JavaFX入门与创新功能：打造动态用户界面 - CSDN文库

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"Pro JavaFX" 是一本专注于JavaFX 2.0的教程书籍，它在2011年的JavaOne大会上发布后获得了广泛的采纳。本书旨在帮助读者快速入门并深入理解JavaFX的世界，通过一系列章节，从基础的用户界面创建到高级特性的应用，如动态布局、控制使用、集合与并发处理、图表制作、媒体操作、Web服务接入以及JavaFX语言和标记语言的运用。作者们强调实践与创新，鼓励开发者根据自己的热情来探索JavaFX的魅力。第1章"Getting a Jump Start in JavaFX" 引导读者快速了解JavaFX的基本概念和架构，可能包含安装指南、环境配置等内容，让初学者对平台有初步的认识。第2章"Creating a User Interface in JavaFX" 针对用户界面设计展开讲解，介绍如何使用JavaFX的图形用户界面API，构建直观且响应式的界面元素。第3章"Properties and Bindings" 深入探讨JavaFX中的属性绑定机制，帮助读者理解和利用这一特性实现数据驱动的用户界面，提高交互体验。第4章"Building Dynamic UI Layouts in JavaFX" 讲述如何创建可适应不同屏幕尺寸和窗口大小的动态布局，使应用程序具备更好的兼容性和用户体验。第5章"Using the JavaFX UI Controls" 详述JavaFX内置的各种控件，如按钮、文本框、列表等，以及如何定制它们的外观和行为。第6章"Collections and Concurrency" 探讨JavaFX中的并发编程，包括集合框架的使用和多线程处理，确保程序的性能和正确性。第7章"Creating Charts in JavaFX" 介绍如何利用JavaFX构建各类图表，如折线图、柱状图等，用于数据可视化和分析。第8章"Using the Media Classes" 讨论如何集成音频和视频播放功能，以及处理多媒体内容的常见问题和最佳实践。第9章"Accessing Web Services" 指导读者如何通过JavaFX调用和整合外部Web服务，实现数据获取和交互功能。第10章"JavaFX Languages and Markup" 阐述JavaFX支持的标记语言，如FXML，如何简化界面设计和组件管理。附录"The Visage Language in Depth" 对JavaFX中可能使用的Visage语言进行深度剖析，这是一种用于声明式编程的高级工具。整本书以实际案例和示例为引领，使读者能够逐步掌握JavaFX技术，并激发他们在实践中发挥创造力。正如Howard Thurman所说，书中鼓励开发者追寻自己内心的激情，因为世界真正需要的是那些充满活力和创新精神的人。

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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