从其控制器外部访问节点JavaFX - MVC

Question

我正在构建天气应用程序。有2个场景和2个控制器文件。一个是主屏幕，另一个是“设置”。主FXML包含一个标签，如果用户不想看到额外的信息，就必须在设置页面打开/关闭该标签。我的问题是如何从设置页面的控制器类设置可见标签，如果可能的话。 感谢您的帮助

Answer 1

我假设只有在用户单击主屏幕上的按钮时才会出现设置场景。我最近不得不在我的代码中处理相同的情况。这里是处理这种情况的一个伟大的教程：

http://code.makery.ch/library/javafx-2-tutorial/part1/

1）在你MainScene控制器，你会引用主类，并调用其功能，弹出设置场景。

2）在主类中，你将有弹出的设置场景

3）设置场景后关闭的功能，将通过主类传递值回MainScene控制器和根据返回值您可以设置标签。

1.）您的主场景的MainController将具有对主类的引用以及通过主类调用设置场景的函数。

public class MainController { 

@FXML 
private Label label; 
@FXML 
private Button Settings; 


// Reference to the main application 
private MainApp mainApp; 

/** 
* The constructor. 
* The constructor is called before the initialize() method. 
*/ 
public MainController() { 
} 

/*Tie this function to your button that pops up Settings */ 

private void handleSettingsButton() { 

     /* Here you call a function in the main class and pass the label 
     * to the settings scene controller */ 

     boolean show = mainApp.showSettingsScene(label); 
     if (show) { 
       label.isVisible("True"); 
     } 
     else { 
       label.isVisible("False"); 
     } 
} 

/** 
* Is called by the main application to give a reference back to itself. 
* 
* @param mainApp 
*/ 
public void setMainApp(MainApp mainApp) { 
    this.mainApp = mainApp; 


} 
} 

2）在您的主类（不要与你的主场景相混淆）加载主场景，并调用setMainApp功能，让您的控制器的引用回到主类。

public class MainApp extends Application { 

private Stage primaryStage; 
private BorderPane rootLayout; 

@Override 
public void start(Stage primaryStage) { 
    this.primaryStage = primaryStage; 
    this.primaryStage.setTitle("Main"); 

/*Right when the app is loaded the MainScene shows up.*/ 

    try { 
     // Load the root layout from the fxml file 
     FXMLLoader loader = new FXMLLoader(MainApp.class.getResource("view/MainScene.fxml")); 
/* Get a reference to the controller instance of the main Scene */ 
mainSceneController = loader.getController(); 
    /*Allow the controller to talk to the main class */ 
    mainSceneController.setMainApp(this); 
     rootLayout = (BorderPane) loader.load(); 
     Scene scene = new Scene(rootLayout); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } catch (IOException e) { 
     // Exception gets thrown if the fxml file could not be loaded 
     e.printStackTrace(); 
    } 


} 

/** 
* Returns the main stage. 
* @return 
*/ 
public Stage getPrimaryStage() { 
    return primaryStage; 
} 

/*This function referenced in your main controller will show the Settings 
*Scene and wait to see what the user has selected for the visible or not 
*visible selection. We need to pass the label to it as well, so we 
*accurately load the Settings Scene with the current state of the label 
*/ 

public boolean showSettingsScene(Label label) { 
    try { 
     // Load the fxml file and create a new stage for the popup 
    FXMLLoader loader = new FXMLLoader(MainApp.class.getResource("view/SettingsScene.fxml")); 
settingsSceneController = loader.getController(); 

    /* Here we send the label to the controller instance of the Settings 
    * Scene */ 

    controller.setLabel(label); 
    AnchorPane page = (AnchorPane) loader.load(); 
    Stage dialogStage = new Stage(); 
    dialogStage.setTitle("Settings"); 
    dialogStage.initModality(Modality.WINDOW_MODAL); 
    dialogStage.initOwner(primaryStage); 
    Scene scene = new Scene(page); 
    dialogStage.setScene(scene); 

/* Show the dialog and wait until the user closes it*/ 
dialogStage.showAndWait(); 

/*Return the value that the user has selected for visible or not */ 
return controller.isShowOrHide(); 

    } catch (IOException e) { 
// Exception gets thrown if the fxml file could not be loaded 
e.printStackTrace(); 
    return false; 
    } 
} 

public static void main(String[] args) { 
    launch(args); 
} 
} 

3）中的设置场景控制器看起来类似以下内容：

import... 
public class SettingsSceneController{ 

@FXML private ComboBox showOrHide; 

private Stage dialogStage; 
private Boolean show = false; 
private Label label; 

/** 
* Initializes the controller class. This method is automatically called 
* after the fxml file has been loaded. 
*/ 
@FXML 
private void initialize() { 
    ;I don't know what you have, but if you use a Combobox... 
    showOrHide.getItems().addAll(
      "Show", 
      "Hide",); 

} 

/** 
* Sets the stage of this dialog. 
* @param dialogStage 
*/ 
public void setDialogStage(Stage dialogStage) { 
    this.dialogStage = dialogStage; 
} 

/*The label that was passed from Main Scene Controller to Main Class to 
* here is now used in the function to update the Combobox with the 
* current status of the label */ 
public void setLabel(Label label) { 
    this.label = label; 
    if(label.isVisible){ 
      showOrHide.setValue("Show"); 
      show = true; 
    } 
    else{ 
      showOrHide.setValue("Hide"); 
      show = false; 
    } 
} 



/** 
* Returns true if the user clicked OK, false otherwise. 
* @return 
*/ 
public boolean isShowOrHide() { 
    return show; 
} 

/** 
* Called when the user clicks ok. Attach this in Scene Builder,to the OK, 
* Enter or Apply or whatever you called it button of the Settings Scene 
* It will reflect any change made to the combobox. 
*/ 
@FXML 
private void handleOk() { 
    if (showOrHide.getValue().toString() == "Show") { 
     show= true; 
    } 
    else{ 
     show = false; 
    } 
     dialogStage.close(); 

} 

/** 
* Called when the user clicks cancel if you have a cancel button. 
*/ 
@FXML 
private void handleCancel() { 
    dialogStage.close(); 
} 


} 
} 

我把大多数代码从教程，并定制适合您的解决方案。它有三种类型的反弹，但如果你稍微思考一下，你可以看到它们如何在使用主类的控制器之间进行通信以促进它。我没有测试这个，但它应该非常接近你所需要的。