java - 自动填充组合框系列 - Java

Question

我正在编写一个简单的程序；该程序的一部分是一系列组合框，我在其中输入了月份(alpha)、天(数字)和年(数字)的字符串。我希望以某种方式让 Java 以月、日和年的形式提取日期，然后根据系统时钟自动填充这些组合框，其中包含正确的日期。

这是我的一些代码:

public static final String[] MONTHS = {"January", "February", "March", "April", "May", "June",
                                       "July", "August", "September", "October", "November",
                                       "December"};
public static final String[] DAYS = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", 
                                 "12", "13", "14", "15", "16", "17", "18", "19", "20", 
                                 "21", "22", "23", "24", "25", "26", "27", "28", "29", 
                                 "30", "31"};
public static final String[] YEARS = {"2015", "2014", "2013", "2012", "2011", "2010"};

Note to FORUMS: THIS ISN'T ALL THE CODE. I'VE JUST PROVIDED INFORMATION NECESSARY FOR THE QUESTION.

JLabel start = new JLabel("Start Date:");
if (shouldWeightX) {
c.weightx = .5;
}
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 1;
c.gridwidth = 1;
pane.add(start, c);

JComboBox MonthLong = new JComboBox();
if (shouldWeightX) {
    c.weightx = 0;
    }
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 1;
c.gridy = 1;
c.gridwidth = 1;
for(int i=0; i<MONTHS.length;i++) {
        MonthLong.addItem(MONTHS[i]);
    }
pane.add(MonthLong, c);

JComboBox DayLong = new JComboBox();
if (shouldWeightX) {
    c.weightx = 1.0;
    }
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 2;
c.gridy = 1;
c.gridwidth = 1;
for(int i=0; i<DAYS.length;i++) {
    DayLong.addItem(DAYS[i]);
}
pane.add(DayLong, c);

JComboBox YearLong = new JComboBox();
if (shouldWeightX) {
    c.weightx = 1.0;
    }
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 3;
c.gridy = 1;
c.gridwidth = 1;
for(int i=0; i<YEARS.length;i++) {
    YearLong.addItem(YEARS[i]);
}
YearLong.setSelectedItem("2013");
pane.add(YearLong, c);

提前致谢。

Answer 1

您应该使用 java.util.Calendar 类获取当前时间部分。

Calendar now = Calendar.getInstance();
// months start with 0 
System.out.println("Year is: " + now.get(Calendar.YEAR));   
System.out.println("Month is: " + (now.get(Calendar.MONTH) + 1));
System.out.println("Date is: " + now.get(Calendar.DATE));

然后您可以在初始化步骤中在组合框上设置SelectedIndex。

还请记住，您不必使用 for 循环将这些字符串添加到组合框。就试试吧。

JComboBox<String> MonthLong = new JComboBox<String>(MONTHS);