Datei auswählen und zeilenweise darstellen

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1 Bereich: Grafische Benutzeroberflächen (UI) (2) Datei auswählen und zeilenweise darstellen Package: de.dhbwka.java.exercise.ui Musterlösung Klasse: TextfileViewer Variante 1 (Labels): import java.awt.gridlayout; import java.io.bufferedreader; import java.io.file; import java.io.filereader; import java.io.ioexception; import javax.swing.jfilechooser; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.joptionpane; import javax.swing.filechooser.filefilter; DHBW 1.0 Part of lectures on 'Programming in Java'. Baden-Wuerttemberg Cooperative State University. (C) 2016 by W. Geiger, T. Schlachter, C. Schmitt, W. Suess / public class TextfileViewer { private static final int MAX_LINES = 10; public TextfileViewer(File file) { JFrame frame = new JFrame(file.getName()); String[] content = readtextfile(file); final int displaylines = Math.min(content.length, MAX_LINES); frame.setlayout(new GridLayout(displayLines,1)); for (int i = 0; i<displaylines; i++) { frame.add(new JLabel(content[i])); frame.setdefaultcloseoperation(jframe.exit_on_close); frame.setsize(640, 480); frame.setvisible(true);

2 / Read Textfile f and return its content as an Array of Strings / public static String[] readtextfile(file f) { int lines = 0; // Count lines first try (BufferedReader br = new BufferedReader(new FileReader(f))) { while (br.ready()) { br.readline(); lines++; catch (IOException e) { e.printstacktrace(); // ToDo: nice error handling String[] result = new String[lines]; lines = 0; try (BufferedReader br = new BufferedReader(new FileReader(f))) { while (br.ready()) { result[lines++] = br.readline(); catch (IOException e) { e.printstacktrace(); // ToDo: nice error handling return result; // FileChooser as presented in slides "Swing" JFileChooser fc = new JFileChooser(); fc.setfilefilter(new FileFilter() { public boolean accept(file f) { return f.isdirectory() f.getname().tolowercase().endswith(".txt"); public String getdescription() { return "Texte"; ); int state = fc.showopendialog(null); if (state == JFileChooser.APPROVE_OPTION) new TextfileViewer(fc.getSelectedFile()); else JOptionPane.showMessageDialog(null, "Auswahl abgebrochen");

3 Variante 2 (TextArea): import java.awt.borderlayout; import java.io.file; import javax.swing.; import javax.swing.filechooser.filefilter; DHBW 1.0 Part of lectures on 'Programming in Java'. Baden-Wuerttemberg Cooperative State University. (C) 2016 by W. Geiger, T. Schlachter, C. Schmitt, W. Suess / public class TextfileViewer2 { public TextfileViewer2(File file) { JFrame frame = new JFrame(file.getName()); frame.setlayout(new BorderLayout()); StringBuilder joinedcontent = new StringBuilder(); for (String s : TextfileViewer.readTextfile(file)) { joinedcontent.append(s).append(system.lineseparator()); JScrollPane scrollpane = new JScrollPane( new JTextArea(joinedContent.toString())); frame.add(scrollpane,borderlayout.center); frame.setdefaultcloseoperation(jframe.exit_on_close); frame.setsize(640, 480); frame.setvisible(true); // FileChooser as presented in slides "Swing" JFileChooser fc = new JFileChooser(); fc.setfilefilter(new FileFilter() { public boolean accept(file f) { return f.isdirectory() f.getname().tolowercase().endswith(".txt"); public String getdescription() { return "Texte"; ); int state = fc.showopendialog(null); if (state == JFileChooser.APPROVE_OPTION) new TextfileViewer2(fc.getSelectedFile()); else JOptionPane.showMessageDialog(null, "Auswahl abgebrochen");

4 Bereich: Grafische Benutzeroberflächen (UI) (2) Währungsumrechner Package: de.dhbwka.java.exercise.ui Musterlösung Klasse: CurrencyCalculator import java.awt.borderlayout; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jtextfield; DHBW 1.0 Part of lectures on 'Programming in Java'. Baden-Wuerttemberg Cooperative State University. (C) 2016 by W. Geiger, T. Schlachter, C. Schmitt, W. Suess / public class CurrencyCalculator { public final float CHANGE_RATE = 1.14f; private JFrame f = new JFrame("Währungsumrechner");; private JTextField input = new JTextField( "Bitte hier Betrag zum Umrechnen eingeben!"); private JButton eur2usdbt = new JButton("EUR -> USD"); private JButton usd2eurbt = new JButton("USD -> EUR"); private JButton cancelbt = new JButton("Abbrechen"); public CurrencyCalculator() { f.setdefaultcloseoperation(jframe.exit_on_close); f.setlayout(new BorderLayout(10, 10)); f.add(input, BorderLayout.NORTH); f.add(eur2usdbt, BorderLayout.WEST); f.add(usd2eurbt,borderlayout.center); f.add(cancelbt, BorderLayout.EAST); f.setsize(350, 90); f.setvisible(true); new CurrencyCalculator();

5 Bereich: Grafische Benutzeroberflächen (UI) (2) Editor Package: de.dhbwka.java.exercise.ui Musterlösung Klasse: EditorSimple import java.awt.borderlayout; import java.awt.font; import java.awt.event.keyevent; import javax.swing.jeditorpane; import javax.swing.jframe; import javax.swing.jmenu; import javax.swing.jmenubar; import javax.swing.jmenuitem; import javax.swing.jscrollpane; import javax.swing.jseparator; public class EditorSimple { private static final String SEPARATOR = "--"; private static final String SEND_MENU = "-SENDMENU-"; private final int INITIAL_WIDTH = 600; private final int INITIAL_HEIGHT = 480; private JFrame frame; private JMenu filemenu; private JMenu editmenu; private JEditorPane editpane; private final String[] filemenuitems = { "Neu", "Öffnen", SEPARATOR, "Schließen", SEPARATOR, "Speichern", "Speichern unter...", "Als Webseite speichern", "Suchen", SEPARATOR, "Versionen", SEPARATOR, "Webseitenvorschau", SEPARATOR, "Seite einrichten...", "Seitenansicht", "Drucken", SEPARATOR, SEND_MENU, "Eigenschaften", SEPARATOR, "bilanz_2007.doc", "quatalsbericht_2008_01.doc", "ziele.doc", SEPARATOR, "Beenden" ; private final String[] editmenuitems = { "Rückgängig", "Wiederholen", SEPARATOR, "Ausschneiden", "Kopieren", "Office-Zwischenablage", "Einfügen", "Inhalte einfügen", "Als Hyperlink einfügen", SEPARATOR, "Löschen", "Alles markieren", SEPARATOR, "Suchen...", "Ersetzen...", "Gehe zu...", SEPARATOR, "Verknüpfungen...", "Objekt" ; private final String[] sendmenuitems = { " -Empfänger", " -Empfänger (zur Überarbeitung)", " -Empfänger (als Anlage)", SEPARATOR, "Verteilerempfänger...", "Onlinebesprechungsteilnehmer", "Exchange-Ordner...", "Fax-Empfänger...", SEPARATOR, "Microsoft Powerpoint" ;

6 / Constructor for the editor / EditorSimple() { frame = new JFrame("Editor"); frame.setsize(initial_width, INITIAL_HEIGHT); frame.setlayout(new BorderLayout()); // Arbeitsfläche mit Scrollbalken erzeugen editpane = new JEditorPane(); editpane.setfont(new Font("Courier New", Font.PLAIN, 12)); frame.add(new JScrollPane(editPane), BorderLayout.CENTER); // Menü erzeugen JMenuBar menu = new JMenuBar(); menu.add(filemenu = getmenu("datei", KeyEvent.VK_D, filemenuitems)); menu.add(editmenu = getmenu("bearbeiten", KeyEvent.VK_B, editmenuitems)); frame.setjmenubar(menu); frame.setdefaultcloseoperation(jframe.exit_on_close); frame.setvisible(true); / Produces a JMenu with JMenuItems according to items-array / private JMenu getmenu(string menuname, int mnemonic, String[] items) { JMenu menu = new JMenu(menuName); menu.setmnemonic(mnemonic); for (String menuitemname : items) { switch (menuitemname) { case SEPARATOR : menu.add(new JSeparator()); break; case SEND_MENU : menu.add(getmenu("senden an", KeyEvent.VK_S, sendmenuitems)); break; default : menu.add(new JMenuItem(menuItemName)); return menu; / Run an instance of the editor / new EditorSimple();