我试图编写一个小迷宫跑步者程序，并且遇到了与paintComponent（）相关的一些麻烦。我已经完成了调试，由于某种原因，我的paintComponent（）从未被调用，即使我的计时器调用了repaint（）。
private void jpanelinit() {
JPanel Background = new JPanel (new BorderLayout());
JPanel Menu = new JPanel (new BorderLayout());
JPanel Maze = new JPanel (new GridLayout(arow, acolumn));
Background.setPreferredSize(new Dimension(850,850));
Menu.setPreferredSize(new Dimension(850, 100));
Maze.setPreferredSize(new Dimension(850,750));
frame.add(Background);
comboboxinit();
Background.add(Menu, BorderLayout.NORTH);
Background.add(Maze, BorderLayout.SOUTH);
Menu.add(Startpause, BorderLayout.WEST);
Menu.add(Reset, BorderLayout.EAST);
Menu.add(Intervalpick, BorderLayout.CENTER);
Intervalpick.setVisible(true);
Intervalpick.addActionListener(this);
Startpause.setVisible(true);
Startpause.addActionListener(this);
Reset.setVisible(true);
Reset.addActionListener(this);
Maze.setVisible(true);
}
private static void frameinit() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setSize(850,850);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
这些是我的frame和jpanel init方法。
@Override
public void paintComponent(Graphics g){
System.out.println("Entered Graphics");
super.paintComponent(g);
g.drawImage(biWall,0,100,850,750, this );
}
这是我的paintComponent，图像确实已缓冲并已存储。
public void actionPerformed(ActionEvent e) {
if(e.getSource()==Intervalpick)
timecheck(); //Checks if the time was changed
if(e.getSource()==Startpause||e.getSource()==Reset)
buttoncheck(e); //Checks if the buttons were pressed
if(t.isRunning())
mazeupdate();
}
private void mazeupdate() {
repaint();
}
这是我的actionPerformed，用我的计时器调用，默认设置为5秒。
public class mazerunner extends JPanel implements ActionListener {
static JButton Startpause = new JButton("Start");
static JButton Reset = new JButton("Reset");
static JComboBox Intervalpick= new JComboBox();
static JFrame frame=new JFrame ("Maze Runner");
static int arow=0, acolumn=0, icurrenttime=5000;
static boolean gameplaying=false;
static Timer t;
static BufferedImage biWall, biFloor, biMouse, biCheese;
public static void main(String[] args) {
mazerunner mr= new mazerunner();
filereader(); //Reads the file
imagebuffer(); //Buffers the images
mr.jpanelinit(); //Inits the gui
frameinit(); //Inits the frame
mr.timerinit(); //Inits the timer
}
private static void imagebuffer() {
try{
biWall=ImageIO.read(new File("cobblewall.jpg"));
}
catch(IOException e){}
try{
biFloor=ImageIO.read(new File("woodenfloor.jpg"));
}
catch(IOException e){}
try{
biCheese=ImageIO.read(new File("chest_cheese.jpg"));
}
catch(IOException e){}
try{
biMouse=ImageIO.read(new File("lara_mouse.jpg"));
}
catch(IOException e){}
}
private void timerinit() {
t=new Timer(icurrenttime,this);
}
private void jpanelinit() {
JPanel Background = new JPanel (new BorderLayout()); //Inits all the JPanels
JPanel Menu = new JPanel (new BorderLayout());
JPanel Maze = new JPanel (new GridLayout(arow, acolumn));
Background.setPreferredSize(new Dimension(850,850)); //Sets the size of the panels
Menu.setPreferredSize(new Dimension(850, 100));
Maze.setPreferredSize(new Dimension(850,750));
frame.add(Background); //Adds background into the frame
comboboxinit();
Background.add(Menu, BorderLayout.NORTH); //Adds the other panels into the background
Background.add(Maze, BorderLayout.SOUTH);
Menu.add(Startpause, BorderLayout.WEST); //Adds the menu's components into the menu panel
Menu.add(Reset, BorderLayout.EAST);
Menu.add(Intervalpick, BorderLayout.CENTER);
Intervalpick.setVisible(true); //Sets the components to visible and adds actionlistener
Intervalpick.addActionListener(this);
Startpause.setVisible(true);
Startpause.addActionListener(this);
Reset.setVisible(true);
Reset.addActionListener(this);
Maze.setVisible(true);
}
private static void comboboxinit() {
for(int a=5;a<=30;a=a+5){ //Sets the text inside the combobox
Intervalpick.addItem(a+" Seconds");
}
DefaultListCellRenderer dlcr = new DefaultListCellRenderer(); //Centers the text inside the combobox
dlcr.setHorizontalAlignment(DefaultListCellRenderer.CENTER);
Intervalpick.setRenderer(dlcr);
}
private static void frameinit() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Inits the jframe
frame.setResizable(false);
frame.setSize(850,850);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
private static void filereader() {
try{
FileReader fr=new FileReader("maze.txt");
BufferedReader br= new BufferedReader(fr);
String LineIn=br.readLine();
int num, row=0;
arow=Integer.parseInt(LineIn);
LineIn=br.readLine();
acolumn=Integer.parseInt(LineIn);
int Maze[][]=new int[arow][acolumn]; //inits the maze itself
LineIn=br.readLine();
do{ //stores the maze from the file into the arrray
int collumn=0;
StringTokenizer tokens=new StringTokenizer(LineIn);
while (tokens.hasMoreTokens()){
num=Integer.parseInt(tokens.nextToken());
Maze[row][collumn]=num;
collumn++;
}
LineIn=br.readLine();
row++;
}while(LineIn!=null);
br.close();
fr.close();
}
catch(FileNotFoundException e){
System.err.println("file not found");
}
catch(IOException e){
System.err.println("read failed");
}
}
@Override
public void paintComponent(Graphics g){
System.out.println("Entered Graphics");
super.paintComponent(g);
g.drawImage(biWall,0,100,850,750, this );
}
public void actionPerformed(ActionEvent e) {
if(e.getSource()==Intervalpick)
timecheck(); //Checks if the time was changed
if(e.getSource()==Startpause||e.getSource()==Reset)
buttoncheck(e); //Checks if the buttons were pressed
if(t.isRunning())
mazeupdate();
}
private void mazeupdate() {
repaint();
}
private void buttoncheck(ActionEvent e) {
if(e.getSource()==Startpause){ //Starts and pauses the simulation
if(gameplaying==false){
gameplaying=true;
t.start();
Startpause.setText("Pause");
}
else if(gameplaying==true){
gameplaying=false;
t.stop();
Startpause.setText("Start");
}
}
else if(e.getSource()==Reset){ //Resets the maze to the original maze
if(t.isRunning())
t.stop();
gameplaying=false;
Startpause.setText("Start");
filereader();
// t.repaint();
}
}
private void timecheck() {
int boxtime= Integer.parseInt(((String) Intervalpick.getSelectedItem()).split(" ")[0])*1000; //Turns Intervalpick into a milisecond amount
if(boxtime!=icurrenttime){ //Checks if the selected delay is equal to the actual delay
boolean gamerunning=false;
icurrenttime=boxtime;
if(t.isRunning()){ //Stops timer if running
t.stop();
gamerunning=true;
}
t.setDelay(icurrenttime); //Changes delay
if(gamerunning==true) //If timer was running it turns it back on
t.start();
}
}
}
如果您有兴趣，这是我的完整代码。我的问题是为什么我无法将图像绘制到迷宫面板上。
答案 0 :(得分：1)
paintComponent无法被召唤。
0x0 浏览您的代码，我无法找到mazerunner实际添加frame的实例...
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