How to get selected radio button from ToggleGroup

问题:

I an working on JavaFX 8 and SceneBuilder. I created some radio buttons in the FXML File and specified a toggleGroup name to a radio button list in that. So, now I want to get the toggleGroup's selected radio button in my controller, do I need to make all the radio buttons again as fields in the controller, or just the toggleGroup object will get me the selected radio button (the text of that radio button only, not the button object).

回答1:

Let's say you have a toggle group and three radio buttons belonging to that group.

ToggleGroup group = new ToggleGroup();

RadioButton rb1 = new RadioButton("RadioButton1");
rb1.setUserData("RadioButton1");
rb1.setToggleGroup(group);
rb1.setSelected(true);

RadioButton rb2 = new RadioButton("RadioButton2");
rb2.setUserData("RadioButton2");
rb2.setToggleGroup(group);

RadioButton rb3 = new RadioButton("RadioButton3");
rb3.setUserData("RadioButton3");
rb3.setToggleGroup(group);

When you select a radio button from that toggle group, the following changed(...) method will be called.

group.selectedToggleProperty().addListener(new ChangeListener<Toggle>(){
    public void changed(ObservableValue<? extends Toggle> ov, Toggle old_toggle, Toggle new_toggle) {

         if (group.getSelectedToggle() != null) {

             System.out.println(group.getSelectedToggle().getUserData().toString());
             // Do something here with the userData of newly selected radioButton

         }

     } 
});

回答2:

 @FXML
 ToggleGroup right; //I called it right in SceneBuilder.

later somewhere in method.

RadioButton selectedRadioButton = (RadioButton) right.getSelectedToggle();
String toogleGroupValue = selectedRadioButton.getText();

回答3:

This was never properly or thoroughly answered, so I thought I would post the solution I got.

When you create radio buttons in SceneBuilder, then ALSO use SceneBuilder to assign them to a group. The way you access that group via the Controller is to first create a variable of type ToggleGroup in the Controller and name it the exact same name as the one you created in SceneBuilder. Then you can use it. Here is a pseudocode example of how I did it:

// your imports
public class Controller
{
    @FXML ToggleGroup   myGroup; //I called it myGroup in SceneBuilder as well.

    public void myGroupAction(ActionEvent action)
    {
      System.out.println("Toggled: " + myGroup.getSelectedToggle().getUserData().toString());
    }

    public void initialize()
    {
      //whatever initialize code you have here
    }
}

Although the text returned from the getUserData property is lengthy. Here is a way to get just the name of the Radio Button:

myGroup.selectedToggleProperty().addListener(new ChangeListener<Toggle>()
    {
    @Override
    public void changed(ObservableValue<? extends Toggle> ov, Toggle t, Toggle t1)
        {
        RadioButton chk = (RadioButton)t1.getToggleGroup().getSelectedToggle(); // Cast object to radio button
        System.out.println("Selected Radio Button - "+chk.getText());
        }
    });

Hope this helps someone down the road ...