我使用Java AWT创建了以下shuffle难题。在程序开始时，如您所见，所有数字都是有序的。我想生成随机数而不重复。这该怎么做？我应该使用Random课吗？
import java.awt.*;
import java.awt.event.*;
class Puzzle extends Frame implements ActionListener
{
Button b1,b2,b3,b4,b5,b6,b7,b8,b9;
Puzzle()
{
setTitle("Shuffle");
setSize(500,500);
setLayout(new GridLayout(3,3));
setVisible(true);
Font f=new Font("Arial",Font.BOLD,100);
b1=new Button("1");
b1.setFont(f);
b1.addActionListener(this);
b2=new Button("2");
b2.setFont(f);
b2.addActionListener(this);
b3=new Button("3");
b3.setFont(f);
b3.addActionListener(this);
b4=new Button("4");
b4.setFont(f);
b4.addActionListener(this);
b5=new Button("5");
b5.setFont(f);
b5.addActionListener(this);
b6=new Button("6");
b6.setFont(f);
b6.addActionListener(this);
b7=new Button("7");
b7.setFont(f);
b7.addActionListener(this);
b8=new Button("8");
b8.setFont(f);
b8.addActionListener(this);
b9=new Button(" ");
b9.setFont(f);
b9.addActionListener(this);
add(b1); add(b2); add(b3);
add(b4); add(b5); add(b6);
add(b7); add(b8); add(b9);
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getSource() == b1)
{
if(b2.getLabel() == " ")
{
b2.setLabel(b1.getLabel());
b1.setLabel(" ");
}
else if(b4.getLabel() == " ")
{
b4.setLabel(b1.getLabel());
b1.setLabel(" ");
}
}
if(ae.getSource() == b2)
{
if(b1.getLabel() == " ")
{
b1.setLabel(b2.getLabel());
b2.setLabel(" ");
}
else if(b3.getLabel() == " ")
{
b3.setLabel(b2.getLabel());
b2.setLabel(" ");
}
else if(b5.getLabel() == " ")
{
b5.setLabel(b2.getLabel());
b2.setLabel(" ");
}
}
if(ae.getSource() == b3)
{
if(b2.getLabel() == " ")
{
b2.setLabel(b3.getLabel());
b3.setLabel(" ");
}
else if(b6.getLabel() == " ")
{
b6.setLabel(b3.getLabel());
b3.setLabel(" ");
}
}
if(ae.getSource() == b4)
{
if(b1.getLabel() == " ")
{
b1.setLabel(b4.getLabel());
b4.setLabel(" ");
}
else if(b5.getLabel() == " ")
{
b5.setLabel(b4.getLabel());
b4.setLabel(" ");
}
else if(b7.getLabel() == " ")
{
b7.setLabel(b4.getLabel());
b4.setLabel(" ");
}
}
if(ae.getSource() == b5)
{
if(b2.getLabel() == " ")
{
b2.setLabel(b5.getLabel());
b5.setLabel(" ");
}
else if(b4.getLabel() == " ")
{
b4.setLabel(b5.getLabel());
b5.setLabel(" ");
}
else if(b6.getLabel() == " ")
{
b6.setLabel(b5.getLabel());
b5.setLabel(" ");
}
else if(b8.getLabel() == " ")
{
b8.setLabel(b5.getLabel());
b5.setLabel(" ");
}
}
if(ae.getSource() == b6)
{
if(b3.getLabel() == " ")
{
b3.setLabel(b6.getLabel());
b6.setLabel(" ");
}
else if(b5.getLabel() == " ")
{
b5.setLabel(b6.getLabel());
b6.setLabel(" ");
}
else if(b9.getLabel() == " ")
{
b9.setLabel(b6.getLabel());
b6.setLabel(" ");
}
}
if(ae.getSource() == b7)
{
if(b4.getLabel() == " ")
{
b4.setLabel(b7.getLabel());
b7.setLabel(" ");
}
else if(b8.getLabel() == " ")
{
b8.setLabel(b7.getLabel());
b7.setLabel(" ");
}
}
if(ae.getSource() == b8)
{
if(b5.getLabel() == " ")
{
b5.setLabel(b8.getLabel());
b8.setLabel(" ");
}
else if(b7.getLabel() == " ")
{
b7.setLabel(b8.getLabel());
b8.setLabel(" ");
}
else if(b9.getLabel() == " ")
{
b9.setLabel(b8.getLabel());
b8.setLabel(" ");
}
}
if(ae.getSource() == b9)
{
if(b6.getLabel() == " ")
{
b6.setLabel(b9.getLabel());
b9.setLabel(" ");
}
else if(b8.getLabel() == " ")
{
b8.setLabel(b9.getLabel());
b9.setLabel(" ");
}
}
}
public static void main(String args[])
{
new Puzzle();
}
}
答案 0 :(得分：1)
您可以这样做：
// global scope
List<Integer> container = new ArrayList<>();
//populate it
for(int i =1; i<=8; i++){
container.add(i);
}
..........
..........
..........
public static int getRandom(){
//to refill it if ya need to call it more than 8 times
//if(container.size()==0){for(int i=1; i<=8; i++){container.add(i);}
Random generator = new Random();
Integer randomNumber = container.get(generator.nextInt(container.size()));
container.remove(randomNumber);
return randomNumber;
}
此外，如果您想要随机命名/标记每个按钮，其中包含1到8个唯一编号，只需例如：
b1=new Button(String.valueOf(getRandom()));
等等。
答案 1 :(得分：0)
一般答案：
编辑：我道歉，其他人发布的内容与此基本相同。他先做到了。ArrayList<Integer> draw = new ArrayList<Integer>();
for(int i = 1; i<=8; i++){
draw.add(i); //Add every number once
}
//Every time you call it, you pick a random item from the list.
//Then you remove it from it to prevent being recalled. Therefore it won't be re-accesed.
Random r = new Random();
int placeholder = r.nextInt(draw.size());
int num = draw.get(placeholder);
draw.remove(placeholder);
对你来说，这就是你应该做的：
...
ArrayList<Button> buttonlist = new ArrayList<Button>(); /// ADD THIS. Put this outside the method/function.
...
Puzzle(){
setTitle("Shuffle");
setSize(500,500);
setLayout(new GridLayout(3,3));
setVisible(true);
Font f=new Font("Arial",Font.BOLD,100);
b1=new Button("1");
b1.setFont(f);
b1.addActionListener(this);
buttonlist.add(b1); /// ADD THIS
b2=new Button("2");
b2.setFont(f);
b2.addActionListener(this);
buttonlist.add(b2); /// ADD THIS
b3=new Button("3");
b3.setFont(f);
b3.addActionListener(this);
buttonlist.add(b3); /// ADD THIS
b4=new Button("4");
b4.setFont(f);
b4.addActionListener(this);
buttonlist.add(b4); /// ADD THIS
b5=new Button("5");
b5.setFont(f);
b5.addActionListener(this);
buttonlist.add(b5); /// ADD THIS
b6=new Button("6");
b6.setFont(f);
b6.addActionListener(this);
buttonlist.add(b6); /// ADD THIS
b7=new Button("7");
b7.setFont(f);
b7.addActionListener(this);
buttonlist.add(b7); /// ADD THIS
b8=new Button("8");
b8.setFont(f);
b8.addActionListener(this);
buttonlist.add(b8); /// ADD THIS
b9=new Button(" ");
b9.setFont(f);
b9.addActionListener(this);
buttonlist.add(b9); /// ADD THIS
Random r = new Random(); /// ADD THIS
while(buttonlist.size() != 0){ /// ADD THIS
int placeholder = r.nextInt(buttonlist.size()); /// ADD THIS
Button button = buttonlist.get(placeholder); /// ADD THIS
add(button); /// ADD THIS AFTER REPLACING all the original add(b1)...
buttonlist.remove(placeholder); /// ADD THIS
} /// ADD THIS
}
这与其他建议给出个人名称的回复略有不同，我相信这种方法会更好一点，所以b1没有标签3或其他东西。这样，对顺序进行洗牌的答案就是b1，b2，b3 ......而不是随机顺序。这实际上是在边框上按下按钮时保留顺序，否则您将难以识别对象。
答案 2 :(得分：0)
由于您是从一个集合中随机选择一个数字，请不要使用Random数字生成器来选择该数字，使用Random数字生成器从剩余的可用数字中选择。
List<Integer> choices = getNewChoices();
int choice = choices.remove(random.nextInt(choices.size());
选择最终会变得越来越小，但未选中的元素仍然在List。
您可以将其包含在保护方法selectOne
public class Whatever {
public void run() {
...
List<Integer> choices = getNewChoices();
...
int choice = selectOne(choices);
}
public List<Integer> getNewChoices() {
return Arrays.toList(new Integer[] { 1, 2, 3, 4, 5, 6, 7, 8});
}
public int selectOne(List<Integer> choices) {
if (choices.length() > 0) {
return choices.remove(random.nextInt(choices.size());
}
throw new RuntimeException("out of choices");
}
}