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我今天正在做一些功课,并完成了作业的所有目标,我相信这会让我满意。然而,在较早的类中,我们使用相同的事件处理程序进行多个操作(在本例中,您要么在文本字段中键入颜色,要么单击按钮以更改框的背景颜色) 。使用一个事件处理程序进行多个操作
我无法弄清楚在这种情况下我该怎么做......我必须在构造函数中选择一个类型吗?如果第一个参数可能是按钮或文本框,那么我认为这会有所帮助。
我只是想弄清楚如何应用DRY(不要重复自己),只要我可以。
public class ColorChooserApplication extends Application
{
@Override
public void start(Stage stage)
{
// Create all UI components
VBox backgroundBox = new VBox(10);
backgroundBox.setPadding(new Insets(10));
HBox topBox = new HBox(10);
HBox bottomBox = new HBox(10);
TextField colorPrompt = new TextField();
colorPrompt.setOnAction(new ColorHandler(colorPrompt, backgroundBox));
Button redButton = new Button("Red");
redButton.setOnAction(new ButtonHandler(redButton, backgroundBox));
Button whiteButton = new Button("White");
whiteButton.setOnAction(new ButtonHandler(whiteButton, backgroundBox));
Button blueButton = new Button("Blue");
blueButton.setOnAction(new ButtonHandler(blueButton, backgroundBox));
// Assemble
topBox.getChildren().add(colorPrompt);
bottomBox.getChildren().addAll(redButton, whiteButton, blueButton);
backgroundBox.getChildren().addAll(topBox, bottomBox);
backgroundBox.setAlignment(Pos.CENTER);
topBox.setAlignment(Pos.CENTER);
bottomBox.setAlignment(Pos.CENTER);
// Set scene and show
stage.setScene(new Scene(backgroundBox));
stage.show();
}
class ColorHandler implements EventHandler<ActionEvent>
{
TextField colorTf;
VBox bgVbox;
public ColorHandler(TextField colorTf, VBox bgVbox)
{
this.colorTf = colorTf;
this.bgVbox = bgVbox;
}
@Override
public void handle(ActionEvent event)
{
String color = colorTf.getText();
bgVbox.setStyle("-fx-background-color:" + color);
}
}
class ButtonHandler implements EventHandler<ActionEvent>
{
Button colorButton;
VBox bgVbox;
public ButtonHandler(Button colorButton, VBox bgVbox)
{
this.colorButton = colorButton;
this.bgVbox = bgVbox;
}
@Override
public void handle(ActionEvent event)
{
String color = colorButton.getText();
bgVbox.setStyle("-fx-background-color:" + color);
}
}
public static void main(String[] args)
{
launch(args);
}
}