问题
i am a new programmer here and i have something to ask, i have browse a picture into my GUI (and set the path in text box also)which displays on a Label, but the label dimension is set only 100,100 while the picture is much bigger so when i open/display it into the label it get cropped , is there anyway to make it auto resize to the label size? below is my logic code on browse button and open dialog box please any one tell me where i am wrong..
public class ImagePath extends javax.swing.JFrame {
private JPanel contentPane;
JLabel jLabel1;
String s2;
File targetFile;
BufferedImage targetImg;
public ImagePath() {
initComponents();
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser jFileChooser1 = new JFileChooser();
int state = jFileChooser1.showOpenDialog(new JFrame());
jTextField1.setText("");
if (state == JFileChooser.APPROVE_OPTION) {
JOptionPane.showMessageDialog(new JFrame(), "hii");
File file = jFileChooser1.getSelectedFile();
s2 = file.toString();
jTextField1.setText(s2);
jLabel1 = new JLabel();
jLabel1.setName(s2);
jLabel1.setLocation(50, 50);
jLabel1.setSize(300, 300);
add(jLabel1);
BufferedImage bi1;
try {
bi1 = ImageIO.read(file);
ImageIcon icon1 = new ImageIcon(bi1);
jLabel1.setIcon(icon1);
Image img = icon1.getImage();
ImageIcon icon = new ImageIcon(file.getPath());
Image scaleImage = icon.getImage().getScaledInstance(28, 28, Image.SCALE_DEFAULT);
repaint();
pack();
} catch (Exception e) {
System.out.println(e);
}
} else if (state == JFileChooser.CANCEL_OPTION) {
JOptionPane.showMessageDialog(new JFrame(), "Canceled");
}
}
}
回答1:
Unless you really want a nasty head ache, I would suggest taking advantage of the layout management system.
Instead of trying to set the size and location of components, let them decide how they wan to be displayed where possible.
While I personally take advantage of Netbeans form designer, I would encourage you to take the time to learn how to build your UI's by hand, it will give a greater apprication for what the form designers can do, as well ideas you can employee to make advanced UIs - IMHO
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class SimpleImageBrowser {
public static void main(String[] args) {
new SimpleImageBrowser();
}
public SimpleImageBrowser() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new SimpleImageBrowser.ImageBrowserPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ImageBrowserPane extends JPanel {
private JFileChooser fcImage = new JFileChooser();
private SimpleImageBrowser.ImagePane imagePane;
public ImageBrowserPane() {
setLayout(new BorderLayout());
imagePane = new SimpleImageBrowser.ImagePane();
add(new JScrollPane(imagePane));
JButton add = new JButton("Add");
add.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int state = fcImage.showOpenDialog(SimpleImageBrowser.ImageBrowserPane.this);
switch (state) {
case JFileChooser.APPROVE_OPTION:
File file = fcImage.getSelectedFile();
try {
BufferedImage bi1 = ImageIO.read(file);
ImageIcon icon1 = new ImageIcon(bi1);
JLabel label = new JLabel(icon1);
label.setText(file.getPath());
label.setHorizontalTextPosition(JLabel.CENTER);
label.setVerticalTextPosition(JLabel.BOTTOM);
label.setForeground(Color.WHITE);
label.setBorder(new LineBorder(Color.WHITE));
imagePane.add(label);
imagePane.revalidate();
} catch (Exception exp) {
exp.printStackTrace();
}
}
}
});
JPanel buttons = new JPanel();
buttons.add(add);
add(buttons, BorderLayout.NORTH);
}
}
public class ImagePane extends JPanel {
public ImagePane() {
setLayout(new SimpleImageBrowser.WrapLayout());
setBackground(Color.BLACK);
}
@Override
public Dimension getPreferredSize() {
return getComponentCount() == 0 ? new Dimension(200, 200) : super.getPreferredSize();
}
}
/**
* FlowLayout subclass that fully supports wrapping of components.
*/
public class WrapLayout extends FlowLayout {
private Dimension preferredLayoutSize;
/**
* Constructs a new
* <code>WrapLayout</code> with a left alignment and a default 5-unit
* horizontal and vertical gap.
*/
public WrapLayout() {
super();
}
/**
* Constructs a new
* <code>FlowLayout</code> with the specified alignment and a default 5-unit
* horizontal and vertical gap. The value of the alignment argument must be
* one of
* <code>WrapLayout</code>,
* <code>WrapLayout</code>, or
* <code>WrapLayout</code>.
*
* @param align the alignment value
*/
public WrapLayout(int align) {
super(align);
}
/**
* Creates a new flow layout manager with the indicated alignment and the
* indicated horizontal and vertical gaps.
* <p>
* The value of the alignment argument must be one of
* <code>WrapLayout</code>,
* <code>WrapLayout</code>, or
* <code>WrapLayout</code>.
*
* @param align the alignment value
* @param hgap the horizontal gap between components
* @param vgap the vertical gap between components
*/
public WrapLayout(int align, int hgap, int vgap) {
super(align, hgap, vgap);
}
/**
* Returns the preferred dimensions for this layout given the
* <i>visible</i> components in the specified target container.
*
* @param target the component which needs to be laid out
* @return the preferred dimensions to lay out the subcomponents of the
* specified container
*/
@Override
public Dimension preferredLayoutSize(Container target) {
return layoutSize(target, true);
}
/**
* Returns the minimum dimensions needed to layout the <i>visible</i>
* components contained in the specified target container.
*
* @param target the component which needs to be laid out
* @return the minimum dimensions to lay out the subcomponents of the
* specified container
*/
@Override
public Dimension minimumLayoutSize(Container target) {
Dimension minimum = layoutSize(target, false);
minimum.width -= (getHgap() + 1);
return minimum;
}
/**
* Returns the minimum or preferred dimension needed to layout the target
* container.
*
* @param target target to get layout size for
* @param preferred should preferred size be calculated
* @return the dimension to layout the target container
*/
private Dimension layoutSize(Container target, boolean preferred) {
synchronized (target.getTreeLock()) {
// Each row must fit with the width allocated to the containter.
// When the container width = 0, the preferred width of the container
// has not yet been calculated so lets ask for the maximum.
int targetWidth = target.getSize().width;
if (targetWidth == 0) {
targetWidth = Integer.MAX_VALUE;
}
int hgap = getHgap();
int vgap = getVgap();
Insets insets = target.getInsets();
int horizontalInsetsAndGap = insets.left + insets.right + (hgap * 2);
int maxWidth = targetWidth - horizontalInsetsAndGap;
// Fit components into the allowed width
Dimension dim = new Dimension(0, 0);
int rowWidth = 0;
int rowHeight = 0;
int nmembers = target.getComponentCount();
for (int i = 0; i < nmembers; i++) {
Component m = target.getComponent(i);
if (m.isVisible()) {
Dimension d = preferred ? m.getPreferredSize() : m.getMinimumSize();
// Can't add the component to current row. Start a new row.
if (rowWidth + d.width > maxWidth) {
addRow(dim, rowWidth, rowHeight);
rowWidth = 0;
rowHeight = 0;
}
// Add a horizontal gap for all components after the first
if (rowWidth != 0) {
rowWidth += hgap;
}
rowWidth += d.width;
rowHeight = Math.max(rowHeight, d.height);
}
}
addRow(dim, rowWidth, rowHeight);
dim.width += horizontalInsetsAndGap;
dim.height += insets.top + insets.bottom + vgap * 2;
// When using a scroll pane or the DecoratedLookAndFeel we need to
// make sure the preferred size is less than the size of the
// target containter so shrinking the container size works
// correctly. Removing the horizontal gap is an easy way to do this.
Container scrollPane = SwingUtilities.getAncestorOfClass(JScrollPane.class, target);
if (scrollPane != null && target.isValid()) {
dim.width -= (hgap + 1);
}
return dim;
}
}
/*
* A new row has been completed. Use the dimensions of this row
* to update the preferred size for the container.
*
* @param dim update the width and height when appropriate
* @param rowWidth the width of the row to add
* @param rowHeight the height of the row to add
*/
private void addRow(Dimension dim, int rowWidth, int rowHeight) {
dim.width = Math.max(dim.width, rowWidth);
if (dim.height > 0) {
dim.height += getVgap();
}
dim.height += rowHeight;
}
}
}
I've included WrapLayout by Rob Camick (who lurks about the place) because, to be quite frank, none of the other layout managers gave me the effect I wanted.
I also set the label's text with the path of the image
Take a look at Using layout Managers and A Visual Guide to Layout Managers
Take a look at WrapLayout
Updated with text fields
If you want to associate a text field with the image, then I suggest you add both the label and text field to a JPanel (using something like a BorderLayout) and then add that to your image pane...
public class ImagePane extends JPanel {
public ImagePane() {
setLayout(new SimpleImageBrowser.WrapLayout());
setBackground(Color.BLACK);
}
public void addImage(File file) throws IOException {
BufferedImage bi1 = ImageIO.read(file);
ImageIcon icon1 = new ImageIcon(bi1);
JPanel imgPane = new JPanel(new BorderLayout());
imgPane.setOpaque(false);
JLabel label = new JLabel(icon1);
imgPane.add(label);
JTextField field = new JTextField(file.getPath(), 20);
field.setEditable(false);
imgPane.add(field, BorderLayout.SOUTH);
add(imgPane);
revalidate();
}
@Override
public Dimension getPreferredSize() {
return getComponentCount() == 0 ? new Dimension(200, 200) : super.getPreferredSize();
}
}
And the updated ActionListener...
add.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int state = fcImage.showOpenDialog(SimpleImageBrowser.ImageBrowserPane.this);
switch (state) {
case JFileChooser.APPROVE_OPTION:
File file = fcImage.getSelectedFile();
try {
imagePane.addImage(file);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
});
回答2:
You should cut out the call to label.setSize. You should also place all your components in in the form designer instead of producing them when you click the button. Maybe you could also add a layout manager in the bargain? This will really involve a revolt against NetBeans.
来源：https://stackoverflow.com/questions/18010803/java-swing-resize-imageicon-according-to-jlabel