Vaadin Web应用开发教程(19):UI组件-Tree 组件
上一篇:http://www.zzzyk.com/kf/201208/147765.htmlTree 组件可以用来显示具有层次关系的数据源,比如文件系统。Tree组件的一个典型应用是作为菜单显示。
[java]
final Object[][] planets = new Object[][]{
new Object[]{"Mercury"},
new Object[]{"Venus"},
new Object[]{"Earth", "The Moon"},
new Object[]{"Mars", "Phobos", "Deimos"},
new Object[]{"Jupiter", "Io", "Europa", "Ganymedes",
"Callisto"},
new Object[]{"Saturn", "Titan", "Tethys", "Dione",
"Rhea", "Iapetus"},
new Object[]{"Uranus", "Miranda", "Ariel", "Umbriel",
"Titania", "Oberon"},
new Object[]{"Neptune", "Triton", "Proteus", "Nereid",
"Larissa"}};
Tree tree = new Tree("The Planets and Major Moons");
// Add planets as root items in the tree.
for (int i=0; i String planet = (String) (planets[i][0]);
tree.addItem(planet);
if (planets[i].length == 1) {
// The planet has no moons so make it a leaf.
tree.setChildrenAllowed(planet, false);
} else {
// Add children (moons) under the planets.
for (int j=1; j String moon = (String) planets[i][j];
// Add the item as a regular item.
tree.addItem(moon);
// Set it to be a child.
tree.setParent(moon, planet);
// Make the moons look like leaves.
tree.setChildrenAllowed(moon, false);
}
// Expand the subtree.
tree.expandItemsRecursively(planet);
}
}
main.addComponent(tree);
final Object[][] planets = new Object[][]{
new Object[]{"Mercury"},
new Object[]{"Venus"},
new Object[]{"Earth", "The Moon"},
new Object[]{"Mars", "Phobos", "Deimos"},
new Object[]{"Jupiter", "Io", "Europa", "Ganymedes",
"Callisto"},
new Object[]{"Saturn", "Titan", "Tethys", "Dione",
"Rhea", "Iapetus"},
new Object[]{"Uranus", "Miranda", "Ariel", "Umbriel",
"Titania", "Oberon"},
new Object[]{"Neptune", "Triton", "Proteus", "Nereid",
"Larissa"}};
Tree tree = new Tree("The Planets and Major Moons");
// Add planets as root items in the tree.
for (int i=0; i String planet = (String) (planets[i][0]);
tree.addItem(planet);
if (planets[i].length == 1) {
// The planet has no moons so make it a leaf.
tree.setChildrenAllowed(planet, false);
} else {
// Add children (moons) under the planets.
for (int j=1; j String moon = (String) planets[i][j];
// Add the item as a regular item.
tree.addItem(moon);
// Set it to be a child.
tree.setParent(moon, planet);
// Make the moons look like leaves.
tree.setChildrenAllowed(moon, false);
}
// Expand the subtree.
tree.expandItemsRecursively(planet);
}
}
main.addComponent(tree);
当然你可以选择合适的Menu风格使得Tree看起来更像菜单,比如: