JavaFX 2入门指南：探索动态UI与多媒体应用 - CSDN文库

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"Pro JavaFX 2.pdf 是一本专注于JavaFX 2的入门教程，旨在帮助读者快速掌握JavaFX的基础知识。这本书包含了多个章节，详细介绍了如何使用JavaFX创建用户界面、处理属性与绑定、构建动态布局、使用UI控件、处理集合与并发、创建图表、利用媒体类、访问Web服务以及使用特定的语言和标记。此外，还包含一个关于Visage语言深入探讨的附录。" JavaFX是Java平台上的一个强大的富客户端应用开发框架，用于构建桌面、移动和Web应用程序。JavaFX 2是其一个重要版本，提供了许多改进和新特性，使得开发者可以创建具有丰富图形效果和交互性的应用程序。本书的第一章"Getting a Jump Start in JavaFX"引导读者快速入门，介绍了JavaFX的基本概念和环境设置，帮助开发者建立对JavaFX平台的理解，并开始编写第一个JavaFX程序。第二章"Creating a User Interface in JavaFX"深入讨论了如何设计和构建用户界面，包括控件的使用、布局管理器和事件处理机制。第三章"Properties and Bindings"讲解了JavaFX中的属性和绑定，这是实现数据驱动用户界面的关键，允许开发者动态响应数据变化。第四章"Building Dynamic UI Layouts in JavaFX"则关注于如何创建动态布局，使界面能够根据需要自动调整。第五章"Using the JavaFX UI Controls"涵盖了JavaFX提供的各种内置控件，如按钮、文本框、菜单等，以及如何自定义控件。第六章"Collections and Concurrency"讨论了在JavaFX中处理集合数据以及并发编程的策略，确保应用的性能和稳定性。第七章"Creating Charts in JavaFX"指导读者如何利用JavaFX创建各种图表，如折线图、柱状图和饼图，用于数据可视化。第八章"Using the Media Classes"介绍如何集成音频和视频到JavaFX应用中，支持多媒体功能。第九章"Accessing Web Services"阐述了如何与Web服务进行交互，如SOAP和RESTful服务，使JavaFX应用能够获取和发送网络数据。第十章"JavaFX Languages and Markup"探讨了JavaFX脚本语言和标记语言的使用，如FXML，用于声明式地构建用户界面。附录"The Visage Language in Depth"深入讲解了一种特定的语言，可能是JavaFX的一个扩展或补充，帮助开发者提升应用的复杂性和表现力。这本书全面覆盖了JavaFX 2的主要方面，对于希望学习或提升JavaFX技能的开发者来说，是一份宝贵的参考资料。通过阅读和实践书中的示例，读者将能够熟练地运用JavaFX来构建现代、互动且美观的应用程序。

CHAPTER 1 ■ GETTING A JUMP START IN JAVAFX

13

javafx.scene.image package and the Group class in the javafx.scene package. In both cases, they inherit

from the Node class.

■ Tip We can’t emphasize enough the importance of having the JavaFX API documentation handy while

reading this book. As classes, variables, and functions are mentioned, it’s often a good idea to look at the

documentation to get more information. In addition, this habit helps you become more familiar with what is

available to you in the API.

Displaying Images

As shown in the following code, displaying an image entails using an ImageView instance in conjunction

with an Image instance.

ImageViewBuilder.create()

.image(new Image("http://projavafx.com/images/earthrise.jpg"))

.build(),

The Image instance identifies the image resource and loads it from the URL assigned to its URL

variable. Both of these classes are located in the javafx.scene.image package.

Working with Graphical Nodes as a Group

One powerful graphical feature of JavaFX is the ability to create scene graphs, which consist of a tree of

graphical nodes. You can then assign values to properties of a Group located in the hierarchy, and the

nodes contained in the Group will be affected. In our current example from Listing 1-1, we’re using a

Group to contain a Text node and to clip a specific rectangular region within the Group so that the text

doesn’t appear on the moon or the Earth as it animates upward. Here’s the relevant code snippet:

GroupBuilder.create()

.layoutX(50)

.layoutY(180)

.children(

textRef

)

.clip(

RectangleBuilder.create()

.width(430)

.height(85)

.build()

)

.build()

Notice that the Group is located 50 pixels to the right and 180 pixels down, from where it would have

been located by default. This is due to the values assigned to the layoutX and layoutY variables of the

Group instance. Because this Group is contained directly by the Scene, its upper-left corner’s location is

CHAPTER 1 ■ GETTING A JUMP START IN JAVAFX

15

The layoutX and layoutY properties of the Group just described are examples of our earlier

statement that nodes contained in a Group will be affected by values assigned to properties of the

Group. Another example is setting the opacity property of a Group instance to 0.5, which causes all of

the nodes contained in that Group to become translucent. If the JavaFX API documentation is handy,

look at the properties available in the javafx.scene.Group class. Then look at the properties available in

the javafx.scene.Node class properties, which is where you’ll find the layoutX, layoutY, and opacity

variables that are inherited by the Group class.

Drawing Text

In the previous snippet, notice that several variables are available in the Text class. This particular

example is a little more complicated than the normal use of the Text class. Let’s first look at a typical

case, shown in the following snippet, in which you simply want to draw a string of text characters

somewhere in the scene.

TextBuilder.create()

.layoutX(65)

.layoutY(12)

.textOrigin(VPos.TOP)

.fill(Color.WHITE)

.text("Audio Configuration")

.font(Font.font("SansSerif", FontWeight.BOLD, 20))

.build(),

This snippet, borrowed from the Audio Configuration example in Figure 1-7 and Listing 1-3 later in

this chapter, draws the graphical Text string “Audio Configuration” in a bold Sans Serif font. The font

size is 20, and the color of the text is white.

Referring again to the JavaFX API documentation, notice that the VPos enum (in the javafx.geometry

package) has fields that serve as constants, for example, BASELINE, BOTTOM, and TOP. These control

the origin of the text with respect to vertical locations on the displayed Text:

• The TOP origin, as we’re using it in the previous code snippet, places the top of the

text (including ascenders) at the layoutY position, relative to the co-ordinate space

in which the Text is located.

• The BOTTOM origin would place the bottom of the text, including descenders

(located in a lowercase “g”, for example) at the layoutY position.

• The BASELINE origin would place the baseline of the text (excluding descenders)

at the layoutY position. This is the default value for the textOrigin property of a

Text instance.

While you’re looking at the javafx.scene.text package in the API documentation, take a look at the

font function of the Font class, which is used in the previous snippet to define the font family, weight,

and size of the Text.

CHAPTER 1 ■ GETTING A JUMP START IN JAVAFX

16

Turning back again to the Hello Earthrise example in Listing 1-1, we’re using some additional

properties of the Text class that enable it to flow from one line to the next:

• The wrappingWidth property enables you to specify at what number of pixels the

text will wrap.

• The textAlignment property enables you to control how the text will be justified. In

our example, TextAlignment.JUSTIFY aligns the text on both the left and right

sides, expanding the space between words to achieve that.

The text that we’re displaying is sufficiently long to wrap and be drawn on the Earth, so we need to

define a rectangular region outside of which that text can’t be seen.

Clipping Graphical Areas

To define a clipping area, we assign a Node subclass to the clip property that defines the clipping shape,

in this case a Rectangle that is 430 pixels wide and 85 pixels high. In addition to keeping the Text from

covering the moon, when the Text scrolls up as a result of animation the clipping area keeps the Text

from covering the earth.

Animating the Text to Make It Scroll Up

When the HelloEarthriseMain program is invoked, the Text begins scrolling up slowly. To achieve this

animation, we’re using the TranslateTransition class located in the javafx.animation package, as shown

in the following snippet from Listing 1-1.

TranslateTransition transTransition = TranslateTransitionBuilder.create()

.duration(new Duration(75000))

.node(textRef)

.toY(-820)

.interpolator(Interpolator.LINEAR)

.cycleCount(Timeline.INDEFINITE)

.build();

...code omitted...

// Start the text animation

transTransition.play();

The javafx.animation package contains convenience classes for animating nodes. This

TranslateTransition instance (created by the TranslateTransitionBuilder class) translates the Text node

referenced by the textRef variable from its original Y position of 100 pixels to a Y position of –820 pixels,

over a duration of 75 seconds. The Interpolator.LINEAR constant is assigned to the interpolator

property, which causes the animation to proceed in a linear fashion. A look at the API docs for the

Interpolator class in the javafx.animation package reveals that there are other forms of interpolation

available, one of which is EASE_OUT, which slows down the animation toward the end of the specified

duration.

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