Code for Tree Model Example
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package com.trolltech.examples;
import com.trolltech.qt.core.*;
import com.trolltech.qt.gui.*;
import java.util.*;
@QtJambiExample(name = "A Jambi Tree Model")
public class TreeModel extends QTreeView
{
private static class Model extends QTreeModel {
public Model(QObject parent) {
super(parent);
}
/**
* Returns the number of children this parent has.
*/
@Override
public int childCount(Object parent) {
return entryList(dir(parent)).size();
}
/**
* Converts the parent to a QDir and accesses its entry list to
* create a new QDir as the child.
*/
@Override
public Object child(Object parent, int row) {
QDir d = dir(parent);
return new QDir(d.absoluteFilePath(entryList(d).get(row)));
}
/**
* Converts the directory to a QDir and returns it.
*/
@Override
public String text(Object value) {
return ((QDir) value).dirName();
}
/**
* Convenience method for getting the entry list of a
* directory. This method also caches the previous entry list, as
* the same entry list is often used again and again.
*/
private List<String> entryList(QDir dir) {
if (dir == lastDirectory) {
return lastEntryList;
}
lastEntryList = dir.entryList(entryListFlags);
lastDirectory = dir;
return lastEntryList;
}
/**
* Convenience method for converting the object to a QDir. If the
* value is null, its the root.
*/
private QDir dir(Object value) {
return value != null ? (QDir) value : QDir.root();
}
private QDir lastDirectory;
private List<String> lastEntryList;
private QDir.Filters entryListFlags = new QDir.Filters(QDir.Filter.NoDotAndDotDot,
QDir.Filter.Dirs,
QDir.Filter.Files);
}
public TreeModel() {
this(null);
}
public TreeModel(QWidget parent) {
// Hide my header...
header().hide();
// Create our jambi file model
Model model = new Model(this);
setModel(model);
show();
// The QTreeModel does some caching of datastructures
// behind the scenes. To avoid memory pooling of this
// datastructure we can call the releaseChildren method to
// release parts of this pool when its no longer needed. One
// such case is when the view collapses a subtree and it is no
// longer visible.
collapsed.connect(model, "releaseChildren(QModelIndex)");
setWindowTitle("A Qt Jambi Tree Model");
setWindowIcon(new QIcon("classpath:com/trolltech/images/qt-logo.png"));
}
public static void main(String args[]) {
QApplication.initialize(args);
// Create the tree view.
TreeModel view = new TreeModel();
view.show();
// Spin the event loop
QApplication.exec();
}
}
Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies) |
Trademarks |
Qt Jambi 4.5.2_01 |