具有相同边界的java JTree子节点
我有一个带有自定义模型和自定义渲染器的JTree。它们似乎工作得很好,只是当我展开一个有多个子节点的节点时,它会将所有子节点绘制到同一个矩形中,因此只有最后一个节点可见。我可以遍历子节点,并将它们打印到控制台,但UI是不同的
这是UI的草图:
// for 1 child node:
ROOT
-- <rendered node>
//for 2 child nodes:
ROOT
|
-- <rendered node - the data of the 2nd node>
//for 3 child nodes:
ROOT
|
|
-- <rendered node - the data of the 3rd node>
我发现BasicTreeUI使用getPathBounds()来确定某个节点的边界。下面是我检查它的方式:
doStuffWithTree(JTree tree) {
tree.expandNode(0);
for (int i = 0; i < tree.getRowCount(); i++) {
TreePath tp = tree.getPathForRow(i);
tree.makeVisible(tp);
System.out.println("Bounds of row " + i + ": " + tree.getPathBounds(tp));
}
}
通过这个检查,我得到所有节点——除了节点0——都有相同的边界
我尝试了一些扩展树的技巧,例如从第一个节点开始扩展所有节点;然后从最后一个开始——它们都有相同的效果
最后,问题是:我可以修改什么类来修复这种行为?有什么已知的解决办法吗
更新
显然,TreeNode的实现需要解决一些问题。此外,我需要纠正自己:我没有定制模型,但有一个cusomtom TreeNode。以下是SSCCE:
package com.example.jtree;
//lots of obvious imports
public class JTreeBoundsExample extends JFrame {
public static void main(String... args) {
JTreeBoundsExample m = new JTreeBoundsExample();
m.setSize(275, 300);
m.setDefaultCloseOperation(EXIT_ON_CLOSE);
m.setVisible(true);
}
public JTreeBoundsExample() {
ValueTreeNode root = new ValueTreeNode(null, "root");
ValueTreeNode category = new ValueTreeNode(root, "category");
category.put("k1", new ValueTreeNode(category, "v1"));
category.put("k2", new ValueTreeNode(category, "v2"));
category.put("k3", new ValueTreeNode(category, "v3"));
root.put("category", category);
JTree tree = new JTree(root);
tree.setCellRenderer(new ValueCellRenderer());
tree.setRootVisible(false);
tree.expandRow(0);
for (int i = 0; i < tree.getRowCount(); i++) {
TreePath tp = tree.getPathForRow(i);
tree.makeVisible(tp);
System.out.println("Bounds of row " + i + ": " + tree.getPathBounds(tp));
}
Container content = getContentPane();
content.add(new JScrollPane(tree), BorderLayout.CENTER);
}
private static class ValueTreeNode extends HashMap<String, ValueTreeNode> implements TreeNode {
private List<String> keys = new ArrayList<String>();
private TreeNode parent;
private String value;
public ValueTreeNode(TreeNode parent, String value) {
this.parent = parent;
this.value = value;
}
@Override
public ValueTreeNode put(String key, ValueTreeNode val) {
ValueTreeNode old = super.put(key, val);
if (old == null) {
sortKeys();
}
return old;
}
private void sortKeys() {
keys.clear();
keys.addAll(keySet());
Collections.sort(keys);
}
@Override
public Enumeration children() {
final Iterator<String> it = keys.iterator();
return new Enumeration() {
@Override
public boolean hasMoreElements() {
return it.hasNext();
}
@Override
public Object nextElement() {
return it.next();
}
};
}
@Override
public boolean getAllowsChildren() {
return true;
}
@Override
public TreeNode getChildAt(int pos) {
return get(keys.get(pos));
}
@Override
public int getChildCount() {
return size();
}
@Override
public int getIndex(TreeNode arg0) {
return -1;
}
@Override
public TreeNode getParent() {
return parent;
}
@Override
public boolean isLeaf() {
return size() == 0;
}
}
private static class ValueCellRenderer extends DefaultTreeCellRenderer {
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded,
boolean leaf, int row, boolean hasFocus) {
super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
if (value instanceof ValueTreeNode) {
ValueTreeNode vtn = (ValueTreeNode) value;
setText(vtn.value);
}
return this;
}
}
}
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