绑定集合的valueAt()方法

作用：valueAt(index)返回指定index索引下的数据，通过该方法返回的数据可以随着原集合对应位置的数据改变而改变，即绑定到集合的对应位置

ObservableList<String> list = FXCollections.observableArrayList("a", "d", "c");  
SimpleListProperty<String> listProperty = new SimpleListProperty<>(list);  
// 固定索引
ObjectBinding<String> value = listProperty.valueAt(0);  
System.out.println("value.get() = " + value.get());  
listProperty.set(0, "aa");  
System.out.println("value.get() = " + value.get());  
SimpleIntegerProperty integerProperty = new SimpleIntegerProperty(0);  
// 可观察索引
ObjectBinding<String> value1 = listProperty.valueAt(integerProperty);  
System.out.println("value1.get() = " + value1.get());  
integerProperty.set(1);  
listProperty.set(1, "bb");  
System.out.println("value1.get() = " + value1.get());

value.get() = a
value.get() = aa
value1.get() = aa
value1.get() = bb

案例

修改列表中指定位置的字符串，并实时显示

创建控件和数据

VBox vBox = new VBox(10);  
HBox hBox = new HBox(10);  
TextField tx1 = new TextField();  
TextField tx2 = new TextField();  
hBox.getChildren().addAll(tx1, tx2  
VBox listData = new VBox(10);
// 数据  
ObservableList<String> list = FXCollections.observableArrayList("A", "B", "D", "T", "R");  
SimpleListProperty<String> listProperty = new SimpleListProperty<>(list);

显示区域

// 填充标签数据  
for (int i = 0; i < list.size(); i++) {  
    Label label = new Label();  
    label.setFont(new Font(20));  
    label.textProperty().bind(listProperty.valueAt(i));  
    listData.getChildren().add(label);  
}

监听事件

tx2.textProperty().addListener((observable, oldValue, newValue) -> {  
    if (newValue.equals("")){  
        return;  
    }  
    try {  
        int i = Integer.parseInt(tx1.getText());  
        listProperty.set(i, newValue);  
        System.out.println("listProperty.get() = " + listProperty.get());  
    }catch (Exception e){  
        System.err.println("ERROR");  
    }  
});

listProperty.get() = [A, B, a, T, R]
listProperty.get() = [A, B, a'a, T, R]
listProperty.get() = [A, B, aaa, T, R]
listProperty.get() = [A, B, aaaa, T, R]
listProperty.get() = [A, B, 阿阿阿阿, T, R]

# 绑定 集合的valueAt()方法

# 案例

绑定集合的valueAt()方法

案例