我要激发一个带有复选框和复选框组的菜单的Java小程序，在每种食物选择旁边列出卡路里。我的问题是我无法弄清楚为什么我在编译该错误消息时会不断收到此错误消息:
AnAppletWithCheckboxes.java:188:非法转发引用
int crepeVal = Integer.parseInt(textField.getText());
我得到的每一行都是将textField转换为int，因此有17个错误。任何想法，为什么将不胜感激!
这是我的代码:: 很长，因为有很多复选框和textFields。我注释掉我的错误位置! :
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class AnAppletWithCheckboxes extends Applet implements ItemListener {
public void init() {
setLayout(new GridLayout(1, 0));
CheckboxGroup dinnerType = new CheckboxGroup();
standard = new Checkbox("standard", dinnerType, false);
standard.addItemListener(this);
deluxe = new Checkbox("deluxe", dinnerType, true);
deluxe.addItemListener(this);
CheckboxGroup appetizers = new CheckboxGroup();
crepe = new Checkbox("crepe", appetizers, false);
crepe.addItemListener(this);
quiche = new Checkbox("quiche", appetizers, false);
quiche.addItemListener(this);
dumpling = new Checkbox("dumpling", appetizers, false);
dumpling.addItemListener(this);
textField = new TextField("300");
textField.setEditable(false);
textField2 = new TextField("330");
textField2.setEditable(false);
textField3 = new TextField("98");
textField3.setEditable(false);
CheckboxGroup soupOrSalad = new CheckboxGroup();
soup = new Checkbox("Soup", soupOrSalad, false);
soup.addItemListener(this);
CheckboxGroup soups = new CheckboxGroup();
cream = new Checkbox("cream", soups, false);
cream.addItemListener(this);
broth = new Checkbox("broth", soups, false);
broth.addItemListener(this);
gumbo = new Checkbox("gumbo", soups, false);
gumbo.addItemListener(this);
textField4 = new TextField("190");
textField4.setEditable(false);
textField5 = new TextField("20");
textField5.setEditable(false);
textField6 = new TextField("110");
textField6.setEditable(false);
salad = new Checkbox("Salad", soupOrSalad, false);
salad.addItemListener(this);
CheckboxGroup salads = new CheckboxGroup();
tossed = new Checkbox("tossed", salads, false);
tossed.addItemListener(this);
caesar = new Checkbox("caesar", salads, false);
caesar.addItemListener(this);
croutons = new Checkbox("croutons");
croutons.addItemListener(this);
lite = new Checkbox("lite dressing");
lite.addItemListener(this);
textField7 = new TextField("35");
textField7.setEditable(false);
textField8 = new TextField("90");
textField8.setEditable(false);
textField9 = new TextField("60");
textField9.setEditable(false);
textField10 = new TextField("50");
textField10.setEditable(false);
CheckboxGroup entrees = new CheckboxGroup();
chicken = new Checkbox("chicken", entrees, false);
chicken.addItemListener(this);
beef = new Checkbox("beef", entrees, false);
beef.addItemListener(this);
lamb = new Checkbox("lamb", entrees, false);
lamb.addItemListener(this);
fish = new Checkbox("fish", entrees, false);
fish.addItemListener(this);
textField11 = new TextField("200");
textField11.setEditable(false);
textField12 = new TextField("170");
textField12.setEditable(false);
textField13 = new TextField("65");
textField13.setEditable(false);
textField14 = new TextField("150");
textField14.setEditable(false);
CheckboxGroup deserts = new CheckboxGroup();
pie = new Checkbox("pie", deserts, false);
pie.addItemListener(this);
fruit = new Checkbox("fruit", deserts, false);
fruit.addItemListener(this);
sherbet = new Checkbox("sherbet", deserts, false);
sherbet.addItemListener(this);
textField15 = new TextField("80");
textField15.setEditable(false);
textField16 = new TextField("60");
textField16.setEditable(false);
textField17 = new TextField("107");
textField17.setEditable(false);
calories = new Button("Calories");
calTextField = new TextField("0"+total);
calTextField.setEditable(false);
setLayout(new GridLayout(0, 1));
Panel p = new Panel();
add(p);
p.add(standard);
p.add(deluxe);
appetizerPanel = new Panel();
add(appetizerPanel);
label = new Label("Appetizer");
appetizerPanel.add(label);
appetizerPanel.add(crepe);
appetizerPanel.add(textField);
appetizerPanel.add(quiche);
appetizerPanel.add(textField2);
appetizerPanel.add(dumpling);
appetizerPanel.add(textField3);
soupPanel = new Panel();
add(soupPanel);
soupPanel.add(soup);
soupPanel.add(cream);
soupPanel.add(textField4);
soupPanel.add(broth);
soupPanel.add(textField5);
soupPanel.add(gumbo);
soupPanel.add(textField6);
saladPanel = new Panel();
add(saladPanel);
saladPanel.add(salad);
saladPanel.add(tossed);
saladPanel.add(textField7);
saladPanel.add(caesar);
saladPanel.add(textField8);
saladPanel.add(croutons);
saladPanel.add(textField9);
saladPanel.add(lite);
saladPanel.add(textField10);
entreePanel = new Panel();
add(entreePanel);
label2 = new Label("Entree");
entreePanel.add(label2);
entreePanel.add(chicken);
entreePanel.add(textField11);
entreePanel.add(beef);
entreePanel.add(textField12);
entreePanel.add(lamb);
entreePanel.add(textField13);
entreePanel.add(fish);
entreePanel.add(textField14);
desertPanel = new Panel();
add(desertPanel);
label3 = new Label("Desert");
desertPanel.add(label3);
desertPanel.add(pie);
desertPanel.add(textField15);
desertPanel.add(fruit);
desertPanel.add(textField16);
desertPanel.add(sherbet);
desertPanel.add(textField17);
caloriesPanel = new Panel();
add(caloriesPanel);
caloriesPanel.add(calories);
caloriesPanel.add(calTextField);
}
public void LabelChange(Label b) {
if (b ==label3)
b.setForeground(Color.lightGray);
else
label3.setForeground(Color.black);
}
/*这是我得到那些错误的地方! */
int crepeVal = Integer.parseInt(textField.getText());
int quicheVal = Integer.parseInt(textField2.getText());
int dumplingVal = Integer.parseInt(textField3.getText());
int creamVal = Integer.parseInt(textField4.getText());
int brothVal = Integer.parseInt(textField5.getText());
int gumboVal = Integer.parseInt(textField6.getText());
int tossedVal = Integer.parseInt(textField7.getText());
int caesarVal = Integer.parseInt(textField8.getText());
int croutonsVal = Integer.parseInt(textField9.getText());
int liteVal = Integer.parseInt(textField10.getText());
int chickenVal = Integer.parseInt(textField11.getText());
int beefVal = Integer.parseInt(textField12.getText());
int lambVal = Integer.parseInt(textField13.getText());
int fishVal = Integer.parseInt(textField14.getText());
int pieVal = Integer.parseInt(textField15.getText());
int fruitVal = Integer.parseInt(textField16.getText());
int sherbetVal = Integer.parseInt(textField17.getText());
public boolean action(Event evt, Object whatAction){
if(!(evt.target instanceof Button)){
return false;
}
else {
calorieCount();
return true;
}
}
public void calorieCount () {
if (crepe.getState())
crepeVal += total;
else
crepeVal = 0;
if (quiche.getState())
quicheVal += total;
else
quicheVal = 0;
if (dumpling.getState())
dumplingVal += total;
else
dumplingVal= 0;
if (cream.getState())
creamVal += total;
else
creamVal = 0;
if (broth.getState())
brothVal += total;
else
brothVal = 0;
if (gumbo.getState())
gumboVal += total;
else
gumboVal = 0;
if (tossed.getState())
tossedVal += total;
else
tossedVal = 0;
if (caesar.getState())
caesarVal += total;
else
caesarVal = 0;
if (croutons.getState())
croutonsVal += total;
else
croutonsVal = 0;
if (lite.getState())
liteVal += total;
else
liteVal = 0;
if (chicken.getState())
chickenVal += total;
else
chickenVal = 0;
if (beef.getState())
beefVal += total;
else
beefVal = 0;
if (lamb.getState())
lambVal += total;
else
lambVal = 0;
if (fish.getState())
fishVal += total;
else
fishVal = 0;
if (pie.getState())
pieVal += total;
else
pieVal = 0;
if (fruit.getState())
fruitVal += total;
else
fruitVal = 0;
if (sherbet.getState())
sherbetVal += total;
else
sherbetVal = 0;
}
public void itemStateChanged(ItemEvent e) {
if (e.getSource() == standard || e.getSource() == deluxe)
handleDinnerType((Checkbox)e.getSource());
else if (e.getSource() == soup || e.getSource() == salad)
handleSoupSaladChoice((Checkbox)e.getSource());
}
void handleDinnerType(Checkbox selectedType) {
boolean enabled;
if (selectedType == standard){
enabled = false;
LabelChange(label3);
}
else{
enabled = true;
LabelChange(label);
}
soup.setEnabled(enabled);
salad.setEnabled(enabled);
pie.setEnabled(enabled);
fruit.setEnabled(enabled);
sherbet.setEnabled(enabled);
cream.setEnabled(enabled);
broth.setEnabled(enabled);
gumbo.setEnabled(enabled);
tossed.setEnabled(enabled);
caesar.setEnabled(enabled);
croutons.setEnabled(enabled);
lite.setEnabled(enabled);
}
void handleSoupSaladChoice(Checkbox selectedCourse) {
boolean soupEnabled, saladEnabled;
if (selectedCourse == soup) {
soupEnabled = true;
saladEnabled = false;
soup.setForeground(Color.BLACK);
salad.setForeground(Color.lightGray);
}
else {
soupEnabled = false;
saladEnabled = true;
soup.setForeground(Color.lightGray);
salad.setForeground(Color.BLACK);
}
cream.setEnabled(soupEnabled);
broth.setEnabled(soupEnabled);
gumbo.setEnabled(soupEnabled);
tossed.setEnabled(saladEnabled);
caesar.setEnabled(saladEnabled);
croutons.setEnabled(saladEnabled);
lite.setEnabled(saladEnabled);
}
Label
label, label2, label3;
Panel
appetizerPanel, soupPanel, saladPanel, entreePanel, desertPanel, caloriesPanel;
Checkbox
standard, deluxe,
soup, salad,
crepe, quiche, dumpling,
cream, broth, gumbo,
tossed, caesar,
croutons, lite,
chicken, beef, lamb, fish,
pie, fruit, sherbet;
Button calories;
int total = 0;
TextField
textField, textField2, textField3,
textField4, textField5, textField6,
textField7, textField8, textField9,
textField10, textField11, textField12,
textField13, textField14, textField15,
textField16, textField17, calTextField;
}
最佳答案
在Java中，如果在源代码中的a之前声明了b，则不允许在另一个字段b的初始化程序中引用字段a。也就是说，这是允许的:
int b = 3;
int a = b;
但这是不允许的:
int a = b;
int b = 3;
顺便说一句，如果Java有某种神奇的方法可以确定
textField必须在crepeVal之前初始化，那么您仍然会得到NullPointerException，因为textField在对象构造之后就是null。
关于java - 复选框编译错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8502018/