimpleBooleanProperty();
       blnEquqls10.bind(base.isEqualTo(10));

       BooleanProperty blnGreaterThan10 = new SimpleBooleanProperty();
       blnGreaterThan10.bind(base.greaterThan(10));

       assertThat(blnEquqls10.get(), is(true));
       assertThat(blnGreaterThan10.get(), is(false));

       base.set(11);
       assertThat(blnEquqls10.get(), is(false));
       assertThat(blnGreaterThan10.get(), is(true));
}

@Test
public void BooleanBindAnd(){
	 BooleanProperty boolean1 = new SimpleBooleanProperty();
	 BooleanProperty boolean2 = new SimpleBooleanProperty();

	 BooleanProperty result = new SimpleBooleanProperty();
	 result.bind(boolean1.and(boolean2));

	 assertThat(result.get(), is(false));

	 boolean1.set(true);
	 assertThat(result.get(), is(false));

	 boolean2.set(true);
	 assertThat(result.get(), is(true));
}

@Test
public void BooleanBindOr(){
	 BooleanProperty boolean1 = new SimpleBooleanProperty();
	 BooleanProperty boolean2 = new SimpleBooleanProperty();

	 BooleanProperty result = new SimpleBooleanProperty();
	 result.bind(boolean1.or(boolean2));

	 assertThat(result.get(), is(false));

	 boolean1.set(true);
	 assertThat(result.get(), is(true));

	 boolean2.set(true);
	 assertThat(result.get(), is(true));
}

@Test
public void BooleanBindAndOr(){
	// 1 and (2 or 3)

	BooleanProperty boolean1 = new SimpleBooleanProperty();
	BooleanProperty boolean2 = new SimpleBooleanProperty();
	BooleanProperty boolean3 = new SimpleBooleanProperty();

	BooleanProperty result = new SimpleBooleanProperty();
	result.bind(boolean1.and(boolean2.or(boolean3)));

	assertThat(result.get(), is(false));

	boolean1.set(true);
	assertThat(result.get(), is(false));

	boolean2.set(true);
	assertThat(result.get(), is(true));

	boolean2.set(false);
	boolean3.set(true);
	assertThat(result.get(), is(true));

	boolean1.set(false);
	assertThat(result.get(), is(false));
}

@Test
public void BooleanBindWhenThenOtherwise(){

	// 分子が4，分母が2
	IntegerProperty numerator = new SimpleIntegerProperty(4);
	IntegerProperty denominato = new SimpleIntegerProperty(2);

	// 分母が0でないなら、分子を分母で割った値、
	// 上記以外の場合、0を返す。
	NumberBinding value =
		new When(denominato.isNotEqualTo(0))
		.then(numerator.divide(denominato))
		.otherwise(0);

	assertThat(value.getValue(),is(2));

	numerator.set(7);
	assertThat(value.getValue(),is(3));

	denominato.set(0);
	assertThat(value.getValue(), is(0));
}

@Test
public void StringBind(){
	StringProperty concat = new SimpleStringProperty();
	BooleanProperty isEqualTo = new SimpleBooleanProperty();
	BooleanProperty isEqualToIgnoreCase = new SimpleBooleanProperty();
	BooleanProperty isNotEqualTo = new SimpleBooleanProperty();
	BooleanProperty isNotEqualToIgnoreCase = new SimpleBooleanProperty();
	BooleanProperty isEmpty = new SimpleBooleanProperty();
	BooleanProperty isNotEmpty = new SimpleBooleanProperty();
	BooleanProperty isNull = new SimpleBooleanProperty();

	StringProperty target = new SimpleStringProperty("A");
	concat.bind(target.concat("!"));
	isEqualTo.bind(target.isEqualTo("A"));
	isEqualToIgnoreCase.bind(target.isEqualToIgnoreCase("A"));
	isNotEqualTo.bind(target.isNotEqualTo("A"));
	isNotEqualToIgnoreCase.bind(target.isNotEqualToIgnoreCase("A"));
	isEmpty.bind(target.isEmpty());
	isNotEmpty.bind(target.isNotEmpty());
	isNull.bind(target.isNull());

	assertThat(concat.get(), is("A!"));
	assertThat(isEqualTo.get(),is(true));
	assertThat(isEqualToIgnoreCase.get(),is(true));
	assertThat(isNotEqualTo.get(),is(false));
	assertThat(isNotEqualToIgnoreCase.get(),is(false));
	assertThat(isEmpty.get(), is(false));
	assertThat(isNotEmpty.get(), is(true));
	assertThat(isNull.get(), is(false));

	target.set("a");
	assertThat(concat.get(), is("a!"));
	assertThat(isEqualTo.get(),is(false));
	assertThat(isEqualToIgnoreCase.get(),is(true));
	assertThat(isNotEqualTo.get(),is(true));
	assertThat(isNotEqualToIgnoreCase.get(),is(false));
	assertThat(isEmpty.get(), is(false));
	assertThat(isNotEmpty.get(), is(true));
	assertThat(isNull.get(), is(false));

	target.set("");
	assertThat(concat.get(), is("!"));
	assertThat(isEqualTo.get(),is(false));
	assertThat(isEqualToIgnoreCase.get(),is(false));
	assertThat(isNotEqualTo.get(),is(true));
	assertThat(isNotEqualToIgnoreCase.get(),is(true));
	assertThat(isEmpty.get(), is(true));
	assertThat(isNotEmpty.get(), is(false));
	assertThat(isNull.get(), is(false));

	target.set(null);
	assertThat(concat.get(), is("null!"));
	assertThat(isEqualTo.get(),is(false));
	assertThat(isEqualToIgnoreCase.get(),is(false));
	assertThat(isNotEqualTo.get(),is(true));
	assertThat(isNotEqualToIgnoreCase.get(),is(true));
	assertThat(isEmpty.get(), is(true));
	assertThat(isNotEmpty.get(), is(false));
	assertThat(isNull.get(), is(true));
}

#JavaFXのコントロールにバインドさせてみる
チェックボックスでチェックの有無は、selectedProperty() に設定する。コンポーネントの有効無効はdisableProperty()で設定する。ラベルやテキストフィールドのテキストの内容はtextProperty()で設定する。
それぞれのコンポーネントのプロパティ同士をバインドしたり、BooleanProperty経由でバインドさせたりしてます。

FXController.java
@FXML CheckBox checkBox1;
@FXML CheckBox checkBox2;
@FXML CheckBox checkBox3;
@FXML CheckBox checkBox4;
@FXML CheckBox checkBox5;

@FXML Button button;
@FXML Label label;
@FXML Label lblCheckbox5;

BooleanProperty blnBindBidirectional = new SimpleBooleanProperty();

@Override
public void initialize(URL paramURL, ResourceBundle paramResourceBundle) {

	// 相互に影響し合う
	checkBox1.selectedProperty().bindBidirectional(checkBox2.selectedProperty());

	// チェックボックス3の値は、チェックボックス4に依存するため、
	// チェックボックス3のチェックを変更すると例外発生する
	checkBox3.selectedProperty().bind(checkBox4.selectedProperty());

	// チェックがあるとき、ボタンが入力可能になる
	button.disableProperty().bind(checkBox1.selectedProperty().not());

	// ラベルのテキストは、チェックボックス1のチェックの内容に文字を連結させて出力する
	StringProperty stringProperty = new SimpleStringProperty("");
	stringProperty.bind( checkBox1.selectedProperty().asString().concat(" ←チェックの中身"));
	label.textProperty().bind(stringProperty);

	// チェックボックス5のチェック状況はプロパティと連動させる。
	checkBox5.selectedProperty().bindBidirectional(blnBindBidirectional);
	lblCheckbox5.textProperty().bind(blnBindBidirectional.asString());

	}

	@FXML
	public void buttonPressed(ActionEvent event){
		// BooleanPropertyのtrue/falseを入れかえる
		blnBindBidirectional.set(! blnBindBidirectional.get());
	}
}

#最後に
ここでは紹介していませんが、コレクションのListとJavaFXのListViewの中身をバインドさせたり、コンボボックスの選択肢の基となったオブジェクトとバインドさせたりと、本当に便利です。
ソースは、Githubにありますが、他の投稿のソースも混じってます、すいません。

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