我进入计算机科学专业的第一年，刚刚获得了我的第一个项目，我必须在其中创建一个可以在SQL数据库上执行CRUD操作的应用程序。此应用程序需要具有一个GUI，我们需要为此使用JavaFX。
目前，我不确定如何处理按钮点击。例如，主屏幕上有三个按钮（“帐户”，“个人资料”，“已监视”），每个按钮都会创建一个带有三个按钮（“创建”，“编辑”，“删除”）的新场景。这导致许多lambda表达式彼此嵌套，这使代码看起来很混乱。在下面，您将看到我的代码的一部分：
public class GUI extends Application {
Database db = new Database();
@Override
public void start(Stage stage) throws Exception {
// Three buttons and a Label for the first scene.
Button buttonAccounts = new Button("Accounts");
Button buttonProfiles = new Button("Profiles");
Button buttonWatched = new Button("Watched");
Label pickAnOption = new Label("Pick an option:");
// Two HBoxes, first one for the Label, the other one for the three Buttons.
// Both HBoxes are aligned in the center.
HBox options = new HBox(12);
options.setAlignment(Pos.CENTER);
options.getChildren().addAll(buttonAccounts, buttonProfiles, buttonWatched);
HBox text = new HBox();
text.setAlignment(Pos.CENTER);
text.getChildren().add(pickAnOption);
// The HBoxes are placed in a BorderPane.
// HBox "text" has a top margin of 20 and HBox "options" has a bottom margin of 20.
// This way, the BorderPane will be nicely aligned in the middle of the scene.
BorderPane pane = new BorderPane();
pane.setTop(text);
pane.setMargin(text, new Insets(20, 0, 0 , 0));
pane.setCenter(options);
pane.setMargin(options, new Insets(0, 0, 20, 0));
Scene selectionScreen = new Scene(pane, 500, 100);
stage.setTitle("Netflix Statistix door S. Jaspers, I. Moerenhout en Z. Usmaeva");
stage.setResizable(false);
stage.setScene(selectionScreen);
stage.show();
// EventHandler for the Accounts Button.
buttonAccounts.setOnAction(e -> {
Button buttonCreateAccount = new Button("Create");
Button buttonEditAccount = new Button("Edit");
Button buttonDeleteAccount = new Button("Delete");
Button back = new Button("Back");
Label createEditOrDelete = new Label("Create a new account, or edit/delete an existing account:");
back.setOnAction(e1 -> stage.setScene(selectionScreen));
HBox text1 = new HBox();
text1.setAlignment(Pos.CENTER);
text1.getChildren().add(createEditOrDelete);
HBox options1 = new HBox(12);
options1.setAlignment(Pos.CENTER);
options1.getChildren().addAll(buttonCreateAccount, buttonEditAccount, buttonDeleteAccount);
HBox text2 = new HBox();
text2.setSpacing(50);
text2.getChildren().add(back);
BorderPane pane1 = new BorderPane();
pane1.setTop(text1);
pane1.setMargin(text1, new Insets(15, 0, 0, 0));
pane1.setCenter(options1);
pane1.setMargin(options1, new Insets(0, 0, 15, 0));
pane1.setBottom(text2);
Scene accounts = new Scene(pane1, 500, 100);
stage.setScene(accounts);
// EventHandler for the Create Account button.
buttonCreateAccount.setOnAction(e1 -> {
GridPane grid = new GridPane();
grid.setPadding(new Insets(10, 10, 10, 10));
grid.setVgap(8);
grid.setHgap(10);
Button buttonSave = new Button("Save");
Button buttonCancel = new Button("Cancel");
buttonCancel.setOnAction(e3 -> {
stage.setScene(accounts);
});
Label accountName = new Label("Name:");
Label accountAddress = new Label("Address:");
Label accountCity = new Label("City:");
TextField accountNameInput = new TextField();
TextField accountAddressInput = new TextField();
TextField accountCityInput = new TextField();
grid.add(accountName, 0, 0);
grid.add(accountNameInput, 1, 0);
grid.add(accountAddress, 0, 1);
grid.add(accountAddressInput, 1, 1);
grid.add(accountCity, 0, 2);
grid.add(accountCityInput, 1, 2);
grid.add(buttonSave, 2, 3);
grid.add(buttonCancel, 3, 3);
Scene accountCreation = new Scene(grid);
stage.setScene(accountCreation);
buttonSave.setOnAction(e2 -> {
boolean succeeded = db.createAccount(accountNameInput.getText(), accountAddressInput.getText(), accountCityInput.getText());
if (succeeded) {
new Alert(Alert.AlertType.INFORMATION, "Account successfully created.").show();
} else {
new Alert(Alert.AlertType.WARNING, "Failed to create account.").show();
}
});
});
我对JavaFX还是相当陌生，我想知道是否有任何方法可以使此代码更清晰。任何建议都非常感谢。
我很乐意将此内容发表为评论，但我不能。您检查过FXML吗？它允许您以非常干净和简单的方式设置属性。如果您需要自动完成和检查，那么我建议使用IntelliJ IDEA。这是一篇很好的文章，解释了FXML的优点：https://docs.oracle.com/javafx/2/fxml_get_started/why_use_fxml.htm
GUI类实现EventHandler接口。然后，您可以在代码中编写以下内容：buttonAccounts.setOnAction(this);
handle()方法的参数包含事件的来源，即单击的按钮。您的代码如下所示：
public class GUI extends Application implements EventHandler<Action> {
public void handle(ActionEvent e) {
Object source = e.getSource();
if (source == buttonAccounts) {
// Handle it.
}
else if (source == buttonEditAccount) {
}
// etc.
}
}
ActionEvent参数并返回void的方法，例如private void handleButtons(ActionEvent event) {
Object source = event.getSource();
// As above.
}
然后您可以写...
buttonAccounts.setOnAction(this::handleButtons);