Javafx 简明教程

JavaFX - UI Controls

UI Controls 是允许用户与应用程序或网站交互的图形元素。它们包括按钮、菜单、滑块、文本字段、复选框、单选按钮等等。在本教程中，我们将探讨 JavaFX 的不同类型的 UI 控件。

UI Controls are the graphical elements that allow users to interact with an application or a website. They include buttons, menus, sliders, text fields, checkboxes, radio buttons, and more. In this tutorial, we will explore the different types of UI Controls of JavaFX.

让我们从介绍用户界面的三个主要方面来开始讨论——

let’s start the discussion by introducing three main aspects of an user interface −

UI elements − These are the core visual elements which the user eventually sees and interacts with. JavaFX provides a huge list of widely used and common elements varying from basic to complex, which we will cover in this tutorial.
Layouts − They define how UI elements should be organized on the screen and provide a final look and feel to the GUI (Graphical User Interface). This part will be covered in the Layout chapter.
Behavior − These are events which occur when the user interacts with UI elements. This part will be covered in the Event Handling chapter.

为了创建 GUI 组件（控件），JavaFX 支持几种控件，例如日期选择器、按钮文本字段等。这些控件由包 javafx.scene.control 的不同类表示。我们可以通过实例化其相应的类来创建一个控件。

To create GUI components (controls), JavaFX supports several controls such as date picker, button text field, etc. These controls are represented by different classes of the package javafx.scene.control. We can create a control by instantiating its respective class.

以下是设计 JavaFX 中的 GUI 时使用的常用控件列表。

Following is the list of common controls used while designing the GUI in JavaFX.

S.No	Control & Description
1	Label A Label object is a component for placing text.
2	Button This class creates a labeled button.
3	ColorPicker A ColorPicker provides a pane of controls designed to allow a user to manipulate and select a color.
4	CheckBox A CheckBox is a graphical component that can be in either an on(true) or off (false) state.
5	RadioButton The RadioButton class is a graphical component, which can either be in a ON (true) or OFF (false) state in a group.
6	ListView A ListView component presents the user with a scrolling list of text items.
7	TextField A TextField object is a text component that allows for the editing of a single line of text.
8	PasswordField A PasswordField object is a text component specialized for password entry.
9	Scrollbar A Scrollbar control represents a scroll bar component in order to enable user to select from range of values.
10	FileChooser A FileChooser control represents a dialog window from which the user can select a file.
11	ProgressBar As the task progresses towards completion, the progress bar displays the task’s percentage of completion.
12	Slider A Slider lets the user graphically select a value by sliding a knob within a bounded interval.

Example

以下程序是一个示例，在 JavaFX 中显示登录页面。在此，我们使用控件 label, text field, password field 和 button 。将代码保存在一个名为 LoginPage.java 的文件中。

The following program is an example which displays a login page in JavaFX. Here, we are using the controls label, text field, password field and button. Save this code in a file with the name LoginPage.java.

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.layout.GridPane;
import javafx.scene.text.Text;
import javafx.scene.control.TextField;
import javafx.stage.Stage;

public class LoginPage extends Application {
   @Override
   public void start(Stage stage) {
      //creating label email
      Text text1 = new Text("Email");

      //creating label password
      Text text2 = new Text("Password");

      //Creating Text Filed for email
      TextField textField1 = new TextField();

      //Creating Text Filed for password
      PasswordField textField2 = new PasswordField();

      //Creating Buttons
      Button button1 = new Button("Submit");
      Button button2 = new Button("Clear");

      //Creating a Grid Pane
      GridPane gridPane = new GridPane();

      //Setting size for the pane
      gridPane.setMinSize(400, 200);

      //Setting the padding
      gridPane.setPadding(new Insets(10, 10, 10, 10));

      //Setting the vertical and horizontal gaps between the columns
      gridPane.setVgap(5);
      gridPane.setHgap(5);

      //Setting the Grid alignment
      gridPane.setAlignment(Pos.CENTER);

      //Arranging all the nodes in the grid
      gridPane.add(text1, 0, 0);
      gridPane.add(textField1, 1, 0);
      gridPane.add(text2, 0, 1);
      gridPane.add(textField2, 1, 1);
      gridPane.add(button1, 0, 2);
      gridPane.add(button2, 1, 2);
      gridPane.setStyle("-fx-background-color: BEIGE;");

      //Creating a scene object
      Scene scene = new Scene(gridPane);

      //Setting title to the Stage
      stage.setTitle("CSS Example");

      //Adding scene to the stage
      stage.setScene(scene);

      //Displaying the contents of the stage
      stage.show();
   }
   public static void main(String args[]){
      launch(args);
   }
}

使用以下命令，从命令提示符编译并执行已保存的 java 文件。

Compile and execute the saved java file from the command prompt using the following commands.

javac --module-path %PATH_TO_FX% --add-modules javafx.controls LoginPage.java
java --module-path %PATH_TO_FX% --add-modules javafx.controls LoginPage

Output

执行后，上述程序会生成如下所示的 JavaFX 窗口。

On executing, the above program generates a JavaFX window as shown below.