Tree Example
This section illustrates you how to get the files from the available
directories and create a tree.
SWT provides a class Tree to represent the data in the hierarchical way and
TreeItem to represents the hierarchy of tree items in a tree by adding an
item to the tree.
In the given example, we are creating a tree which represents the
hierarchical structure of available files in the directories. The class File performs all the operations of the files and directories. The
method listRoots() provides the list of available file system roots. The method
listFiles() returns an array of file paths. The method getName() returns
the name of the file. In order to find whether the file is directory, we have
used the method isDirectory().
The class TreeItem adds the item to the tree by the method setText() and
setData(). The method getItems() returns an array of TreeItems. The method
getData() returns the data of the particular file.
Here is the code of TreeExample.java
import java.io.File;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.TreeItem;
public class TreeExample {
public static void main(String[] args) {
int w,h;
Display display = new Display();
Shell shell = new Shell(display);
shell.setText("Show Tree");
shell.setLayout(new FillLayout());
Tree tree = new Tree(shell, SWT.BORDER);
File[] file = File.listRoots();
for (int i = 0; i < file.length; i++) {
TreeItem item = new TreeItem(tree, 0);
item.setText(file[i].toString());
item.setData(file[i]);
new TreeItem(item, 0);
}
tree.addListener(SWT.Expand, new Listener() {
public void handleEvent(Event event) {
TreeItem item1 = (TreeItem) event.item;
TreeItem[] items = item1.getItems();
for (int i = 0; i < items.length; i++) {
if (items[i].getData() != null)
return;
items[i].dispose();
}
File file = (File) item1.getData();
File[] files = file.listFiles();
if (files == null)
return;
for (int i = 0; i < files.length; i++) {
TreeItem item2 = new TreeItem(item1, 0);
item2.setText(files[i].getName());
item2.setData(files[i]);
if (files[i].isDirectory()) {
new TreeItem(item2, 0);
}
}
}
});
shell.setSize(200,250);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
}
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