Question

我正在尝试让这个程序打印选择的顶部和外壳，现在它的设置方式，它只打印名称。我尝试将所有字符串初始化为空字符串“”。但无论点击什么按钮，字符串始终为空，即使if语句被要求更改它们。

这是代码

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == output){    
        String str2, str3, str4, str5;
        String str1 = txtName.getText();
        if(e.getSource() == optThick){
            str2  = "thick crust";
        }
        else if (e.getSource() == optThin){
             str2 = "thin crust ";
        }
        if(e.getSource() == cbCheese){
            str3 = "Cheese ";
        }
        if(e.getSource() == cbOlives){
             str4 = "Olives ";
        }
        if(e.getSource() == cbTomatoes){
             str5 = "Tomatoes ";
        }

        textArea.setText("Name : " + str1 + "\n" + "Crust: " + str2 + "\n" + "Toppings: " + str3 + str4 + str5); 
    }
}
}

Answer 1

if(e.getSource() == output){    
       // code omitted 
}

所有if语句都在outer语句中。是吗？

Answer 2

如果有人想知道，这就是我开始工作的方式。

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == output){    
        String str2 = "", str3 = "", str4 = "", str5 = "";
        String str1 = txtName.getText();
        if(optThick.isSelected()){
            str2  = "Thick crust";
        }
        else if (optThin.isSelected()){
             str2 = "Thin crust ";
        }
        if(cbCheese.isSelected()){
            str3 = "Cheese ";
        }
        if(cbOlives.isSelected()){
             str4 = "Olives ";
        }
        if(cbTomatoes.isSelected()){
             str5 = "Tomatoes ";
        }

        textArea.setText(String.format("Name: %s \nCrust: %s\n Toppings: %s%s%s ",str1, str2, str3, str4, str5)); 
    }
}

ActionListener中未初始化的变量

2 个答案: