在外部类中,我多次调用这些方法,但是setBackground()仅在我首次调用这些方法中的任何时候才起作用。
例如,我有对象CellPane cellpane1, cellpane2
,当我第一次调用cellpane1.drawPlayer()
时,它按预期工作,当我第一次调用cellpane2.drawWall()
时,它也按预期工作。但是,当我在调用cellpane1.drawWall()
后为cellpane1,cellpane1.drawPlayer()
调用drawWall()时,它不起作用。背景颜色没有改变。
我需要重新粉刷或重新失效,还是什么?我是这些东西的新手。 :(我做错了什么?
private static class CellPane extends JPanel {
private Color defaultBackground;
private CellPane() {
addMouseListener(new MouseAdapter() {
@Override
public void mouseEntered(MouseEvent e) {
defaultBackground = getBackground();
setBackground(Color.BLUE);
}
@Override
public void mouseExited(MouseEvent e) {
setBackground(defaultBackground);
}
});
}
private void drawDefault() {
setBackground(defaultBackground);
}
private void drawBoxOnGoal() {
defaultBackground = getBackground();
setBackground(Color.decode("#4a3d32"));
}
private void drawPlayerOnGoal() {
defaultBackground = getBackground();
setBackground(Color.decode("#f9cda8"));
}
private void drawGoal() {
defaultBackground = getBackground();
setBackground(Color.decode("#f9cda8"));
}
private void drawBox() {
defaultBackground = getBackground();
setBackground(Color.decode("#7a5230"));
}
private void drawPlayer() {
defaultBackground = getBackground();
setBackground(Color.YELLOW);
}
private void drawWall() {
defaultBackground = getBackground();
setBackground(Color.RED);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(50, 50);
}
}
[编辑]
例:
public class MainClass {
public static void main(String[] args) {
new MainClass();
}
private MainClass() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { }
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new Map());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private static class Map extends JPanel implements ActionListener{
CellPane cellPane;
boolean flag = true;
JButton button = new JButton("button");
public Map() {
setLayout(new GridBagLayout());
button.addActionListener(this);
add(button);
create(flag);
}
public void create(boolean flag) {
GridBagConstraints gbc = new GridBagConstraints();
cellPane = new CellPane();
gbc.gridx = 0;
gbc.gridy = 0;
if(flag)
cellPane.drawPlayer();
else cellPane.drawWall();
add(cellPane, gbc);
}
@Override
public void actionPerformed(ActionEvent arg0) {
flag = false;
create(flag);
}
}
@SuppressWarnings("serial")
private static class CellPane extends JPanel {
private Color defaultBackground;
private void drawPlayer() {
defaultBackground = getBackground();
setBackground(Color.YELLOW);
}
private void drawWall() {
defaultBackground = getBackground();
setBackground(Color.RED);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(50, 50);
}
}}
我知道这不是一个完美的例子,但可以运行。所以我想在单击按钮时更改cellPane的背景。当flag为true且背景设置为YELLOW时,构造函数将调用create(flag)。然后单击按钮,标志变为false并调用create(flag),其中flag = false,因此它将调用cellPane.setWall()来设置背景红色,但不会。
我做错了什么?也许有些简单,但是我对这些东西还是陌生的。
最佳答案
单击按钮时,您不会更改cellPane的颜色。您正在创建另一种颜色不同的cellPane,并将其添加到与现有单元相同的gridbag单元中。
只需更改颜色,它将正常工作:
public Map() {
setLayout(new GridBagLayout());
button.addActionListener(this);
add(button);
create();
draw();
}
private void draw() {
if (flag) {
cellPane.drawPlayer();
}
else {
cellPane.drawWall();
}
}
private void create() {
GridBagConstraints gbc = new GridBagConstraints();
cellPane = new CellPane();
gbc.gridx = 0;
gbc.gridy = 0;
add(cellPane, gbc);
}
@Override
public void actionPerformed(ActionEvent arg0) {
flag = false;
draw();
}