当我点击它时,我正试图将我的按钮从“开始”更改为“停止”。我尝试这样做是在下面,我查了一下并试图复制指南,但我看不出我做错了什么。我可能会遗漏一些“}”,因为我遗漏了许多不相关的代码。有人能看出我做错了吗?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class PipeGameApp extends JFrame implements ActionListener {
private static int BOARD_SIZE = 11;
private PipeGame game; // The model
private PipeGameView view; // The view
// This constructor builds the window
public PipeGameApp(String title) {
super(title);
game = new PipeGame(BOARD_SIZE);
view = new PipeGameView(game);
//THE TOP BAR
JPanel topBar = new JPanel();
JButton startButton = new JButton("Start");
startButton.addActionListener(this);
ButtonGroup bg1 = new ButtonGroup();
JRadioButton rb1 = new JRadioButton("2 minutes", true);
rb1.addActionListener(this);
JRadioButton rb2 = new JRadioButton("10 minutes", false);
JRadioButton rb3 = new JRadioButton("No Time Limit", false);
bg1.add(rb1);
bg1.add(rb2);
bg1.add(rb3);
topBar.add(startButton);
topBar.add(rb1);
topBar.add(rb2);
topBar.add(rb3);
//END OF TOP BAR
//THE BOTTOM BAR
JPanel bottomBar = new JPanel();
JLabel timeLeft = new JLabel("Time Left: ");
JProgressBar bar = new JProgressBar();
bottomBar.add(timeLeft);
bottomBar.add(bar);
bottomBar.setVisible(false);
//end of bottom
/*
//bottom 2
int fscore=10;
JPanel bottomBar2 = new JPanel();
JLabel score = new JLabel("Final score:" + fscore);
bottomBar2.add(score);
bottomBar2.setVisible(false);
*/
getContentPane().add(view); //CHANGE LOCATION OF BOARD GAME HERE BorderLayout.SOUTH
getContentPane().add(topBar, BorderLayout.NORTH);
getContentPane().add(bottomBar, BorderLayout.SOUTH);
//getContentPane().add(bottomBar2, BorderLayout.SOUTH);
// Add the listeners to the view's buttons
for (int r = 0; r < BOARD_SIZE; r++) {
for (int c = 0; c < BOARD_SIZE; c++) {
view.getButton(r, c).addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
handleTileSelection(e);
}
});
}
}
setDefaultCloseOperation(EXIT_ON_CLOSE);
//setSize(446,466);
setSize(446, 530);
setResizable(false);
}
// Handle a Tile Selection. Just change the model and update the view.
private void handleTileSelection(ActionEvent e) {
// Find the row and column of the pressed button, then make the change
int r = 0, c = 0;
for (int i = 0; i < BOARD_SIZE; i++) {
for (int j = 0; j < BOARD_SIZE; j++) {
if (e.getSource() == view.getButton(i, j)) {
if (game.placePipe(i, j)) {
view.update();
}
return;
}
}
}
}
// This is where it all begins
public static void main(String[] args) {
new PipeGameApp("The Frantic Pipe Layer").setVisible(true);
}
@Override
public void actionPerformed(ActionEvent ae) {
startButton.setText("asdf");
}
}
答案 0 :(得分:5)
您的问题是有限的变量范围之一。您的startButton变量在构造函数中声明,因此仅在构造函数中可见。你需要在类中声明它而不是在构造函数中重新声明它,允许类的其余部分能够“看到”变量并使用它。
即改变这个:
public class PipeGameApp extends JFrame implements ActionListener {
private static int BOARD_SIZE = 11;
private PipeGame game; // The model
private PipeGameView view; // The view
public PipeGameApp(String title) {
JButton startButton = new JButton("Start");
startButton.addActionListener(this);
// etc...
到此:
public class PipeGameApp extends JFrame implements ActionListener {
private static int BOARD_SIZE = 11;
private PipeGame game; // The model
private PipeGameView view; // The view
private JButton startButton; // *** note change ***
public PipeGameApp(String title) {
startButton = new JButton("Start"); // *** note change ***
startButton.addActionListener(this);
// etc...
可替换地:
getSource()
方法返回的对象,并根据其当前状态设置它的新状态。例如,
@Override
public void actionPerformed(ActionEvent ae) {
Object source = ae.getSource();
if (source instanceof JButton) {
if (ae.getText().equals("Start")) {
ae.setText("Stop");
// do other stuff
} else if (ae.getText().equals("Stop")) {
ae.setText("Start");
// do more stuff
}
}
}
关于"I might be missing some "}" because I left out a lot of the code that's irrelevant."
请付出努力,以免发生这种情况。缺少“}”不应该丢失,这使我们更难理解您的代码并帮助您。如果你要求其他人努力帮助你腾出空闲时间,那就不要求你过多地发布垃圾代码。
答案 1 :(得分:2)
您在main
方法之后保留了构造函数的结束括号。这是更正后的代码。
public PipeGameApp(String title) {
super(title);
JPanel topBar = new JPanel();
JButton startButton = new JButton("Start");
startButton.addActionListener(this);
}
public static void main(String[] args) {
new PipeGameApp("The Frantic Pipe Layer").setVisible(true);
}
@Override
public void actionPerformed(ActionEvent ae) {
startButton.setText("asdf");
}