帧的大小设置为500x500,但是当我向其添加图像时,帧会调整大小到图像的大小。我试过用这个
jf.setPreferredSize(new Dimension(500, 500));
然后图像不会出现。
import java.awt.*;
import javax.swing.*;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import java.awt.event.*;
public class Test implements ActionListener {
ImageIcon imgIcon;
JFrame jf ;
JPanel jp_image,jp_option;
BufferedImage img;
Test(){
jf = new JFrame("photo editor");
jf.setPreferredSize(new Dimension(500, 500));
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jp_image = new JPanel();
jp_option = new JPanel();
jp_image.setPreferredSize(new Dimension(200, 500));
jp_option.setPreferredSize(new Dimension(300, 500));
JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,true, jp_option, jp_image);
jf.getContentPane().add(splitPane);
jf.setSize(1900, 1000);
JMenuBar mbar = new JMenuBar();
jf.setJMenuBar(mbar);
JMenu File = new JMenu("File");
JMenuItem New;
File.add(New = new JMenuItem("New..."));
mbar.add(File);
jf.setVisible(true);
New.addActionListener(this);
}
public void actionPerformed(ActionEvent ae){
String arg = ae.getActionCommand();
if(arg.equals("New...")){
File file = null;
JFileChooser chooser = new JFileChooser();
FileNameExtensionFilter filter = new FileNameExtensionFilter(" jpg,gif,jpeg,png", "jpg", "gif" , "jpeg" , "png");
chooser.setFileFilter(filter);
int returnVal = chooser.showOpenDialog(null);
if(returnVal == JFileChooser.APPROVE_OPTION) {
System.out.println("File Choosed: " + chooser.getCurrentDirectory() + "\\" +chooser.getSelectedFile().getName());
file = chooser.getSelectedFile();
}
try{
img = ImageIO.read(file);
jp_image.add(new JLabel(new ImageIcon(img)));
jp_image.setSize(300, 500);
jf.setPreferredSize(new Dimension(500, 500));// no image appears
//jf.pack(); the image appears but the frame resizes
}
catch(Exception e){
System.out.println("No Image Selected");
}
}
}
public static void main(String args[]){
Test t = new Test();
}
}
如何在不调整框架大小的情况下在面板中设置图像。
答案 0 :(得分:3)
您正在向GUI添加组件,但没有告诉组件的容器布局管理器您正在执行此操作。添加JLabel后,请务必在容器上调用repaint()
和revalidate()
。例如:
img = ImageIO.read(file);
jp_image.add(new JLabel(new ImageIcon(img)));
jp_image.setSize(300, 500);
jf.setPreferredSize(new Dimension(500, 500));// no image appears
jp_image.revalidate();
jp_image.repaint();
更好的是 - 在GUI创建时只添加一次的JLabel,并在获取图像时不重新添加它,而只需设置其Icon。例如:
public class Test implements ActionListener {
ImageIcon imgIcon;
JFrame jf;
JPanel jp_image, jp_option;
BufferedImage img;
private JLabel imageLabel = new JLabel();
Test() {
// ...
jp_image.add(imageLabel); //!!
// ...
}
public void actionPerformed(ActionEvent ae) {
String arg = ae.getActionCommand();
if (arg.equals("New...")) {
// ...
try {
img = ImageIO.read(file);
imageLabel.setIcon(new ImageIcon(img)); //!!
} catch (Exception e) {
e.printStackTrace();
}
}