調用方法重新啓動，如果條件滿足，而不使用循環

Question

我正在爲學校的工資計劃工作。我只用了兩週的時間來使用GUI，所以我的技能有很大的發展空間。除了這種方法，一切正常。我試圖得到清除JTextAreas的方法，如果輸入的數字超出範圍並跳過剩餘的代碼發送數據到JTextArea。到目前爲止，如果超出範圍，它會打印出名稱dept和0.00，但我不希望它顯示任何內容，除非它在範圍內。

public void buildAgain() { 

    // declare variables to hold the JTextField input as string 
    String rateStr, hoursStr, firstName, lastName, dept; 


    firstName = (String) fnameField.getText(); 
    lastName = (String) lnameField.getText(); 

    rateStr = rateField.getText(); 
    // convert the rate field into double in order to calculate it 
    rate = Double.parseDouble(rateStr); 


    hoursStr = hoursField.getText(); 
    // convert the hours into double in order to calculate it 
    hoursWorked = Double.parseDouble(hoursStr); 

    // Check how many hours worked to make sure they are within range 
    if(hoursWorked >= 0 && hoursWorked <=60) 
     hours = hoursWorked; 

    // Display message if hours are not within range 
    else 
     JOptionPane.showMessageDialog(null, "You have entered an invalid number of hours. \n" 
          + " Please enter a number between 0 and 60.", "Hour Entry Error", 
          JOptionPane.ERROR_MESSAGE); 

    // Clears JTextFields after the error message 
    fnameField.setText(""); 
    lnameField.setText(""); 
    hoursField.setText(""); 
    rateField.setText(""); 

    // check the hourly rate to make sure it is within range 
    if (rate >= 6 && rate <=150) 
     payRate = rate; 

    // display an error message if rate entered not within range 
    else 
     JOptionPane.showMessageDialog(null, "You have entered an invalid pay rate. \n " 
          + "Please enter the rate between 6 and 150.", "Pay Rate Error", 
          JOptionPane.ERROR_MESSAGE); 

    // clear the JTextFields after error message 
    fnameField.setText(""); 
    lnameField.setText(""); 
    hoursField.setText(""); 
    rateField.setText(""); 

    // calculate the pay regular hours 
    if (hours >= 0 && hours <= 40){ 
     weeklyPay = hours*payRate; 

    // Calculate overtime pay 
    } else if (hours > 40 && hours <= 60){ 
     overTime = (hours-40) * (payRate*1.5); 
     weeklyPay = overTime + (40*payRate); 
    } 

    // Display the total pay in uneditable table 
    totalPayField.setText("$"+dollar.format(weeklyPay)); 

    // Send name to JTextArea 
    list.append(firstName + " "); 
    list.append(lastName); 

    // Get the selected department 
    if(hr.isSelected()) 
     dept = hr.getText(); 
    else if(accounting.isSelected()) 
     dept = accounting.getText();//"Accounting"; 
    else if(marketing.isSelected()) 
     dept = marketing.getText(); 
    else if(sales.isSelected()) 
     dept = sales.getText(); 
    else 
     dept = shipping.getText(); 

    // Send selected department and pay to JTextArea 
    list.append("\t" + dept); 
    list.append("\t$" + dollar.format(weeklyPay) + "\n"); 

    } 

Answer 1

你快到了。

在檢查工作小時的代碼段在範圍之內之前，移動清除JTextFields的代碼段。然後在顯示錯誤信息後立即返回。那樣方法的執行不會繼續。

//Clears JTextFields before checking the error message 
fnameField.setText(""); 
... 

//check how many hours worked to make sure they are within range 
if(hoursWorked >= 0 && hoursWorked <=60) 
    hours = hoursWorked; 

//Display message if hours are not within range 
else 
    JOptionPane.showMessageDialog(null, "error msg.\n", JOptionPane.ERROR_MESSAGE); 
    return 

注意：如果您只希望在出現錯誤後清除字段，請將它們移到顯示錯誤消息的else語句中。

例：

//check how many hours worked to make sure they are within range 
if(hoursWorked >= 0 && hoursWorked <=60) { 
    hours = hoursWorked; 

//Display message if hours are not within range 
} else { 
    JOptionPane.showMessageDialog(null, "error msg.\n", JOptionPane.ERROR_MESSAGE); 
    //Clears JTextFields before checking the error message 
    fnameField.setText(""); 
    ... 
    return 
}