java - 我有一个 HashMap 如何将它与 GUI 集成；我想输入整数并获取字符串值。

Question

我有五十个州的 HashMap；我想使用一个 GUI，您可以从 HashMap 输入整数，结果是字符串。我知道“JOptionPane”是什么，但我不知道如何将它与 GUI 集成。

import java.util.HashMap;

public class FIftyStates {

public static void main(String[] args) {

    HashMap<Integer, String> FiftyStates = new HashMap <Integer, String>();




    FiftyStates.put(1,"Delaware");
    FiftyStates.put(2,"Pennsylvania");
    FiftyStates.put(3,"New Jersey"); 
    FiftyStates.put(4,"Georgia");
    FiftyStates.put(5,"Connecticut");
    FiftyStates.put(6,"Massachusetts" );
    FiftyStates.put(7,"Maryland");
    FiftyStates.put(8,"South Carolina");
    FiftyStates.put(9,"New Hampshire");
    FiftyStates.put(10,"Virginia");
    FiftyStates.put(11,"New York");
    FiftyStates.put(12,"North Carolina");
    FiftyStates.put(13,"Rhode Island");
    FiftyStates.put(14,"Vermont");
    FiftyStates.put(15,"Kentucky");
    FiftyStates.put(16,"Tennessee");
    FiftyStates.put(17,"Ohio");
    FiftyStates.put(18,"Louisiana");
    FiftyStates.put(19,"Indiana");
    FiftyStates.put(20,"Mississippi");
    FiftyStates.put(21,"Illinois");
    FiftyStates.put(22,"Alabama");
    FiftyStates.put(23,"Maine");
    FiftyStates.put(24,"Missouri");
    FiftyStates.put(25,"Arkansas");
    FiftyStates.put(26,"Michagan");
    FiftyStates.put(27,"Florida");
    FiftyStates.put(28,"Texas");
    FiftyStates.put(29,"Iowa");
    FiftyStates.put(30,"Wisconsin");
    FiftyStates.put(31,"California");
    FiftyStates.put(32,"Minnesota");
    FiftyStates.put(33,"Oregon");
    FiftyStates.put(34,"Kansas");
    FiftyStates.put(35,"West Virginia");
    FiftyStates.put(36,"Nevada");
    FiftyStates.put(37,"Nebraska");
    FiftyStates.put(38,"Colorado");
    FiftyStates.put(39,"North Dakota");
    FiftyStates.put(40,"South Dakota");
    FiftyStates.put(41,"Montana");
    FiftyStates.put(42,"Washington");
    FiftyStates.put(43,"Idaho");
    FiftyStates.put(44,"Wyoming");
    FiftyStates.put(45,"Utah");
    FiftyStates.put(46,"Oklahoma");
    FiftyStates.put(47,"New Mexico");
    FiftyStates.put(48,"Arizona");
    FiftyStates.put(49,"Alaska");
    FiftyStates.put(50,"Hawaii");
}

}

Answer 1

你可以...

做一些类似的事情

int selected = -1;
do {
    String value = JOptionPane.showInputDialog(null, "Pick a state: ", "Pick a state", JOptionPane.QUESTION_MESSAGE);
    try {
        selected = Integer.parseInt(value);
    } catch (NumberFormatException exp) {
        selected = -1;
    }
} while (selected == -1);

JOptionPane.showMessageDialog(null, "You selected " + FiftyStates.get(selected));

但坦率地说，这是一种非常糟糕的用户体验，相反......

你可以...

做一些更像......的事情

Object value = JOptionPane.showInputDialog(null, "Help", "Help", JOptionPane.QUESTION_MESSAGE, null, FiftyStates.values().toArray(new String[FiftyStates.size()]), null);
JOptionPane.showMessageDialog(null, "You selected " + value);

这将提供更好的用户体验

How can I have it print the "integer" as well?

Set<Map.Entry<Integer, String>> entrySet = FiftyStates.entrySet();
DefaultComboBoxModel model = new DefaultComboBoxModel();
for (Map.Entry<Integer, String> entry : entrySet) {
    model.addElement(entry);
}
JComboBox cb = new JComboBox(model);
cb.setRenderer(new DefaultListCellRenderer() {
    @Override
    public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
        if (value instanceof Map.Entry) {
            value = ((Map.Entry)value).getValue();
        }
        return super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
    }
});

JOptionPane.showMessageDialog(null, cb, "Select State", JOptionPane.QUESTION_MESSAGE);
Object selectedItem = cb.getSelectedItem();
if (selectedItem != null && selectedItem instanceof Map.Entry) {
    Map.Entry<Integer, String> entry = (Map.Entry<Integer, String>) selectedItem;
    JOptionPane.showMessageDialog(null, "You selected " + entry.getKey() + "/" + entry.getValue());
}