PasswordField（密码框）

JavaFX PasswordField 控件使 JavaFX 应用程序的用户能够输入密码，然后应用程序可以读取该密码。PasswordField 控件不显示输入的文本。相反，它会为每个输入的字符显示一个圆圈。JavaFX PasswordField 控件由 javafx.scene.control.PasswordField 类表示。

A JavaFX PasswordField control enables users of a JavaFX application to enter password which can then be read by the application. The PasswordField control does not show the texted entered into it. Instead it shows a circle for each character entered. The JavaFX PasswordField control is represented by the class javafx.scene.control.PasswordField.

创建 PasswordField

您可以通过创建 PasswordField 类的实例来创建 PasswordField 控件。这是一个 JavaFX PasswordField 实例化的示例：

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

PasswordField passwordField = new PasswordField();

向场景图中添加 PasswordField

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

For a JavaFX PasswordField to be visible the PasswordField object must be added to the scene graph. This means adding it to a Scene object, or as child of a layout which is attached to a Scene object.

这是一个将 JavaFX PasswordField 附加到场景图的示例：

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

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

运行上述 JavaFX PasswordField 示例的结果如下所示：

The result of running the above JavaFX PasswordField example is an application that looks like this:

获取 PasswordField 的文本

您可以使用它的 getText() 方法获取输入到 PasswordField 中的文本，该方法返回一个字符串类型。这是一个完整的示例，它显示了一个 PasswordField 和一个 Button，并在单击按钮时读取输入到 PasswordField 中的文本：

You can get the text entered into a PasswordField using its getText() method which returns a String. Here is a full example that shows a PasswordField and a Button and which reads the text entered into the PasswordField when the button is clicked:

package com.jenkov.javafx.controls;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
public class PasswordFieldExperiments extends Application  {
    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("PasswordField Experiment 1");
        PasswordField passwordField = new PasswordField();
        Button button = new Button("Click to get password");
        button.setOnAction(action -> {
            System.out.println(passwordField.getText());
        });
        HBox hbox = new HBox(passwordField, button);
        Scene scene = new Scene(hbox, 200, 100);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
        Application.launch(args);
    }
}