java 如何用java制作图片库
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How to make an image gallery with java
提问by ThisBetterWork
For class I'm working on my first GUI application. It's just a simple image viewer with four buttons: Previous, Next, Stop, Play. Previous and Next work fine, but honestly I don't even know how to begin working on the slideshow part (Play & Stop). I know there's a timer class that would probably be handy for controlling the speed as the images change...but I'm not sure what kind of logic is typically used to cycle through the images. Can anyone point me in the right direction, my brain is a little fried at this point :0
对于课堂，我正在开发我的第一个 GUI 应用程序。它只是一个带有四个按钮的简单图像查看器：上一个、下一个、停止、播放。上一个和下一个工作正常，但老实说，我什至不知道如何开始处理幻灯片部分（播放和停止）。我知道有一个计时器类可能会很方便地控制图像变化时的速度……但我不确定通常使用哪种逻辑来循环浏览图像。谁能指出我正确的方向，此时我的大脑有点炸了：0
I've included my code below. I'm new to this, so hopefully people won't be too critical of my technique. If it matters, I'm working in eclipse.
我在下面包含了我的代码。我是新手，所以希望人们不会对我的技术过于挑剔。如果重要的话，我正在日食中工作。
here's my code so far:
到目前为止，这是我的代码：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.TimerTask;
public class ImageGallery extends JFrame
{
private ImageIcon myImage1 = new ImageIcon ("Chrysanthemum.jpg");
private ImageIcon myImage2 = new ImageIcon ("Desert.jpg");
private ImageIcon myImage3 = new ImageIcon ("Jellyfish.jpg");
private ImageIcon myImage4 = new ImageIcon ("Penguins.jpg");
JPanel ImageGallery = new JPanel();
private ImageIcon[] myImages = new ImageIcon[4];
private int curImageIndex=0;
public ImageGallery ()
{
ImageGallery.add(new JLabel (myImage1));
myImages[0]=myImage1;
myImages[1]=myImage2;
myImages[2]=myImage3;
myImages[3]=myImage4;
add(ImageGallery, BorderLayout.NORTH);
JButton PREVIOUS = new JButton ("Previous");
JButton PLAY = new JButton ("Play");
JButton STOP = new JButton ("Stop");
JButton NEXT = new JButton ("Next");
JPanel Menu = new JPanel();
Menu.setLayout(new GridLayout(1,4));
Menu.add(PREVIOUS);
Menu.add(PLAY);
Menu.add(STOP);
Menu.add(NEXT);
add(Menu, BorderLayout.SOUTH);
//register listener
PreviousButtonListener PreviousButton = new PreviousButtonListener ();
PlayButtonListener PlayButton = new PlayButtonListener ();
StopButtonListener StopButton = new StopButtonListener ();
NextButtonListener NextButton = new NextButtonListener ();
//add listeners to corresponding componenets
PREVIOUS.addActionListener(PreviousButton);
PLAY.addActionListener(PlayButton);
STOP.addActionListener(StopButton);
NEXT.addActionListener(NextButton);
}
public static void main (String [] args)
{
ImageGallery frame = new ImageGallery();
frame.setSize(490,430);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
}
class PreviousButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
if(curImageIndex>0 && curImageIndex <= 3)
{ ImageGallery.remove(0);
curImageIndex=curImageIndex-1;
ImageIcon TheImage= myImages[curImageIndex];
ImageGallery.add(new JLabel (TheImage));
ImageGallery.validate();
ImageGallery.repaint();
}
else
{
ImageGallery.remove(0);
ImageGallery.add(new JLabel (myImage1));
curImageIndex=0;
ImageGallery.validate();
ImageGallery.repaint();
}
}
}
class PlayButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
// *need help here*//
}
}
class StopButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
// *need help here*//
}
}
class NextButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
if(curImageIndex>=0 && curImageIndex < 3)
{ ImageGallery.remove(0);
curImageIndex = curImageIndex + 1;
ImageIcon TheImage= myImages[curImageIndex];
ImageGallery.add(new JLabel (TheImage));
ImageGallery.validate();
ImageGallery.repaint();
}
else
{
ImageGallery.remove(0);
ImageGallery.add(new JLabel (myImage4));
curImageIndex=3;
ImageGallery.validate();
ImageGallery.repaint();
}
}
}
}
采纳答案by Brendan Cutajar
These are some guidelines that might get you started:
以下是一些可能会帮助您入门的指南：
First you will need a separate thread to control the changing images. I suggest you write a class that implements TimerTask. Override the run() method in this class. In this run method you should put the functionality to change the current image being displayed (similar to what you did in the next and previous function).
首先，您需要一个单独的线程来控制不断变化的图像。我建议您编写一个实现TimerTask的类。覆盖此类中的 run() 方法。在这个 run 方法中，您应该放置更改当前显示的图像的功能（类似于您在下一个和上一个功能中所做的）。
In the actionPerformed() method for the play button you will need to create an instance of a Timer class and start your timer using the scheduleAtFixedRate(TimerTask task, long delay, long period) method (other methods in this class may be used as well, scheduleAtFixedRate() seem more appropriate though).
在播放按钮的 actionPerformed() 方法中，您需要创建一个 Timer 类的实例并使用 scheduleAtFixedRate(TimerTask task, long delay, long period) 方法（也可以使用此类中的其他方法）来启动您的计时器, scheduleAtFixedRate() 似乎更合适）。
For the stop you will then need to add enough functionality to stop the running timer using the cancel() method in the Timer class
对于停止，您将需要添加足够的功能以使用 Timer 类中的 cancel() 方法停止正在运行的计时器
回答by mKorbel
Why complicating simple things,
为什么要把简单的事情复杂化，
I think that this is job for CardLayoutand for slideshow is there Swing Timer
我认为这是CardLayout和幻灯片的工作，有Swing Timer
回答by trashgod
回答by Paul Vargas
You need use a thread for the slideshow. You can use a flag in the run method for continue with the show or stop if this flag change, for example, a boolean var. One example you can see in http://java.sun.com/developer/technicalArticles/Threads/applet/.
您需要为幻灯片使用线程。您可以在 run 方法中使用一个标志来继续显示或在此标志更改时停止，例如，布尔变量。您可以在http://java.sun.com/developer/technicalArticles/Threads/applet/ 中看到一个示例。
