Informatik II. // ActionListener hinzufügen btnconvert.addactionlistener(this); super.setdefaultcloseoperation(jframe.

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1 Universität Augsburg, Institut für Informatik Sommersemester 2006 Prof. Dr. Werner Kießling 20. Juli M. Endres, A. Huhn, T. Preisinger Lösungsblatt 11 Aufgabe 1: Währungsrechner CurrencyConverter.java import java.awt.*; import java.awt.event.*; import java.io.*; import java.net.*; import java.text.numberformat; import java.util.*; import javax.swing.*; Informatik II public class CurrencyConverter extends JFrame implements ActionListener { final Currency EUR = new Currency("EUR", 1.0); JComboBox cbcurrfrom, cbcurrto; JTextField tfamountfrom = new JTextField(10); JLabel lblamountto = new JLabel(); JButton btnconvert = new JButton("Umrechnen"); NumberFormat formatter = NumberFormat.getInstance(); public CurrencyConverter() { super("währungsrechner"); formatter.setminimumfractiondigits(2); formatter.setmaximumfractiondigits(2); // Komponenenten erzeugen Currency[] curr = getcurrencies(); cbcurrfrom = new JComboBox(curr); cbcurrto = new JComboBox(curr); // ActionListener hinzufügen btnconvert.addactionlistener(this); super.setdefaultcloseoperation(jframe.exit_on_close); // Oberfläche zusammenstellen JComponent cp = (JComponent) getcontentpane(); cp.setlayout(new GridBagLayout()); cp.add(tfamountfrom, new GridBagConstraints(0, 0, 1, 1, 1.0, 0.0, new Insets(5, 5, 5, 5), 0, 0)); cp.add(cbcurrfrom, new GridBagConstraints(1, 0, 1, 1, 1.0, 0.0, new Insets(5, 0, 5, 5), 0, 0)); cp.add(new JLabel("in"), new GridBagConstraints(0, 1, 1, 1, 0.0, 0.0, GridBagConstraints.LINE_END, GridBagConstraints.NONE, new Insets(0, 5, 5, 5), 0, 0)); cp.add(cbcurrto, new GridBagConstraints(1, 1, 1, 1, 1.0, 0.0, cp.add(btnconvert, new GridBagConstraints(2, 1, 1, 1, 0.0, 0.0, GridBagConstraints.FIRST_LINE_START, GridBagConstraints.NONE, 1

2 cp.add(new JLabel("Ergebnis:"), new GridBagConstraints(0, 2, 1, 1, 1.0, 0.0, GridBagConstraints.LINE_END, GridBagConstraints.NONE, new Insets(0, 5, 5, 5), 0, 0)); cp.add(lblamountto, new GridBagConstraints(1, 2, 2, 1, 0.0, 0.0, GridBagConstraints.FIRST_LINE_START, GridBagConstraints.NONE, pack(); public static void main(string[] args) { new CurrencyConverter().setVisible(true); public Currency[] getcurrencies() { // Ohne Stream Currency[] result = new Currency[] { EUR, new Currency("USD", 1.279), new Currency("CHF", ), new Currency("GBP", ) ; // Mit Stream Vector<Currency> curr = new Vector<Currency>(); curr.add(eur); try { URL url = new URL( " URLConnection con = url.openconnection(); BufferedReader in = new BufferedReader(new InputStreamReader( con.getinputstream())); String line; while ((line = in.readline())!= null) { StringTokenizer tokens = new StringTokenizer(line, " "); int count = tokens.counttokens(); // 1. Token: <Cube currency= String first = tokens.nexttoken(); if (first.endswith("<cube currency=") && count == 5) { // 2. Token: Währungsname String name = tokens.nexttoken(); // 3. Token: rate= tokens.nextelement(); // 4. Token: Umrechnungsfaktor double factor = Double.parseDouble(tokens.nextToken()); curr.add(new Currency(name, factor)); in.close(); result = new Currency[curr.size()]; curr.copyinto(result); catch (IOException ioe) {; return result; public void actionperformed(actionevent e) { double amount = 0; try { amount = Double.parseDouble(tfAmountFrom.getText().replace(,,. )); // Umrechnung immer Quell-Währung zu Euro und dann // Euro zu Zielwährung 2

3 double toeur = ((Currency) cbcurrfrom.getselecteditem()).gettoeur(); double toresult = ((Currency) cbcurrto.getselecteditem()).gettoeur(); double result = amount / toeur * toresult; lblamountto.settext(formatter.format(result)); catch (NumberFormatException nfe) { JOptionPane.showMessageDialog(this, "Keine Zahl!", "Fehler", JOptionPane.ERROR_MESSAGE); class Currency { // Währungs-Kürzel final String name; // Umrechnung zu 1,00 EUR double rateeur; public Currency(String name, double rateeur) { this.name = name; this.rateeur = rateeur; public String getname() { return name; public double gettoeur() { return rateeur; public String tostring() { return name; Aufgabe 2: Datei-Explorer FileExplorer.java import java.awt.*; import java.io.file; import java.util.*; import javax.swing.*; import javax.swing.border.emptyborder; import javax.swing.event.*; import javax.swing.tree.*; public class FileExplorer extends JFrame { JTree tree; JTextArea list = new JTextArea(); JCheckBox chfile = new JCheckBox("Datei"); JCheckBox chdir = new JCheckBox("Verzeichnis"); JCheckBox chhidden = new JCheckBox("versteckt"); JCheckBox chreadable = new JCheckBox("lesbar"); JCheckBox chreadonly = new JCheckBox("schreibgeschützt"); public FileExplorer(File file) { super("file Explorer"); setdefaultcloseoperation(exit_on_close); tree = new JTree(new DirectoryTreeNode(file)); //tree = new JTree(new DirectoryTreeNode(new File("C:\\"))); tree.addtreeselectionlistener(new TreeSelectionListener() { public void valuechanged(treeselectionevent e) { TreePath path = tree.getselectionpath(); DirectoryTreeNode selection = (DirectoryTreeNode) path.getlastpathcomponent(); 3

4 ); if (selection.isleaf()) list.settext(""); else { // Verzeichnis: enthaltene Dateien in der Liste anzeigen StringBuffer sb = new StringBuffer(); Enumeration<DirectoryTreeNode> elements = selection.children(); while (elements.hasmoreelements()) { sb.append(elements.nextelement().tostring()); sb.append( \n ); list.settext(sb.tostring()); // CheckBoxen markieren File curfile = selection.getfile(); chhidden.setselected(curfile.ishidden()); chfile.setselected(curfile.isfile()); chdir.setselected(curfile.isdirectory()); chreadonly.setselected(curfile.canwrite()); chreadable.setselected(curfile.canread()); ButtonGroup bg = new ButtonGroup(); bg.add(chfile); bg.add(chdir); chhidden.setenabled(false); chreadable.setenabled(false); chreadonly.setenabled(false); chfile.setenabled(false); chdir.setenabled(false); list.seteditable(false); JComponent cp = (JComponent) getcontentpane(); cp.setborder(new EmptyBorder(5,5,5,5)); cp.add(new JScrollPane(tree), BorderLayout.LINE_START); JPanel pnlright = new JPanel(new BorderLayout()); JPanel pnlattributes = new JPanel(); pnlattributes.setlayout(new GridLayout(0, 1)); pnlattributes.add(chhidden); pnlattributes.add(chreadable); pnlattributes.add(chreadonly); pnlattributes.add(new JLabel(" Typ: ")); pnlattributes.add(chfile); pnlattributes.add(chdir); pnlattributes.add(new JLabel(" Inhalt: ")); pnlright.add(pnlattributes, BorderLayout.PAGE_START); pnlright.add(new JScrollPane(list), BorderLayout.CENTER); cp.setlayout(new BorderLayout()); cp.add(new JScrollPane(tree), BorderLayout.LINE_START); cp.add(pnlright, BorderLayout.CENTER); pack(); public static void main(string[] args) { new FileExplorer(new File(".")).setVisible(true); 4

5 class DirectoryTreeNode implements TreeNode { File file; public DirectoryTreeNode(File file) { this.file = file; public File getfile() { return file; // Enthaltene Datei an bestimmter Stelle zurückgeben public DirectoryTreeNode getchildat(int childindex) { return new DirectoryTreeNode(file.listFiles()[childIndex]); // Anzahl enthaltener Dateien public int getchildcount() { File[] children = file.listfiles(); return children!= null? children.length : 0; // Übergeordnetes Verzeichnis zurückliefern public DirectoryTreeNode getparent() { return new DirectoryTreeNode(file.getParentFile()); public int getindex(treenode node) { // Knoten suchen if (!(node instanceof DirectoryTreeNode)) { // falscher Typ des Knotens return -1; File obj = ((DirectoryTreeNode) node).getfile(); for (int i = 0; i < file.listfiles().length; i++) { if (file.equals(obj)) return i; return -1; // Verzeichnisse können "Kinder" haben public boolean getallowschildren() { return file.isdirectory(); // Eine einfache Datei ist ein Blatt public boolean isleaf() { return file.isfile(); public Enumeration<DirectoryTreeNode> children() { Vector<DirectoryTreeNode> dir = new Vector<DirectoryTreeNode>(); for (File elem : file.listfiles()) { dir.add(new DirectoryTreeNode(elem)); return dir.elements(); public String tostring() { return file.getname(); 5