Atrus Greyor

How would I/is there any way to let the user select a file from my Application? For example, I'm making a book reading app, so I'd like to let the user be able to select an appropriate file. Is there any guaranteed way to give the user this ability?

Thank for the help.

Ah, okay. I wasn't aware that it created a new Graphics2D object, thank you very much.

With the following code, I'm unable to get an image to display the given character...

import java.awt.Font; import java.awt.font.FontRenderContext; import java.awt.geom.Rectangle2D; import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public class ImageWrite { public ImageWrite(Character c) { Font f = new Font(Font.MONOSPACED, Font.PLAIN, 24); BufferedImage img = new BufferedImage(1, 1, BufferedImage.TYPE_4BYTE_ABGR); img.getGraphics().setFont(f); FontRenderContext frc = img.getGraphics().getFontMetrics().getFontRenderContext(); Rectangle2D rect = f.getStringBounds(c.toString(), frc); img = new BufferedImage((int)Math.ceil(rect.getWidth()), (int)Math.ceil(rect.getHeight()), BufferedImage.TYPE_4BYTE_ABGR); img.getGraphics().setColor(Color.BLUE); img.getGraphics().setFont(f); img.getGraphics().drawString(c.toString(), 0, 0); try { ImageIO.write(img, "png", new File("image.png")); } catch(Exception e) { } } public static void main(String args[]) { new ImageWrite('#'); } }

What exactly am I doing wrong?

I apparently wasn't sure of my question either. Thanks for helping to point me in the correct direction though.

What's hanging me up with that is I would like the column to display both ImageIcons and Strings. So I don't think that the "getColumnClass" is the right way to go. Unless it needs to be written in a way that I'm just not seeing.

How exactly did you use the DefaultTableModel? I did it like the below, and I still only saw the path to the image.

import java.awt.Color; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.DefaultTableModel; import util.leveleditor.components.LETableModel; public class JRTest { public static void main(String args[]) { Object[][] datal = new Object[30][30]; Object[] titles = new Object[30]; for(int i = 0; i < datal.length; i++) { for(int j = 0; j < datal[i].length; j++) { datal[i][j] = new ImageIcon(JRTest.class.getResource("/resources/blankCell.png")); } } JTable data = new JTable(new DefaultTableModel(datal, titles)); data.setFillsViewportHeight(true); data.setAutoResizeMode(JTable.AUTO_RESIZE_OFF); data.setShowGrid(true); data.setGridColor(Color.BLACK); data.setTableHeader(null); JFrame frame = new JFrame("Test"); frame.add(new JScrollPane(data)); data.setValueAt("Moo", 1, 1); frame.pack(); frame.setVisible(true); } }

Okay, I see what my problem is, but, I'm not exactly sure how to fix it.

With the below, it imports correctly, however the images do not display correctly, showing their filename instead of the actual image:

import java.awt.Color; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import util.leveleditor.components.LETableModel; public class JRTest { public static void main(String args[]) { Object[][] datal = new Object[30][30]; Object[] titles = new Object[30]; for(int i = 0; i < datal.length; i++) { for(int j = 0; j < datal[i].length; j++) { datal[i][j] = new ImageIcon(JRTest.class.getResource("/resources/blankCell.png")); } } LETableModel model = new LETableModel(datal, titles); JTable data = new JTable(model); data.setFillsViewportHeight(true); data.setAutoResizeMode(JTable.AUTO_RESIZE_OFF); data.setShowGrid(true); data.setGridColor(Color.BLACK); data.setTableHeader(null); JFrame frame = new JFrame("Test"); frame.add(new JScrollPane(data)); data.setValueAt("Moo", 1, 1); frame.pack(); frame.setVisible(true); } }

I learned before that for the JTable to properly display ImageIcons, you need to add the getColumnClass method to the table. Which I did.

import java.awt.Color; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import util.leveleditor.components.LETableModel; public class JRTest { public static void main(String args[]) { Object[][] datal = new Object[30][30]; Object[] titles = new Object[30]; for(int i = 0; i < datal.length; i++) { for(int j = 0; j < datal[i].length; j++) { datal[i][j] = new ImageIcon(JRTest.class.getResource("/resources/blankCell.png")); } } LETableModel model = new LETableModel(datal, titles); JTable data = new JTable(model){ public Class getColumnClass(int column) { return getValueAt(0, column).getClass(); } }; data.setFillsViewportHeight(true); data.setAutoResizeMode(JTable.AUTO_RESIZE_OFF); data.setShowGrid(true); data.setGridColor(Color.BLACK); data.setTableHeader(null); JFrame frame = new JFrame("Test"); frame.add(new JScrollPane(data)); data.setValueAt("Moo", 1, 1); frame.pack(); frame.setVisible(true); } }

This is where the problem lies, and where you have to double click to see "Moo".

Here is my TableModel:

package util.leveleditor.components; import java.awt.Image; import java.util.Vector; import javax.swing.ImageIcon; import javax.swing.JLabel; import javax.swing.table.DefaultTableModel; public class LETableModel extends DefaultTableModel { public LETableModel() { super(); } public LETableModel(Object[][] a, Object[] b) { super(a, b); } public Vector getColumnIdentifiers() { return columnIdentifiers; } }

There isn't anything special. I don't modify the "setValueAt()" at all. However it does extend DefaultTableModel instead of AbstractTableModel

I'm using the basic JTable.

If my JTable is named data, and I call:

data.setValueAt("Moo", 1, 1);

The String is inserted, however, it's not visible unless I double click on the cell. How do I modify the cell so that it will appear without me having to double click?

Thanks,
Atrus.

Is any other information needed to help answer this question, I'm really stumped.

Matthew Cox wrote:You can't cast to it at Compile time if I am understanding your question correctly. When using Reflection, you are essentially giving up compile-time type checking and all the conveniences that come with it in order to gain the ability to "dynamically cast" as people seem to always describe it. Read up on Reflection and examine some coding examples. Reflection is tedious, run-time error prone (if not carefully coded), and if I remember correctly ... has a lot of overhead associated with it (not sure on this one). So be careful about how and when you decide to use it.

Someone in an earlier post mentioned a much simplier design ... it won't scale well but if you are only handling 4 or 5 classes and interfaces tops ... then creating a switch block of if block and using instanceof would be the best (meaning easiest) route. =D

GL

It's hard to do an if tree when the only information you have about the class is that it is a child of Z. It could be a class named A, B or something completely random.

However, I was able to solve it through reflection, thanks a lot Henry.

And then how would I go and cast that? I haven't ever used reflection, at least not knowingly.

I'm trying to implement D&D so that I am able to drag items from a JList. The JList contains either text or images, and I want the image to appear in the cell. My problems are:

When I try to drag a text element, and drop it, a white square appears. If I double click on the cell, I can see the text element.

When I try to drag an image element, I can't. It won't even let me. It comes from the same list as my text elements, so I don't understand why I can drag items in the list that only have text, but not ones that only have an image.

Here is my TransferHandler....

package util.leveleditor; import java.awt.Image; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.StringSelection; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.io.IOException; import javax.swing.JComponent; import javax.swing.JList; import javax.swing.JTable; import javax.swing.TransferHandler; import util.leveleditor.components.LETable; import util.leveleditor.components.LETableModel; public class LETransferHandler extends TransferHandler { private JTable data; public LETransferHandler() { } public void setTable(JTable tab) { data = tab; } public int getSourceActions(JComponent c) { return COPY; } public Transferable createTransferable(JComponent c) { JList list = (JList)c; if(list.getSelectedValue() instanceof Image) { return new ImageSelection((Image)list.getSelectedValue()); } else if(list.getSelectedValue() instanceof String) { return new StringSelection((String)list.getSelectedValue()); } return null; } public void exportDone(JComponent c, Transferable t, int action){} //For shits and giggles. public boolean canImport(TransferHandler.TransferSupport ts) { if(ts.isDataFlavorSupported(DataFlavor.imageFlavor)) return true; if(ts.isDataFlavorSupported(DataFlavor.stringFlavor)) return true; else return false; } public boolean importData(TransferHandler.TransferSupport ts) { JTable.DropLocation drop = (JTable.DropLocation)ts.getDropLocation(); LETableModel let = (LETableModel)data.getModel(); try { if(ts.getTransferable().isDataFlavorSupported(DataFlavor.stringFlavor)) { let.setValueAt(ts.getTransferable().getTransferData(DataFlavor.stringFlavor), drop.getRow(), drop.getColumn()); } else if(ts.getTransferable().isDataFlavorSupported(DataFlavor.imageFlavor)) { let.setValueAt(ts.getTransferable().getTransferData(DataFlavor.imageFlavor), drop.getRow(), drop.getColumn()); } } catch (UnsupportedFlavorException e) { return false; } catch (IOException e) { return false; } return true; } private class ImageSelection implements Transferable { private Image data = null; public ImageSelection(Image i) { data = i; } @Override public Object getTransferData(DataFlavor d) throws UnsupportedFlavorException, IOException { return data; } @Override public DataFlavor[] getTransferDataFlavors() { DataFlavor[] r = {DataFlavor.imageFlavor}; return r; } @Override public boolean isDataFlavorSupported(DataFlavor d) { return d.equals(DataFlavor.imageFlavor); } } }

What if I know that the class is a subclass of Z, but I don't know the name of the class itself?

For example I have class A, B, C and D all of which extend Z

Now I have ArrayList<Z> list = new ArrayList<Z>()

I've put several objects of type A, B, C and D in the list, randomly, and I don't know anything about the order.

How do I pull these items out with the correct type?