swing Java带来的小程序GUI问题
我很难理解在我的掷骰子游戏中repaint()
在哪里和什么时候。我知道在每一个事件的实例之后,比如选择开始游戏或掷骰子时,我需要把repaint()
。但是,当我将字符串输出从“”更改为“You's wind!!”在每种情况下,再重新打印,应用程序都无法识别它。我已经扫描了这个网站,寻找可能的补救方法,但找不到任何像我正在使用的东西。gif是用于骰子图像的,我正在编写一个小程序,因此我不能只在主方法中使用sysout。任何批评都是欢迎的,我能应付
到目前为止我拥有的:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.*;
import java.util.Random;
public class Craps extends JApplet implements ActionListener {
Random gen = new Random();
// constant variables for game status
final int WON = 0, loss = 1, CONTINUE = 2;
// other variables used
boolean firstRoll = true; // true if first roll of dice
int diceSum = 1; // sum of the dice
int aPoint = 1; // point if no win/loss on first roll
int stillGame = CONTINUE; // game not over yet
int dice1 = gen.nextInt(6) + 1;
int dice2 = gen.nextInt(6) + 1;
int diceSec, dice2Sec;
int Horizon = gen.nextInt(260) + 25;
int secHorizon = gen.nextInt(260) + 25;
int Vertical = gen.nextInt(150) + 40;
int SecVerto = gen.nextInt(150) + 40;
Image[] dice = new Image[6];
int Low = 35, High = 335;
int Up = 50, Down = 250;
int wins = 0;
String s1 = "";
// GUI
JButton rollButton, startButton;
public void init() {
Button rollButton = new Button("Roll Dice");
Button startButton = new Button("Start Game");
setSize(400, 400);
setLayout(null);
for (int i = 0; i < 6; i++) {
dice[i] = getImage(getCodeBase(), "dice" + (i + 1) + ".gif");
}
// create button to start the game
startButton.setBounds(40, 300, 100, 20);
add(startButton);
startButton.addActionListener(this);
startButton.setEnabled(true);
// create button to roll dice
rollButton.setBounds(230, 300, 100, 20);
add(rollButton);
rollButton.addActionListener(this);
rollButton.setEnabled(true);
} // end of init
public void paint(Graphics g) {
super.paint(g);
// draw craps table
g.setColor(Color.red);
g.fillRect(1, 1, 400, 400);
// draw playing field
g.setColor(Color.green);
g.fillRoundRect(25, 40, 310, 210, 75, 75);
// paint the images of the dice
g.drawImage(dice[dice1 - 1], Horizon, Vertical, 32, 32, this);
g.drawImage(dice[dice2 - 1], secHorizon, SecVerto, 32, 32, this);
g.setColor(Color.black);
g.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 22));
g.drawString(s1, 33, 280);
}
public void actionPerformed(ActionEvent e) {
// first roll of dice
Horizon = gen.nextInt(260) + 25;
secHorizon = gen.nextInt(260) + 25;
Vertical = gen.nextInt(150) + 40;
SecVerto = gen.nextInt(150) + 40;
if (e.getSource() == rollButton) {
// while (stillGame == CONTINUE) {
if (firstRoll) {
diceSum = diceRoller(); // roll dice
// repaint();
switch (diceSum) {
// user victory on first roll
case 7:
case 11:
stillGame = WON;
s1 = "You Win";
wins++;
break;
// user loss on first roll
case 2:
case 3:
case 12:
stillGame = loss;
s1 = "You Lose";
break;
default:
stillGame = CONTINUE;
aPoint = diceSum;
firstRoll = false;
s1 = "The Point is " + aPoint + "";
break;
} // end switch
// end if (firstRoll) statement
repaint();
}
else {
diceSum = diceRoller(); // roll dice
// determine game status
if (diceSum == aPoint) // win by making point
s1 = "You Win!!";
else if (diceSum == 7) // lose by rolling seven
s1 = "Suck It";
}
// end while loop
} // end if structure body
// subsequent roll of dice
else {
diceSum = diceRoller(); // roll dice
// determine game status
if (diceSum == aPoint) { // win by making point
s1 = "You Win!!";
stillGame = WON;
} else if (diceSum == 7) { // lose by rolling seven
s1 = "You've Lost";
stillGame = loss;
}
}// end else structure
if (e.getSource() == startButton) {
s1 = "";
}
repaint();
}
// roll dice, calculate sum and display results
public int diceRoller() {
int sum;
dice1 = gen.nextInt(6) + 1; // pick random dice values
dice2 = gen.nextInt(6) + 1;
sum = dice1 + dice2; // sum die values
return sum; // return the sum of dice
} // end method rollDice
} // end
# 1 楼答案
似乎你在下一步中遇到了问题:在
init()
方法中,你声明了局部变量:并将
ActionListener
添加到它们中,但在actionPerformed(ActionEvent e)
方法中,可以将source与null进行比较:这里:
rollButton == null
和startButton == null
,正因为如此,你的if
语句永远不会执行,只执行else
语句在
init()
方法中声明按钮,如下一步:我觉得这对你有帮助
还可以阅读java中的variables