在TabPane中调用selectionModel().select()时发生NPE

Question

下面是我的代码：

public class TabApp implements Initializable {

    @FXML
    Button newButton;
    @FXML
    TabPane tabPane = new TabPane();
    public Tab newTab;
    private SingleSelectionModel<Tab> selectionModel;
    public int zQueryTabCount = 2;

    @FXML
    public void handleNewButton(ActionEvent event) {
        System.out.println("new button is pressed");

        newTab = new Tab();

        selectionModel.select(newTab);

        newTab.setId("Query " + zQueryTabCount);

        newTab.setText("Query " + zQueryTabCount);

        tabPane.getTabs().add(tabPane.getTabs().size(), newTab);

        tabPane.getTabs().get(0).setClosable(false);

        newTab.setClosable(true);

        if (zQueryTabCount < 2) {

            tabPane.getTabs().get(0).setClosable(false);

        }

        zQueryTabCount++;

    }
}

我在selectionModel.select(newTab);行买到了NullPointerException

我怎么解决它呢？

Answer 1

您的selectionModel变量未初始化，也未附加到TabPane。

请改用next call：

[...]
tabPane.getTabs().add(tabPane.getTabs().size(), newTab);

// should be called after tab has been added to TabPane
tabPane.getSelectionModel().select(newTab);