main.java.bak

这是《Java 2 简明教程(第2版)》一书配套的源代码。

//public String getDirectory()
//public void setDirectory(String dir)
//public String getFile()
//public void setFile(String File)
//public FilenameFilter getFilenameFilter()
//public void setFilenameFilter(FilenameFilter filter)
//public init getMode()
//public init setMode()


import java.awt.*;
import java.io.*; 


class Main extends Frame implements FilenameFilter {
    FileDialog fd;
    TextField tfDirectory = new TextField();
    TextField tfFile = new TextField();
    TextField tfFilter = new TextField();

    Main() {
        super("FileDialog Example");
        add("West", new Button("Load"));
        add("East", new Button("Save"));

        Panel p = new Panel();
        p.setLayout(new GridBagLayout());
        addRow(p, new Label("directory:", Label.RIGHT), tfDirectory);
        addRow(p, new Label("file:", Label.RIGHT), tfFile);
        addRow(p, new Label("filter:", Label.RIGHT), tfFilter);

        add("South", p);
        pack();
        show();
    }

    // Adds a row in a gridbag layout where the c2 is stretchy
    // and c1 is not.
    void addRow(Container cont, Component c1, Component c2) {
        GridBagLayout gbl = (GridBagLayout)cont.getLayout();
        GridBagConstraints c = new GridBagConstraints();
        Component comp;

        c.fill = GridBagConstraints.BOTH;
        cont.add(c1);
        gbl.setConstraints(c1, c);

        c.gridwidth = GridBagConstraints.REMAINDER;
        c.weightx = 1.0;
        cont.add(c2);
        gbl.setConstraints(c2, c);
    }

    public boolean accept(File dir, String name) {
        if (fd.getMode() == FileDialog.LOAD) {
            return name.lastIndexOf(tfFilter.getText()) > 0;
        }
        return true;
    }

    public boolean action(Event evt, Object what) {
        boolean load = "Load".equals(what);

        if (load || "Save".equals(what)) {
            FileDialog fd = new FileDialog(this, null,
                load ? FileDialog.LOAD : FileDialog.SAVE);
            fd.setDirectory(tfDirectory.getText());
            fd.setFile(tfFile.getText());
            fd.setFilenameFilter(this);
            fd.show();
            tfDirectory.setText(fd.getDirectory());
            tfFile.setText(fd.getFile());
            
            // Filter must be the same
            if (fd.getFilenameFilter() != this) {
                throw new RuntimeException("Internal error");
            }
            return true;
        }
        return false;
    }

    static public void main(String[] args) {
        new Main();
    }
}