Java/Swing JFC/Panel
Содержание
Determining When a Component Is Added or Removed from a Container
<source lang="java">
import java.awt.ruponent; import java.awt.event.ContainerAdapter; import java.awt.event.ContainerEvent; import java.awt.event.ContainerListener; import javax.swing.JFrame; public class Main {
public static void main() {
ContainerListener listener = new ContainerAdapter() {
public void componentAdded(ContainerEvent evt) {
Component c = evt.getChild();
}
public void componentRemoved(ContainerEvent evt) {
Component c = evt.getChild();
}
};
JFrame frame = new JFrame();
frame.addContainerListener(listener);
}
}
</source>
Getting the Child Components of a Container
<source lang="java">
import java.awt.ruponent; import java.awt.Rectangle; import javax.swing.JFrame; public class Main {
public static void main() {
JFrame container = new JFrame();
Component[] components = container.getComponents();
for (int i = 0; i < components.length; i++) {
Rectangle bounds = components[i].getBounds();
}
}
}
</source>
Horizontal Split Pane based on JPanel
<source lang="java">
/* Copyright (c) 2006, 2009, Carl Burch. License information is located in the
* com.cburch.logisim.Main source code and at www.cburch.ru/logisim/. */
import java.awt.Color; import java.awt.ruponent; import java.awt.Container; import java.awt.Cursor; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Insets; import java.awt.LayoutManager; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import javax.swing.JComponent; import javax.swing.JPanel; public class HorizontalSplitPane extends JPanel {
static final int DRAG_TOLERANCE = 3;
private static final Color DRAG_COLOR = new Color(0, 0, 0, 128);
abstract static class Dragbar extends JComponent
implements MouseListener, MouseMotionListener {
private boolean dragging = false;
private int curValue;
Dragbar() {
addMouseListener(this);
addMouseMotionListener(this);
}
abstract int getDragValue(MouseEvent e);
abstract void setDragValue(int value);
public void paintComponent(Graphics g) {
if(dragging) {
g.setColor(DRAG_COLOR);
g.fillRect(0, 0, getWidth(), getHeight());
}
}
public void mouseClicked(MouseEvent e) { }
public void mousePressed(MouseEvent e) {
if(!dragging) {
curValue = getDragValue(e);
dragging = true;
repaint();
}
}
public void mouseReleased(MouseEvent e) {
if(dragging) {
dragging = false;
int newValue = getDragValue(e);
if(newValue != curValue) setDragValue(newValue);
repaint();
}
}
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void mouseDragged(MouseEvent e) {
if(dragging) {
int newValue = getDragValue(e);
if(newValue != curValue) setDragValue(newValue);
}
}
public void mouseMoved(MouseEvent e) { }
}
private class MyLayout implements LayoutManager {
public void addLayoutComponent(String name, Component comp) { }
public void removeLayoutComponent(Component comp) { }
public Dimension preferredLayoutSize(Container parent) {
if(fraction <= 0.0) return comp1.getPreferredSize();
if(fraction >= 1.0) return comp0.getPreferredSize();
Insets in = parent.getInsets();
Dimension d0 = comp0.getPreferredSize();
Dimension d1 = comp1.getPreferredSize();
return new Dimension(in.left + Math.max(d0.width, d1.width) + in.right,
in.top + d0.height + d1.height + in.bottom);
}
public Dimension minimumLayoutSize(Container parent) {
if(fraction <= 0.0) return comp1.getMinimumSize();
if(fraction >= 1.0) return comp0.getMinimumSize();
Insets in = parent.getInsets();
Dimension d0 = comp0.getMinimumSize();
Dimension d1 = comp1.getMinimumSize();
return new Dimension(in.left + Math.max(d0.width, d1.width) + in.right,
in.top + d0.height + d1.height + in.bottom);
}
public void layoutContainer(Container parent) {
Insets in = parent.getInsets();
int maxWidth = parent.getWidth() - (in.left + in.right);
int maxHeight = parent.getHeight() - (in.top + in.bottom);
int split;
if(fraction <= 0.0) {
split = 0;
} else if(fraction >= 1.0) {
split = maxWidth;
} else {
split = (int) Math.round(maxHeight * fraction);
split = Math.min(split, maxHeight - comp1.getMinimumSize().height);
split = Math.max(split, comp0.getMinimumSize().height);
}
comp0.setBounds(in.left, in.top,
maxWidth, split);
comp1.setBounds(in.left, in.top + split,
maxWidth, maxHeight - split);
dragbar.setBounds(in.left, in.top + split - DRAG_TOLERANCE,
maxWidth, 2 * DRAG_TOLERANCE);
}
}
private class MyDragbar extends Dragbar {
MyDragbar() {
setCursor(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR));
}
int getDragValue(MouseEvent e) {
return getY() + e.getY() - HorizontalSplitPane.this.getInsets().top;
}
void setDragValue(int value) {
Insets in = HorizontalSplitPane.this.getInsets();
setFraction((double) value / (HorizontalSplitPane.this.getHeight() - in.bottom - in.top));
revalidate();
}
}
private JComponent comp0;
private JComponent comp1;
private MyDragbar dragbar;
private double fraction;
public HorizontalSplitPane(JComponent comp0, JComponent comp1) {
this(comp0, comp1, 0.5);
}
public HorizontalSplitPane(JComponent comp0, JComponent comp1,
double fraction) {
this.rup0 = comp0;
this.rup1 = comp1;
this.dragbar = new MyDragbar(); // above the other components
this.fraction = fraction;
setLayout(new MyLayout());
add(dragbar); // above the other components
add(comp0);
add(comp1);
}
public double getFraction() {
return fraction;
}
public void setFraction(double value) {
if(value < 0.0) value = 0.0;
if(value > 1.0) value = 1.0;
if(fraction != value) {
fraction = value;
revalidate();
}
}
}
</source>
Panel with background image
<source lang="java">
import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JPanel; public class ImageTest {
public static void main(String[] args) {
ImagePanel panel = new ImagePanel(new ImageIcon("images/background.png").getImage());
JFrame frame = new JFrame();
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
}
} class ImagePanel extends JPanel {
private Image img;
public ImagePanel(String img) {
this(new ImageIcon(img).getImage());
}
public ImagePanel(Image img) {
this.img = img;
Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
setPreferredSize(size);
setMinimumSize(size);
setMaximumSize(size);
setSize(size);
setLayout(null);
}
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
}
</source>
Retrieve all components individually:
<source lang="java">
import java.awt.ruponent; import javax.swing.JFrame; public class Main {
public static void main(String[] argv) throws Exception {
JFrame container = new JFrame();
// Get number of children
int count = container.getComponentCount();
for (int i = 0; i < count; i++) {
Component c = container.getComponent(i);
}
}
}
</source>
