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Resize JList file elements in JFileChooser

I have a JFileChooser. I am trying to add a zoom feature to the files JList.
I would like to change the scale factor of the file name and of the file icon, for each element of the list.
How could we achieve this ?
Should I make a custom renderer like here [JList custom renderer example] (http://www.codejava.net/java-se/swing/jlist-custom-renderer-example)
or change the list Model ?

Well, I found out some ugly lazy hacks to do it.
It might not be just what you want, but it's a good starting point (and fairly simple):
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.plaf.basic.BasicListUI;
public class TJFileChooserDemo {
//Obtains the (first) JList which is found inside the component/container:
public static JList getFirstJList(final Component component) {
if (component instanceof JList)
return (JList) component;
if (component instanceof Container)
for (int i=0; i<((Container)component).getComponentCount(); ++i) {
final JList list = getFirstJList(((Container)component).getComponent(i));
if (list != null)
return list;
}
return null;
//As you can see, it's a bit lazy hack, which has to run for every JFileChooser once at start-up.
}
private static final double SCALE_STEP_SIZE = 0.125; //Smaller values of this makes zooming slower. Greater values makes zooming faster.
private static double scaleFactor = 1;
public static class TJListCellRenderer extends DefaultListCellRenderer {
public TJListCellRenderer() {
//Ensure every pixel is painted starting from the top-left corner of the label:
super.setVerticalAlignment(JLabel.TOP);
super.setHorizontalAlignment(JLabel.LEFT);
//We need to do this, because the scaling in paintComponent() is also relative to the top-left corner.
}
#Override
public void paintComponent(final Graphics g) {
//setRenderingHints here? Probably for ANTIALIAS...
((Graphics2D)g).scale(scaleFactor, scaleFactor); //Let's scale everything that is painted afterwards:
super.paintComponent(g); //Let's paint the (scaled) JLabel!
}
#Override
public Dimension getPreferredSize() {
final Dimension superPrefDim = super.getPreferredSize(); //Handles automatically insets, icon size, text font, etc.
final double w = superPrefDim.width * scaleFactor, //And we just scale the preferred size.
h = superPrefDim.height * scaleFactor; //And we just scale the preferred size.
return new Dimension((int)w + 5, (int)h + 5); //Add 5 extra pixels to spare.
}
#Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
// System.out.println(value.getClass()); //Something ugly...
return super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
}
}
public static class TJListUI extends BasicListUI {
#Override
public void updateLayoutState() {
super.updateLayoutState(); //Just make the following method public.
/*Note: this is not really needed here:
The method could remain protected, but in the case you want this
code to be a bit more reusable, then you shall make it public.*/
}
}
public static void main(final String[] args) {
final JFileChooser jfc = new JFileChooser();
jfc.setDialogType(JFileChooser.OPEN_DIALOG);
final TJListUI ui = new TJListUI();
final JList list = getFirstJList(jfc);
list.setUI(ui);
list.setCellRenderer(new TJListCellRenderer());
final JButton buttonZoomIn = new JButton("Zoom in"),
buttonZoomOut = new JButton("Zoom out"),
buttonResetZoom = new JButton("Reset zoom");
buttonZoomIn.addActionListener(e -> {
scaleFactor = scaleFactor + SCALE_STEP_SIZE;
ui.updateLayoutState(); //Read the preferred sizes from the cell renderer.
list.revalidate(); //Update the JScrollPane.
list.repaint(); //Repaint the list.
});
buttonZoomOut.addActionListener(e -> {
scaleFactor = Math.max(scaleFactor - SCALE_STEP_SIZE, SCALE_STEP_SIZE); //Do not allow underflow.
ui.updateLayoutState(); //Read the preferred sizes from the cell renderer.
list.revalidate(); //Update the JScrollPane.
list.repaint(); //Repaint the list.
});
buttonResetZoom.addActionListener(e -> {
scaleFactor = 1;
ui.updateLayoutState(); //Read the preferred sizes from the cell renderer.
list.revalidate(); //Update the JScrollPane.
list.repaint(); //Repaint the list.
});
final JPanel buttons = new JPanel(); //FlowLayout.
buttons.add(buttonZoomIn);
buttons.add(buttonZoomOut);
buttons.add(buttonResetZoom);
final JPanel panel = new JPanel(new BorderLayout());
panel.add(buttons, BorderLayout.PAGE_START);
panel.add(jfc, BorderLayout.CENTER);
final JFrame frame = new JFrame("JFileChooser's JList cell sizes demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
Alternatively you can check my answer here about individually resizable cells of a JList.
You can also probably add the JFileChooser's buttons for zooming in/out as an accessory. Read this simple example for how to do it.
Test this code, and I am waiting for comments...

In the end, I realized scaling the text wasn't needed.
To obtain the image files thumbnail, I used the code in making JFileChooser show image thumbnails - check BoffinbraiN answer.
Then for scaling :
1) add an ActionListener to the buttons of ThumbnailFileChooser.
public class ZoomListener implements ActionListener {
private boolean zoomIn = false;
private IconScaleManager iconScaleManager = null;
public ZoomListener(boolean zoom, IconScaleManager renderer) {
zoomIn = zoom;
iconScaleManager = renderer;
}
#Override
public void actionPerformed(ActionEvent e) {
iconScaleManager.scaleButton(zoomIn);
}
}
2) ActionListener::actionPerformed() calls a scale method of a ScaleManager.
#Override
public void actionPerformed(ActionEvent e) {
iconScaleManager.scaleButton(zoomIn);
}
3) The ScaleManager method changes and update the cells of the ThumbnailFileChooser's Jlist (the list is an attribute of the ScaleManager)
public class IconScaleManager {
static final int[] iconScales = new int[]{ 16, 32, 64, 128, 256, 512, 1024, 2048 };
private int scaleIndex = 4;
private JList fileList = null;
public IconScaleManager(JList list) {
fileList = list;
setFixedCellDimension();
}
public void scaleButton(boolean zoomIn) {
if (zoomIn && scaleIndex < iconScales.length - 1) {
scaleIndex++;
setFixedCellDimension();
} else if (!zoomIn && 0 < scaleIndex) {
scaleIndex--;
setFixedCellDimension();
}
}
private void setFixedCellDimension() {
fileList.setFixedCellWidth(iconScales[scaleIndex]);
fileList.setFixedCellHeight(iconScales[scaleIndex]);
}
}
Thank you #thanopi57 for your help. I didn't really use what you provided, but I appreciate your support.
Also, I will have to make sure that it works, because there might not be a JList for all JFileChooser

How To Define Table's Vertical Alignment

Incredible easy question: I have a SWT table (viewer) and use a SWT.MeasureItem listener to set the cell height. How do I align the cell content to the bottom of the cell?
(It would probably work with another listener to SWT.PaintItem and some math and rendering all my cells manually, but that can't be the right way.)
public class TableDialog extends Dialog {
public static void main(String[] args) {
TableDialog dialog = new TableDialog(new Shell());
dialog.open();
}
public TableDialog(Shell parent) {
super(parent);
}
#Override
protected void configureShell(Shell newShell) {
super.configureShell(newShell);
newShell.setText("Table Test");
newShell.setSize(500, 300);
}
#Override
protected Control createDialogArea(Composite parent) {
Composite container = (Composite) super.createDialogArea(parent);
container.setLayout(new FillLayout());
TableViewer viewer = new TableViewer(container, SWT.BORDER | SWT.FULL_SELECTION);
viewer.setContentProvider(new ArrayContentProvider());
viewer.setInput(Arrays.asList("A", "B", " C"));
Table table = viewer.getTable();
table.setLinesVisible(true);
table.addListener(SWT.MeasureItem, e -> e.height = 90);
return container;
}
}

Once you start using SWT.MeasureItem you need to do the drawing as well.
Since you are using TableViewer you can combine all this in one class by using an OwnerDrawLabelProvider as the viewer label provider. A very simple version would be something like this:
viewer.setLabelProvider(new OwnerDrawLabelProvider()
{
#Override
protected void paint(final Event event, final Object element)
{
String text = element.toString();
GC gc = event.gc;
int textHeight = gc.textExtent(text).y;
int yPos = event.y + event.height - textHeight;
gc.drawText(text, event.x, yPos);
}
#Override
protected void measure(final Event event, final Object element)
{
event.height = 90;
}
#Override
protected void erase(final Event event, final Object element)
{
// Stop the default draw of the foreground
event.detail &= ~SWT.FOREGROUND;
}
});

I am afraid, SWT.PaintItem is the right way in this case.
One of the SWT Snippets demonstrates how to draw multiple lines in a table item. It may serve as a starting point for your custom drawing code:
http://git.eclipse.org/c/platform/eclipse.platform.swt.git/tree/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet231.java
The Custom Drawing Table and Tree Items article provides further information.

how to add remove button in combobox

I would like to create a ComboBox with the remove button like the picture below:
The picture uses Java Swing, and I don't know how to do this with JavaFX. I would like to create two ComboBoxes (a,b). When I click the "cross" in ComboBox a, I would like to remove a's item and add this item to ComboBox b, and ComboBox b so on.
ComboBox a：
(1)click item then remove it from a and add on b
ComboBox b：
(1)click item then do something(ex:print item)
(2)click cross then remove it from b and add on a
package UnitTest;
import Peer.Peer_Manager;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.chart.XYChart;
import javafx.geometry.Insets;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Text;
public class temp extends Application {
final int height = 200;
final int weight = 300;
final int offset = 5;
Peer_Manager p_management;
XYChart.Series series_hop;
XYChart.Series series_gd;
#Override
public void start(Stage primaryStage) {
VBox vbox = new VBox();
vbox.setPadding(new Insets(5, 5, 5, 5));
vbox.setStyle("-fx-background-color: CORNSILK;");
Scene scene = new Scene(vbox, weight, height);
primaryStage.setScene(scene);
HBox hbBtn = new HBox();
Text t1=new Text(" A：");
Text t2=new Text(" B：");
String[] filename = {"A","B","C"};//conf.load_all();
ComboBox<String> cb = new ComboBox<String>();
cb.setItems(FXCollections.observableArrayList(filename));
cb.setVisibleRowCount(10);
ComboBox<String> cb2 = new ComboBox<String>();
cb.setVisibleRowCount(10);
vbox.getChildren().add(hbBtn);
hbBtn.getChildren().add(t1);
hbBtn.getChildren().add(cb);
hbBtn.getChildren().add(t2);
hbBtn.getChildren().add(cb2);
cb.setOnAction(e -> {
try {
Object object = cb.getValue();
if (object != null) {
cb2.getItems().add(object);
cb.getSelectionModel().clearSelection();
cb.getItems().remove(object);
}
} catch (Exception e1) {
e1.printStackTrace();
}
});
//would like to do something(ex:print item),but don't remove
//add the "cross" beside items,click "cross" to remove item and add on cb
cb2.setOnAction(e -> {
try {
Object object = cb2.getValue();
System.out.println(object);
if (object != null) {
cb1.getItems().add(object);
cb2.getSelectionModel().clearSelection();
cb2.getItems().remove(object);
}
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
});
primaryStage.setTitle("SimulatorFX");
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}

The correct way is to use a CellFactory and create graphic nodes that contain the elements you wish to have. Here is an example:
public void start(Stage primaryStage) throws Exception {
ComboBox<String> cba = new ComboBox<>();
ComboBox<String> cbb = new ComboBox<>();
cba.getItems().addAll("A", "B", "C");
cbb.getItems().addAll("123", "456", "789");
// Set a cell factory for ComboBox A. A similar thing should be done for B.
cba.setCellFactory(lv ->
new ListCell<String>() {
// This is the node that will display the text and the cross.
// I chose a hyperlink, but you can change to button, image, etc.
private HBox graphic;
// this is the constructor for the anonymous class.
{
Label label = new Label();
// Bind the label text to the item property. If your ComboBox items are not Strings you should use a converter.
label.textProperty().bind(itemProperty());
// Set max width to infinity so the cross is all the way to the right.
label.setMaxWidth(Double.POSITIVE_INFINITY);
// We have to modify the hiding behavior of the ComboBox to allow clicking on the hyperlink,
// so we need to hide the ComboBox when the label is clicked (item selected).
label.setOnMouseClicked(event -> cba.hide());
Hyperlink cross = new Hyperlink("X");
cross.setVisited(true); // So it is black, and not blue.
cross.setOnAction(event ->
{
// Since the ListView reuses cells, we need to get the item first, before making changes.
String item = getItem();
System.out.println("Clicked cross on " + item);
if (isSelected()) {
// Not entirely sure if this is needed.
cba.getSelectionModel().select(null);
}
// Remove the item from A and add to B. You can add any additional logic in here.
cba.getItems().remove(item);
cbb.getItems().add(item);
}
);
// Arrange controls in a HBox, and set display to graphic only (the text is included in the graphic in this implementation).
graphic = new HBox(label, cross);
graphic.setHgrow(label, Priority.ALWAYS);
setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
}
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
} else {
setGraphic(graphic);
}
}
});
// We have to set a custom skin, otherwise the ComboBox disappears before the click on the Hyperlink is registered.
cba.setSkin(new ComboBoxListViewSkin<String>(cba) {
#Override
protected boolean isHideOnClickEnabled() {
return false;
}
});
VBox vb = new VBox(cba, cbb);
primaryStage.setScene(new Scene(vb));
primaryStage.show();
}

Why does a fireContentsChanged call of a JList freezes the entire GUI?

I had some problems with freezing SWING GUIs when re-rendering a JTable with a custom cell renderer in Java. So I asked the question "Why does a JTable view update block the entire GUI?". The answers pointed to the fact, that a JList without modifying JTable and overwriting doLayout might be a better choice. So I implemented the example with a JList and ran into the same problem: while generating data, everything works fine and the progress bar moves. But when the view is updated, the program freezes and the progress bar stops moving.
Please note, that the sleep statement is there only to let the generation take a longer, more realistic time (reading thousands of data sets via JDBC and create objects out of them takes a lot time). One could remove it and increment the number of generated items. But you can clearly see, that the HTML rendering is quite slow. But I need this colors and the two lines (if not necessarily so many different colors).
So could you please tell me, where my mistake is? I think, that EDT and other work is separated through separate threads and I cannot see any mistke.
Update: I looked around at SO and found this question "https://stackoverflow.com/a/20813122/2429611". There is said:
The more interesting question would be how to avoid that UI blocking, but I don't think that's possible with just Swing, you'll have to implement some lazy loading, or rendering in batches.
This would mean, that I cannot solve my problem. Is this correct?
package example;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.AbstractListModel;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.SwingUtilities;
public class ListExample extends AbstractListModel {
static List<DemoObject> internalList = new ArrayList<>();
#Override
public int getSize() {
return internalList.size();
}
#Override
public DemoObject getElementAt(int index) {
return internalList.get(index);
}
public void fireContentsChanged() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
fireContentsChanged(this, 0, -1);
}
});
}
static class MyCellRenderer extends JLabel implements ListCellRenderer<ListExample.DemoObject> {
public MyCellRenderer() {
setOpaque(true);
}
#Override
public Component getListCellRendererComponent(JList<? extends ListExample.DemoObject> list,
ListExample.DemoObject value,
int index,
boolean isSelected,
boolean cellHasFocus) {
setText("<html>" + value.toString()
+ "<br/>"
+ "<span bgcolor=\"#ff0000\">Line 2; Color = " + value.c + "</span>");
Color background;
Color foreground;
// check if this cell represents the current DnD drop location
JList.DropLocation dropLocation = list.getDropLocation();
if (dropLocation != null
&& !dropLocation.isInsert()
&& dropLocation.getIndex() == index) {
background = Color.BLUE;
foreground = Color.WHITE;
// check if this cell is selected
} else if (isSelected) {
background = Color.RED;
foreground = Color.WHITE;
// unselected, and not the DnD drop location
} else {
background = value.c; //Color.WHITE;
foreground = Color.BLACK;
};
setBackground(background);
setForeground(foreground);
return this;
}
}
static class DemoObject {
String str;
Color c;
public DemoObject(String str, int color) {
this.str = str;
this.c = new Color(color);
}
#Override
public String toString() {
return str;
}
}
static JPanel overlay;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Example");
frame.setLayout(new BorderLayout(4, 4));
// Add JTable
final ListExample model = new ListExample();
JList list = new JList(model);
list.setCellRenderer(new MyCellRenderer());
frame.add(new JScrollPane(list), BorderLayout.CENTER);
// Add button
Box hBox = Box.createHorizontalBox();
hBox.add(new JButton(new AbstractAction("Load data") {
#Override
public void actionPerformed(ActionEvent e) {
new Thread(new Runnable() {
#Override
public void run() {
overlay.setVisible(true);
internalList.clear();
System.out.println("Generating data ...");
SecureRandom sr = new SecureRandom();
for (int i = 0; i < 10000; i++) {
internalList.add(
new DemoObject(
"String: " + i + " (" + sr.nextFloat() + ")",
sr.nextInt(0xffffff)
)
);
// To create the illusion, that data are
// fetched via JDBC (which takes a little
// while), this sleep statement is embedded
// here. In a real world scenario, this wait
// time is caused by talking to the database
// via network
if (i%10 == 0) {
try {
Thread.sleep(1);
} catch (Exception e) {
}
}
}
System.out.println("Updating view ...");
model.fireContentsChanged();
overlay.setVisible(false);
System.out.println("Finished.");
}
}).start();
}
}));
hBox.add(Box.createHorizontalGlue());
frame.add(hBox, BorderLayout.NORTH);
// Create loading overlay
overlay = new JPanel(new FlowLayout(FlowLayout.CENTER)) {
#Override
protected void paintComponent(Graphics g) {
g.setColor(new Color(0, 0, 0, 125));
g.fillRect(0, 0, getWidth(), getHeight());
super.paintComponent(g);
}
};
overlay.setOpaque(false);
overlay.setBackground(new Color(0, 0, 0, 125));
JProgressBar bar = new JProgressBar();
bar.setIndeterminate(true);
overlay.add(bar);
frame.setGlassPane(overlay);
frame.getGlassPane().setVisible(false);
// Create frame
frame.setSize(600, 400);
frame.setVisible(true);
}
});
}
}

there are three problems (recreating, reseting the model, and custom Renderer stoped to works)
JList (JComboBox hasn't) has an issue by removing more than 999 items, you have to set a new model to JList
see important for ComboBoxModel extends AbstractListModel implements MutableComboBoxModel for setElementAt(to hold current selection)
usage of public void fireContentsChanged() { is wrong, don't see reason to use this way, again is about to replace current, reset the model
. e.g. with success atr runtime and by recrusive testing for/if event (fired)
setModel(new DefaultListModel(list.toArray()) {
protected void fireContentsChanged(Object obj, int i, int j) {
if (!isFired)
super.fireContentsChanged(obj, i, j);
}
});

Manual Positioning of Image in JFrame

I am trying to create a JFrame that displays an image from a file path onto a particular position on the JFrame. At a later time (when a button is clicked), I want the image to move positions, say, 50 pixles to the left. If a layout manager is necessary, I want to use the null layout, as this is a project for myself and I am not quite ready to learn how to write my own layout manager.
So far, I have managed to display a BufferedImage in a frame, but I do not know how to specify its position.
Is using a BufferedImage even the correct approach? What is the best way to go about doing this?
Update: I tried to follow your suggestion of using mouselistener and it resulted in this:
class ImgComponent extends JComponent implements ChangeListener, MouseListener {
MovableImage mi;
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
mi.addListener1(this);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(mi.i, mi.getX(), mi.getY(), null);
}
#Override
public void stateChanged(ChangeEvent e) {
repaint();
}
#Override
public void mouseClicked(MouseEvent e) {
mi.setPos(100, 100);
System.out.println("yay");
}
}
But unfortinely, the mouseClicked event never triggers. I just want that damn image to move, lol.

Here's a complete example that uses the model/view/controller pattern. (Just dump all snippets after each other in a single .java file.)
import java.awt.*;
import java.awt.event.ActionEvent;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.event.*;
// A class encapsulating an image and a x-coordinate (a "model")
class MovableImage {
Image i = new ImageIcon("duke.png").getImage();
private int x = 0;
// Observers that are interested in movements.
List<ChangeListener> listeners = new ArrayList<ChangeListener>();
public void addListener(ChangeListener cl) {
listeners.add(cl);
}
public int getX() {
return x;
}
public void incrementX() {
x += 10;
// Notify those interested.
for (ChangeListener cl : listeners)
cl.stateChanged(null);
}
}
// A graphical component displaying the model.
// Object of this class are interested in movement because when the image moves,
// this component needs to be repainted.
class ImgComponent extends JComponent implements ChangeListener {
// The movable image to present.
MovableImage mi;
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(mi.i, mi.getX(), 10, null);
}
// This method is called from MovableImage when the position changes.
#Override
public void stateChanged(ChangeEvent e) {
repaint();
}
}
// Main class.
public class FrameTestBase extends JFrame {
public static void main(String args[]) {
// Create the "model".
final MovableImage mi = new MovableImage();
FrameTestBase t = new FrameTestBase();
t.setLayout(new BorderLayout());
// Add a component presenting the model.
t.add(new ImgComponent(mi), BorderLayout.CENTER);
// Create a button which increments x when clicked on.
t.add(new JButton(new AbstractAction("Move right") {
#Override
public void actionPerformed(ActionEvent e) {
mi.incrementX();
}
}), BorderLayout.SOUTH);
// Show it.
t.setDefaultCloseOperation(EXIT_ON_CLOSE);
t.setSize(400, 400);
t.setVisible(true);
}
}
Regarding your edit:
You need to add the mouse listener as well. In the constructor:
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
mi.addListener1(this);
}
add the following line at the bottom:
addMouseListener(this);