ToggleButton（开关按钮）

JavaFX ToggleButton 是一个要么被选择、要么不被选择的按钮。就像一个开关，当你按下它时它会凹进去（表示按下），而当你下次按下它时它又会弹出来 —— 以表示被选择或未选择。JavaFX ToggleButton 由 javafx.scene.control.ToggleButton 类表示。

A JavaFX ToggleButton is a button that can be selected or not selected. Like a button that stays in when you press it, and when you press it the next time it comes out again. Toggled - not toggled. The JavaFX ToggleButton is represented by the class javafx.scene.control.ToggleButton.

创建一个 ToggleButton

您可以通过创建 ToggleButton 类的实例来创建 JavaFX ToggleButton。下面是创建 JavaFX ToggleButton 实例的示例：

You create a JavaFX ToggleButton by creating an instance of the ToggleButton class. Here is an example of creating a JavaFX ToggleButton instance:

ToggleButton toggleButton1 = new ToggleButton("Left");

此示例创建一个带有文本 Left 的 ToggleButton。

This example creates a ToggleButton with the text Left on.

在场景图中添加 ToggleButton

要使 ToggleButton 可见，您必须将其添加到 JavaFX 场景图中。这意味着将其添加到 Scene，或作为附加到 Scene 对象的布局组件的子节点。

To make a ToggleButton visible you must add it to the JavaFX scene graph. This means adding it to a Scene, or as child of a layout which is attached to a Scene object.

这是一个将 JavaFX ToggleButton 添加到场景图的示例：

Here is an example that attaches a JavaFX ToggleButton to the scene graph:

package com.jenkov.javafx.controls;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.ToggleButton;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
public class ToggleButtonExperiments extends Application  {
    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("HBox Experiment 1");
        ToggleButton toggleButton1 = new ToggleButton("Left");
        HBox hbox = new HBox(toggleButton1);
        Scene scene = new Scene(hbox, 200, 100);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
        Application.launch(args);
    }
}

以下两个屏幕截图展示了运行上述示例代码所产生的应用程序。第一个屏幕截图显示了一个未按下的 ToggleButton，第二个屏幕截图显示了相同的 ToggleButton 被按下（代表其被选择、激活等）：

The application resulting from running the above example code is illustrated in the following two screenshots. The first screenshot shows a ToggleButton which is not pressed, and the second screenshot shows the same ToggleButton pressed (selected, activated etc.):

ToggleButton 文本

您可以通过其 setText() 方法设置或更改 JavaFX ToggleButton 的文本。下面是通过 setText() 更改 JavaFX ToggleButton 文本的示例：

You can set or change the text of a JavaFX ToggleButton via its setText() method. Here is an example of changing the text of a JavaFX ToggleButton via setText():

ToggleButton toggleButton = new ToggleButton("Toggle This!");
toggleButton.setText("New Text");

ToggleButton 字体

您可以通过其 setFont() 方法设置用于呈现 JavaFX ToggleButton 按钮文本的字体。您可以在 Fonts（字体）教程中阅读有关创建字体的更多信息。 下面是设置 JavaFX ToggleButton 字体的示例：

You can set the font to use to render the button text of a JavaFX ToggleButton via its setFont() method. You can read more about creating fonts in Fonts tutorial. Here is an example of setting the font of a JavaFX ToggleButton:

ToggleButton toggleButton = new ToggleButton("Toggle This!");
Font arialFontBold36  = Font.font("Arial", FontWeight.BOLD, 36);
toggleButton.setFont(arialFontBold36);

读取选定状态

ToggleButton 类有一个名为 isSelected 的方法，可让您确定是否选择（按下）了 ToggleButton。如果 ToggleButton 被选中，isSelected() 方法返回一个值为 true 的布尔类型，否则返回 false。这是一个例子：

The ToggleButton class has a method named isSelected which lets you determine if the ToggleButton is selected (pressed) or not. The isSelected() method returns a boolean with the value true if the ToggleButton is selected, and false if not. Here is an example:

boolean isSelected = toggleButton1.isSelected();

开关组（ToggleGroup）

您可以将 JavaFX ToggleButton 实例分组到 ToggleGroup 中。ToggleGroup 最多允许在任何时候切换（按下）一个 ToggleButton。因此，ToggleGroup 中的 ToggleButton 实例的功能类似于单选按钮。

You can group JavaFX ToggleButton instances into a ToggleGroup. A ToggleGroup allows at most one ToggleButton to be toggled (pressed) at any time. The ToggleButton instances in a ToggleGroup thus functions similarly to radio buttons.

这是一个 JavaFX ToggleGroup 的示例：

Here is a JavaFX ToggleGroup example:

ToggleButton toggleButton1 = new ToggleButton("Left");
ToggleButton toggleButton2 = new ToggleButton("Right");
ToggleButton toggleButton3 = new ToggleButton("Up");
ToggleButton toggleButton4 = new ToggleButton("Down");
ToggleGroup toggleGroup = new ToggleGroup();
toggleButton1.setToggleGroup(toggleGroup);
toggleButton2.setToggleGroup(toggleGroup);
toggleButton3.setToggleGroup(toggleGroup);
toggleButton4.setToggleGroup(toggleGroup);

这是一个完整的示例，它将 4 个 ToggleButton 实例添加到 ToggleGroup，并将它们添加到场景图中：

Here is a full example that adds the 4 ToggleButton instances to a ToggleGroup, and adds them to the scene graph too:

package com.jenkov.javafx.controls;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.ToggleButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
public class ToggleButtonExperiments extends Application  {
    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("HBox Experiment 1");
        ToggleButton toggleButton1 = new ToggleButton("Left");
        ToggleButton toggleButton2 = new ToggleButton("Right");
        ToggleButton toggleButton3 = new ToggleButton("Up");
        ToggleButton toggleButton4 = new ToggleButton("Down");
        ToggleGroup toggleGroup = new ToggleGroup();
        toggleButton1.setToggleGroup(toggleGroup);
        toggleButton2.setToggleGroup(toggleGroup);
        toggleButton3.setToggleGroup(toggleGroup);
        toggleButton4.setToggleGroup(toggleGroup);
        HBox hbox = new HBox(toggleButton1, toggleButton2, toggleButton3, toggleButton4);
        Scene scene = new Scene(hbox, 200, 100);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
        Application.launch(args);
    }
}

生成的应用程序如下所示：

The resulting applications looks like this:

读取 ToggleGroup 的选定状态

您可以使用 getSelectedToggle() 方法读取 ToggleGroup 的哪个 ToggleButton 被选中（按下），如下所示：

You can read which ToggleButton of a ToggleGroup is selected (pressed) using the getSelectedToggle() method, like this:

ToggleButton selectedToggleButton =
        (ToggleButton) toggleGroup.getSelectedToggle();

如果没有 ToggleButton 被选中，则 getSelectedToggle() 方法返回 null。

If no ToggleButton is selected the getSelectedToggle() method returns null .