JavaFX入门教程：从零开始探索JavaFX技术 - CSDN文库

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本资源是一本英文版的JavaFX入门教程，由Apress出版社编写，旨在帮助读者快速上手JavaFX编程。JavaFX是Sun Microsystems（后被Oracle收购）在2007年的Java One大会上推出的一款用于构建桌面、移动和网页应用的图形用户界面（GUI）技术。书中详细介绍了从基础到进阶的内容，包括但不限于： 1. **第1章：JavaFX入门** - 引导读者快速了解JavaFX的概念，介绍其在Java平台上的定位，以及为何对开发者具有吸引力。 2. **第2章：创建用户界面** - 介绍了如何使用JavaFX设计和构建用户界面，涵盖了基本组件的使用和布局管理。 3. **第3章：属性和绑定** - 讲述了如何通过属性和数据绑定实现UI元素之间的交互，提高用户体验的响应性和实时性。 4. **第4章：动态布局** - 探讨了如何利用JavaFX创建可适应不同屏幕尺寸和设备的动态布局，确保跨平台兼容性。 5. **第5章：JavaFX UI控件** - 深入解析常用的JavaFX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。 6. **第6章：集合和并发** - 学习如何处理数据结构和多线程编程，这对于高效管理和并行操作在JavaFX中的应用至关重要。 7. **第7章：创建图表** - 描述了如何使用JavaFX内置的图表库来展示数据，进行可视化分析。 8. **第8章：媒体处理** - 讨论了如何集成音频、视频和其他多媒体内容，增强应用的多媒体功能。 9. **第9章：访问Web服务** - 展示如何利用JavaFX与外部数据源交互，实现数据获取和处理。 10. **第10章：JavaFX语言和标记** - 阐述了JavaFX语法、CSS样式以及如何结合使用它们来提升界面设计的灵活性。 11. **附录：Visage语言深度探索** - 对JavaFX的高级特性或特定语言Visage进行深入讲解，适合进一步学习和研究。整个教程以实例驱动，注重实践，旨在让读者在实际项目中掌握JavaFX开发技能。书中还可能包含作者和审稿人的介绍，以及致谢部分。通过阅读这本书，读者不仅能够了解JavaFX的基本架构，还能学习到如何将JavaFX技术应用到日常开发工作中，创造出引人注目的应用。

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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