我知道之前在此线程中曾问过类似的问题：从另一个类访问 JLabel 但是，当我尝试使用“this.lblNewLabel = new JLabel();”时对于我的代码中的所有 JLabels，但它不起作用。我的问题是，我试图让“MainFrame”中的 JLabels 可供“bananaBreadIngredients”和“ServingsButtons”访问，以便“ServingsButtons”中的操作侦听器可以在“bananaBreadIngredients”中的组件上工作，我需要帮助尝试得到那份工作。如果他们有任何不确定的事情，我会尽力回答有关我的代码的任何问题。
这是我的主要 JFrame 代码（这是我认为最好放置 JLabels 的代码，因为我认为它们能够被其他类（如“bananaBreadIngredients”类）访问）：
package sweets;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
public class MainFrame extends JFrame implements ItemListener {
//all the foods
public int servingNumber = 0;
//ingredient Volumes
public int almondFlourVol = 0;
public int allPurposeFlourVol = 0;
public int unsaltedButterVol = 0;
public int bakingSodaVol = 0;
public int bakingPowderVol = 0;
public int vanillaExtractVol = 0;
public int cocoaPowderVol = 0;
public int saltVol = 0;
public int chocolateChipsVol = 0;
public int instantEspressoVol = 0;
public int vegetableOilVol = 0;
public int bananasVol = 0;
//sugars
public int granulatedSugarVol = 0;
public int powderedSugarVol = 0;
public int lightBrownSugarVol = 0;
//eggs
public int eggsVol = 0;
public int eggWhitesVol = 0;
JLabel granulatedSugar = new JLabel("Granulated Sugar: " + (granulatedSugarVol));
JLabel powderedSugar = new JLabel("Powdered Sugar: " + (powderedSugarVol));
JLabel lightBrownSugar = new JLabel("Light Brown Sugar: " + (lightBrownSugarVol));
JLabel eggs = new JLabel("Eggs: " + (eggsVol));
JLabel eggWhites = new JLabel("Egg Whites: " + (eggWhitesVol));
JLabel bananas = new JLabel("Bananas: " + (bananasVol));
JLabel vegetableOil = new JLabel("Vegetable Oil: " + (vegetableOilVol));
JLabel instantEspresso = new JLabel("Instant Espresso: " + (instantEspressoVol));
JLabel chocolateChips = new JLabel("Chocolate Chips: " + (chocolateChipsVol));
JLabel salt = new JLabel("Salt: " + (saltVol));
JLabel cocoaPowder = new JLabel("Cocoa Powder: " + (cocoaPowderVol));
JLabel vanillaExtract = new JLabel("Vanilla Extract: " + (vanillaExtractVol));
JLabel bakingSoda = new JLabel("Baking Soda: " + (bakingSodaVol));
JLabel unsaltedButter = new JLabel("Unsalted Butter: " + (unsaltedButterVol));
JLabel allPurposeFlour = new JLabel("All-Purpose Flour: " + (allPurposeFlourVol));
JLabel almondFlour = new JLabel("Almond Flour: " + (almondFlourVol));
JLabel bakingPowder = new JLabel("Baking Powder: " + (bakingPowderVol));
String[] food = {bananaBread, brownies, chocolateChipcookies, macarons};
final static String bananaBread = "banana bread";
final static String brownies = "brownies";
final static String chocolateChipcookies = "chocolate chip cookies";
final static String macarons = "macarons";
JPanel ingredients;
private ServingButtons servingButtonsJPanel;
private bananaBreadIngredients bananaBreadIngredientsJPanel;
JPanel browniesIngredients = new JPanel(new BorderLayout());
JPanel cookieIngredients = new JPanel(new BorderLayout());
JPanel macaronIngredients = new JPanel(new BorderLayout());
public MainFrame(){
JPanel recipeName = new JPanel(); //this will have the JComboBox with the foodList
JLabel recipe = new JLabel("Recipes: ");
recipeName.setLayout(new FlowLayout());
recipeName.add(recipe);
JComboBox foodList = new JComboBox(food);
foodList.setEditable(false);
foodList.addItemListener(this);
ingredients = new JPanel(new CardLayout());
//MainFrame.ComboBoxRenderer renderer= new MainFrame.ComboBoxRenderer();
getContentPane().add(foodList, BorderLayout.NORTH);
recipeName.add(foodList);
//Servings buttons
servingButtonsJPanel = new ServingButtons(); //<<-- method call
servingButtonsJPanel.setLayout(new GridLayout(1,1));
//sources used from this: https://stackoverflow.com/questions/29477242/jpanel-and-custom-class-extending-jpanel-not-displaying-correctly
JLabel ingredientLabel = new JLabel("Ingredients Go here: ");
bananaBreadIngredientsJPanel = new bananaBreadIngredients();
ingredients.add(ingredientLabel);
//only works if you add the cards in the same order that they are put in in the array
ingredients.add(bananaBreadIngredientsJPanel, bananaBread );
ingredients.add(browniesIngredients, brownies);
ingredients.add(cookieIngredients, chocolateChipcookies);
ingredients.add(macaronIngredients, macarons);
getContentPane().add(ingredients, BorderLayout.CENTER);
//this will have the dynamically changing ingredients (placeholder: the code for this in the mainIA class but it is not being used as I want to implement it through a class instead of having it in the constructor class like in the mainIA)
JLabel inputRecipe = new JLabel("Input Recipe"); //this will have the input recipe JTextField (placeholder)
this.setTitle("Recipe Portion Calculator");
this.setLayout(new GridLayout(4,1));
this.setSize(800,800);
this.add(recipeName);
this.add(servingButtonsJPanel); //<<-- issue is that I have a GUI in the ServingButtons class but when I call it in the MainFrame class it does not show up in the GUI
this.add(ingredients);
this.add(inputRecipe);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setVisible(true);
}
public void itemStateChanged(ItemEvent evt) {
CardLayout cl = (CardLayout)(ingredients.getLayout());
cl.show(ingredients, (String)evt.getItem());
}
}
这是 ServingsButtons 的类。此类具有应用于不同 JLabels 的增量操作侦听器：
package sweets;
import javax.swing.*;
import java.awt.*;
public class ServingButtons extends JPanel {
public int servingNumber = 0;
//ingredient Volumes
JButton incButton = new JButton("+");
JButton decButton = new JButton(("-"));
public ServingButtons() {
super();
this.setLayout(new GridLayout(1, 4));
//used this code from this Quora Link: https://www.quora.com/How-would-I-get-my-program-to-add-1-every-time-I-press-the-button-%E2%80%9Da%E2%80%9D-in-Java
this.add(new JLabel("Number of Servings: "));
JLabel counterLbl = new JLabel(Integer.toString(servingNumber));
decButton.addActionListener(l -> {
counterLbl.setText(Integer.toString(--servingNumber));
almondFlour.setText("Almound Flour: " + (--almondFlourVol));
granulatedSugar.setText("Granulated Sugar: " + (--granulatedSugarVol));
powderedSugar.setText("Powdered Sugar: " + (--powderedSugarVol));
lightBrownSugar.setText("Light Brown Sugar: " +(--lightBrownSugarVol));
eggs.setText("Eggs: " + (--eggsVol));
eggWhites.setText("Egg Whites: " + (--eggWhitesVol));
bananas.setText("Bananas: " + (--bananasVol));
vegetableOil.setText("Vegetable Oil: " + (--vegetableOilVol));
instantEspresso.setText("Instant Espresso: " + (--instantEspressoVol));
chocolateChips.setText("Chocolate Chips: " + (--chocolateChipsVol));
salt.setText("Salt: " + (--saltVol));
cocoaPowder.setText("Cocoa Powder: " + (--cocoaPowderVol));
vanillaExtract.setText("Vanilla Extract: " + (--vanillaExtractVol));
bakingSoda.setText("Baking Soda: " + (--bakingSodaVol));
unsaltedButter.setText("Unsalted Butter: " + (--unsaltedButterVol));
allPurposeFlour.setText("All-Purpose Flour: " + (--allPurposeFlourVol));
bakingPowder.setText("All-Purpose Flour: " + (--bakingPowderVol));
});
JLabel space = new JLabel("");
this.add(space);
this.add(decButton);
this.add(counterLbl);
incButton.addActionListener(l -> {
counterLbl.setText(Integer.toString(++servingNumber));
granulatedSugar.setText("Granulated Sugar: " + (++granulatedSugarVol));
powderedSugar.setText("Powdered Sugar: " + (++powderedSugarVol));
lightBrownSugar.setText("Light Brown Sugar: " + (++lightBrownSugarVol));
eggs.setText("Eggs: " + (++eggsVol));
eggWhites.setText("Egg Whites: " + (++eggWhitesVol));
bananas.setText("bananas: " + (++bananasVol));
vegetableOil.setText("Vegetable Oil: "+ (++vegetableOilVol));
instantEspresso.setText("instant Espresso: " + (++instantEspressoVol));
chocolateChips.setText("Chocolate Chips: "+ (++chocolateChipsVol));
salt.setText("Salt: " + (++saltVol));
cocoaPowder.setText("Cocoa Powder: " + (++cocoaPowderVol));
vanillaExtract.setText("Vanilla Extract: " + (++vanillaExtractVol));
bakingSoda.setText("Baking Soda: " + (++bakingSodaVol));
unsaltedButter.setText("Unsalted Buttter: " + (++unsaltedButterVol));
allPurposeFlour.setText("All-Purpose Flour: " + (++allPurposeFlourVol));
almondFlour.setText("Almound Flour: " + (++almondFlourVol));
bakingPowder.setText("All-Purpose Flour: " + (++bakingPowderVol));
});
this.add(incButton);
}
}
这是我想要访问 JLabels 的类的代码，以便“ServingsButtons”中的代码适用于此类的代码：
package sweets;
import javax.swing.*;
import java.awt.*;
public class bananaBreadIngredients extends JPanel {
public bananaBreadIngredients(){
super();
this.setLayout(new GridLayout(9,1));
this.add(bananas);
this.add(unsaltedButter);
this.add(granulatedSugar);
this.add(allPurposeFlour);
this.add(bakingSoda);
this.add(salt);
this.add(vanillaExtract);
}
}
任何帮助将不胜感激。谢谢你！