我是Java的新手，甚至是NetBeans的新手......我只是想不通如何解决这个问题..
当我运行我的项目时，GUI最初没有显示出来。应该有一个菜单栏，其中包含用于打开和保存文件的下拉列表，以及退出程序。窗口底部还应该有三个按钮，可用于显示文件中的数据（本例中为图像）。但是，当你运行程序时，窗口是空白的，根本没有任何显示。
当我点击左上角时，“文件”位于菜单栏上..然后它会显示，此时顶部按钮也会显示。后两个按钮应该是灰色的，只有在您单击第一个按钮并显示第一个图像后才能点击。
我尝试过搜索解决方案，摆弄NetBeans设置，但似乎无法解决这个问题。我假设它与前景或背景中的错误放置有关，但我不确定。
另外，我发现如果我删除了drawImage位代码（（public void paint（Graphics g）{g.drawImage（imageToPaint，50,70，this）;}），那么GUI会出现，所以我猜猜这与某些东西有冲突......某处？！
如果有人能对此有所了解，请提前致谢！
package final_project;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.MemoryImageSource;
import java.util.*;
import javax.swing.*;
import javax.swing.filechooser.FileFilter;
import javax.swing.filechooser.FileNameExtensionFilter;
public abstract class Analyst extends javax.swing.JFrame
implements ActionListener {
double heights[][] = new double [300][300];
double grads[][] = new double [300][300];
double tempg[] = new double [8];
double wgrads[][] = new double [300][300];
Image imageToPaint;
public boolean shouldcolourheights = false;
int blue = 1;
int green = 1;
int red = 1;
public Analyst() {
initComponents();
}
public double [][] convertFromString(String[] stArray){
double[][] data = new double [300][300];
int lines = stArray.length;
for (int i = 0; i<lines; i++){
StringTokenizer st = new StringTokenizer(stArray[i]," ");
int j=0;
while (st.hasMoreTokens()){
data[i][j]=Double.parseDouble(st.nextToken());
j++;
}
}
return data;
}
double[] get1DArray (double[][] twoDarray) {
double[] tempArray = new double[twoDarray.length * twoDarray[0].length];
for (int i = 0; i < twoDarray.length; i++) {
for (int j = 0; j < twoDarray[i].length; j++) {
tempArray[(i * twoDarray[0].length) + j] = twoDarray[i][j];
}
}
return tempArray;
}
public double getMaxGrad (int bound){
double maxgrad = 0.0;
for (int k=0; k<bound; k++){
if (tempg[k]>maxgrad){
maxgrad=tempg[k];
}
}
return maxgrad;
}
public Image getImage (double [][] array) {
int arrayW = array[0].length;
int [] pixels = new int [array.length * arrayW];
double [] oneDim = get1DArray(array);
for (int i = 0; i < pixels.length; i++) {
int value = (int) oneDim[i];
if (value > 255){
value = 255;
}
if (shouldcolourheights){
int newi = (int) Math.floor(i/300);
int newj = (int) i-(newi*300);
if (grads[newi][newj] < 1.0){
blue=1; green=1; red=1;
} else if (grads[newi][newj] <=1.5) {
blue=0; red=0; green=1;
} else if (grads[newi][newj] <=3.0) {
blue=1; red=0; green=0;
} else {blue=0; red=1; green=0;}
}
Color pixel;
pixel = new Color(value * red, value * green, value * blue, 255);
pixels[i] = pixel.getRGB();
}
MemoryImageSource memImage = new MemoryImageSource(arrayW,arrayW,pixels,0,arrayW);
Panel p = new Panel();
Image image = p.createImage(memImage);
return image;
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
fc = new javax.swing.JFileChooser();
btnHeights = new javax.swing.JButton();
btnGradients = new javax.swing.JButton();
btnColourH = new javax.swing.JButton();
jMenuBar = new javax.swing.JMenuBar();
jMenu = new javax.swing.JMenu();
jMenuOpen = new javax.swing.JMenuItem();
jMenuSave = new javax.swing.JMenuItem();
jSeparator = new javax.swing.JPopupMenu.Separator();
jMenuExit = new javax.swing.JMenuItem();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
btnHeights.setText("Heights");
btnHeights.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnHeightsActionPerformed(evt);
}
});
btnGradients.setText("Gradients");
btnGradients.setEnabled(false);
btnGradients.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnGradientsActionPerformed(evt);
}
});
btnColourH.setText("Colour Heights");
btnColourH.setEnabled(false);
btnColourH.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnColourHActionPerformed(evt);
}
});
jMenu.setText("File");
jMenuOpen.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_O, java.awt.event.InputEvent.CTRL_MASK));
jMenuOpen.setText("Open");
jMenuOpen.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jMenuOpenActionPerformed(evt);
}
});
jMenu.add(jMenuOpen);
jMenuSave.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_S, java.awt.event.InputEvent.CTRL_MASK));
jMenuSave.setText("Save");
jMenuSave.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jMenuSaveActionPerformed(evt);
}
});
jMenu.add(jMenuSave);
jMenu.add(jSeparator);
jMenuExit.setText("Exit");
jMenuExit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jMenuExitActionPerformed(evt);
}
});
jMenu.add(jMenuExit);
jMenuBar.add(jMenu);
setJMenuBar(jMenuBar);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(39, 39, 39)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(btnColourH, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(btnGradients, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(btnHeights, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addContainerGap(258, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(381, Short.MAX_VALUE)
.addComponent(btnHeights)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnGradients)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnColourH)
.addGap(27, 27, 27))
);
pack();
}// </editor-fold>
private void jMenuOpenActionPerformed(java.awt.event.ActionEvent evt) {
FileFilter ft = new FileNameExtensionFilter("Text Files", "txt");
fc.addChoosableFileFilter(ft);
int returnVal = fc.showOpenDialog(this);
if (returnVal==javax.swing.JFileChooser.APPROVE_OPTION) {
java.io.File file = fc.getSelectedFile();
String file_name = file.toString();
try {
ReadFile file_read = new ReadFile(file_name);
String [] arraylines = file_read.OpenFile();
heights = convertFromString(arraylines);
}
catch (java.io.IOException e) {
JOptionPane.showMessageDialog(Analyst.this, "File does not exist");
}
}
}
private void jMenuSaveActionPerformed(java.awt.event.ActionEvent evt) {
String tempStr = "";
FileFilter ft = new FileNameExtensionFilter("Text Files", "txt");
fc.addChoosableFileFilter(ft);
int returnVal = fc.showSaveDialog(this);
if (returnVal==javax.swing.JFileChooser.APPROVE_OPTION) {
java.io.File saved_file = fc.getSelectedFile();
String file_name = saved_file.toString();
try {
WriteFile dataOut = new WriteFile(file_name, true);
for (int i=0; i<grads.length; i++) {
for (int j=0; j<grads[i].length; j++){
double rgrad = Math.floor(grads[i][j] * 10) / 10;
tempStr = tempStr + String.valueOf(rgrad) +" ";
}
dataOut.writeToFile(tempStr);
tempStr = "";
}
}
catch (java.io.IOException e) {
JOptionPane.showMessageDialog(Analyst.this, "File not written");
}
}
repaint();
}
private void jMenuExitActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
}
private void btnHeightsActionPerformed(java.awt.event.ActionEvent evt) {
shouldcolourheights=false;
red=1; blue=1; green=1;
imageToPaint = getImage(heights);
repaint();
btnGradients.setEnabled(true);
}
private void btnGradientsActionPerformed(java.awt.event.ActionEvent evt) {
double root2 = Math.sqrt(2.0);
double scaling = 1.0; //cells of 1m assumed
double weighting = 40.0; //to give more defined image
//The 8 neighbour cells
for (int i=1; i<299; i++) {
for (int j=1; j<299; j++){
tempg[0] = Math.abs(heights[i-1][j-1]-heights[i][j])/root2;
tempg[1] = Math.abs(heights[i-1][j+1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i+1][j-1]-heights[i][j])/root2;
tempg[3] = Math.abs(heights[i+1][j+1]-heights[i][j])/root2;
tempg[4] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[5] = Math.abs(heights[i-1][j]-heights[i][j]);
tempg[6] = Math.abs(heights[i][j+1]-heights[i][j]);
tempg[7] = Math.abs(heights[i+1][j]-heights[i][j]);
grads[i][j] = getMaxGrad(8)/scaling;
}
}
//The 5 neighbour cells
int i=0;
for (int j=1; j<299; j++) {
tempg[0] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[1] = Math.abs(heights[i+1][j-1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i+1][j]-heights[i][j]);
tempg[3] = Math.abs(heights[i+1][j+1]-heights[i][j])/root2;
tempg[4] = Math.abs(heights[i][j+1]-heights[i][j]);
grads[i][j] = getMaxGrad(5)/scaling;
}
i=299;
for (int j=1; j<299; j++){
tempg[0] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[1] = Math.abs(heights[i-1][j-1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i-1][j]-heights[i][j]);
tempg[3] = Math.abs(heights[i-1][j+1]-heights[i][j])/root2;
tempg[4] = Math.abs(heights[i][j+1]-heights[i][j]);
grads[i][j] = getMaxGrad(5)/scaling;
}
int j=0;
for (i=1; i<299; i++){
tempg[0] = Math.abs(heights[i-1][j]-heights[i][j]);
tempg[1] = Math.abs(heights[i-1][j+1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i][j+1]-heights[i][j]);
tempg[3] = Math.abs(heights[i+1][j+1]-heights[i][j])/root2;
tempg[4] = Math.abs(heights[i+1][j]-heights[i][j]);
grads[i][j] = getMaxGrad(5)/scaling;
}
j=299;
for (i=1; i<299; i++){
tempg[0] = Math.abs(heights[i+1][j]-heights[i][j]);
tempg[1] = Math.abs(heights[i+1][j-1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[3] = Math.abs(heights[i-1][j-1]-heights[i][j])/root2;
tempg[4] = Math.abs(heights[i-1][j]-heights[i][j]);
grads[i][j] = getMaxGrad(5)/scaling;
}
//The 3 neighbour cells
i=0; j=0;
tempg[0] = Math.abs(heights[i+1][j]-heights[i][j]);
tempg[1] = Math.abs(heights[i+1][j+1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i][j+1]-heights[i][j]);
grads[i][j] = getMaxGrad(3)/scaling;
i=299; j=0;
tempg[0] = Math.abs(heights[i-1][j]-heights[i][j]);
tempg[1] = Math.abs(heights[i-1][j+1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i][j+1]-heights[i][j]);
grads[i][j] = getMaxGrad(3)/scaling;
i=0; j=299;
tempg[0] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[1] = Math.abs(heights[i+1][j-1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i+1][j]-heights[i][j]);
grads[i][j] = getMaxGrad(3)/scaling;
i=299; j=299;
tempg[0] = Math.abs(heights[i][j-1]-heights[i][j]);
tempg[1] = Math.abs(heights[i-1][j-1]-heights[i][j])/root2;
tempg[2] = Math.abs(heights[i-1][j]-heights[i][j]);
grads[i][j] = getMaxGrad(3)/scaling;
//grads holds the actual 'D8' gradients and is to be written to
//a file. In order to display greyscale image the values need to be
//weighted up (grads is left unchanged).
//
for (i=0; i<300; i++) {
for (j=0; j<300; j++){
wgrads[i][j] = grads[i][j] * weighting;
}
}
shouldcolourheights=false;
red=1; blue=1; green=1;
imageToPaint = getImage(wgrads);
repaint();
jMenuSave.setEnabled(true);
btnColourH.setEnabled(true);
}
public void paint (Graphics g) {
g.drawImage(imageToPaint, 50, 70, this);
}
/**
* Redraws the height image with colour to represent the gradients.
* @param evt
*/
private void btnColourHActionPerformed(java.awt.event.ActionEvent evt) {
shouldcolourheights=true;
imageToPaint = getImage(heights);
repaint();
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Analyst() {
public void actionPerformed(ActionEvent e) {
throw new UnsupportedOperationException("Not supported yet.");
}
} .setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton btnColourH;
private javax.swing.JButton btnGradients;
private javax.swing.JButton btnHeights;
private javax.swing.JFileChooser fc;
private javax.swing.JMenu jMenu;
private javax.swing.JMenuBar jMenuBar;
private javax.swing.JMenuItem jMenuExit;
private javax.swing.JMenuItem jMenuOpen;
private javax.swing.JMenuItem jMenuSave;
private javax.swing.JPopupMenu.Separator jSeparator;
// End of variables declaration
}
答案 0 :(得分：1)
这是太多的代码无法读取，因为缺少一些类而无法执行。
无论如何，根据您描述的症状，您的主要问题是您覆盖顶级容器的paint方法，而您没有调用super.paint()。
两件事：
paintXXX方法时，请始终调用super.paintXXX() paint的{{1}}，而是扩展JFrame，覆盖其JPanel方法（按照之前的方式自定义绘制）并设置该面板作为paintComponent。答案 1 :(得分：1)
添加super.paint(g)。
@Override
public void paint(Graphics g) {
super.paint(g);
g.drawImage(imageToPaint, 50, 70, this);
}
此外，您可以使用System.arraycopy加快复制速度。
double[] get1DArray(double[][] twoDarray) {
double[] tempArray = new double[twoDarray.length * twoDarray[0].length];
int jdim = twoDarray[0].length;
for (int i = 0; i < twoDarray.length; i++) {
System.arraycopy(twoDarray[i], 0, tempArray, i * jdim, jdim);
}
return tempArray;
}