JavaFx：如何在應用程序運行時觀察Anchorpane？

Question

如何檢查錨板內部是否存在某些節點，或者現在不使用可觀察或綁定的方式，我正在使用if語句，如下所示：

if(anchorPane().getChildren().size()>0){
    GridPane table = (GridPane) anchorPane().getChildren().get(0);
    for(int i=1 ; i<=ComboBox().getValue(); i++){
        TextField Text0 = ((TextField)getComponent (i, 0, table));
        TextField Text1 = ((TextField)getComponent (i, 1, table));
        TextField Text2 = ((TextField)getComponent (i, 2, table));
        TextField Text3 = ((TextField)getComponent (i, 3, table));
        TextField Text4 = ((TextField)getComponent (i, 4, table));
        TextField Text5 = ((TextField)getComponent (i, 5, table));
        TextField Text6 = ((TextField)getComponent (i, 6, table));
        TextField Text7 = ((TextField)getComponent (i, 7, table));

        System.out.println(Text0 + " " + Text1 + " " + Text2 + " " + Text3 + " " + Text4 + " " + Text5 + " " + Text6 + " " + Text7);

            }
    }

我想要實現這一點，因為anchorPane().getChildren().size()不會始終保持為0，它將在應用程序的運行狀態期間發生變化。

Answer 1

您可以為可觀察列表是否為空創建布爾綁定：

BooleanBinding empty = Bindings.isEmpty(anchorPane.getChildren());

接着：

empty.addListener((obs, wasEmpty, isNowEmpty) -> {
    if (! isNowEmpty) {
        // ...
    }
});