java - 动态删除所有按钮

Question

我用过这个answer动态地将按钮添加到我的 GUI 中，并期望能够删除所有按钮。据我了解，我正在获取 HashMap (字符串)中的所有键，然后对键进行 for 循环，并从 HashMap 中删除它们(获取要删除的对象)。问题是，从 HashMap 中删除第一个按钮后，循环不再继续，我的应用程序崩溃了。

HashMap<String, JButton> buttonCache = new HashMap<>();
Set<String> names = buttonCache.keySet();
    /*
     * Checking which buttons exist in the hashmap
    */
    for (String name0 : names) {
        System.out.println("Name0: " + name0);
    }

    for (String name1 : names) {
        System.out.println("before removing: " + name1);
        buttonCache.containsKey(name1); //making sure its in it.
        JButton b = buttonCache.remove(name1);
        System.out.println("after removing: " + name1);
        //visualUI.remove(b); //not tested yet
    }
    //visualUI.invalidate();  //not tested yet
    //visualUI.repaint();     //not tested yet

输出为:

Name0: Cancel
Name0: Continue
2
before removing: Cancel
true
after removing: Cancel

Answer 1

如果你想从 HashMap 中删除，你需要借助迭代器来删除。
请参阅Calling remove in foreach loop in Java 。

编辑:根据OP...

Iterator<String> it = names.iterator(); 
while(it.hasNext()) { 
  System.out.println(names); 
  String buttonName = it.next(); 
  JButton b = buttonCache.get(buttonName); 
  it.remove(); 
} 
System.out.println(names);