在一个使用GridBagLayout布局的容器中,一个组件的GridBagConstraints对象设置了`gridx = 1`, `gridy = 2`, `gridwidth = 2`, `gridheight = 1`, `fill = GridBagConstraints.HORIZONTAL`, `weightx = 1.0`, `weighty = 0.0`。如果容器的大小水平方向扩大,但垂直方向不变,那么该组件的实际显示效果将是:

答案解析

本题考察GridBagConstraints的综合运用。选项A正确,`gridwidth` 和 `gridheight` 确定了组件占据的网格单元数,一旦指定,不会随着容器大小改变而改变。`fill = GridBagConstraints.HORIZONTAL` 确保组件在水平方向填充网格单元,而 `weightx = 1.0` 确保在水平方向上的额外空间被分配给该组件。 `weighty = 0.0` 意味着垂直方向不会分配额外的空间,因此高度不变。选项B错误,高度不会因容器水平扩大而增加。选项C错误,网格单元数不会增加,`gridwidth` 已固定为2。选项D错误,`weightx=1.0`和`fill`属性会使得组件宽度增加。
正确答案:A
随机推荐

在如下Java代码片段中,`Bank`类定义了`deposit`和`withdraw`方法,其中`withdraw`方法可能会抛出自定义异常`BankException`。在`operate`方法中,如果先执行两次`deposit`操作,再执行两次`withdraw`操作,若初始账户余额为0,且两次`withdraw`操作分别尝试取款500和1000,则程序运行的结果会是什么? ```java class BankException extends Exception { public BankException(String message) { super(message); } } class Bank { private double balance; public Bank(double initialBalance) { this.balance = initialBalance; } public double getBalance() { return balance; } public void setBalance(double balance) { this.balance = balance; } public void deposit(double amount) { this.setBalance(this.getBalance() + amount); System.out.println("存款金额:"+amount+",现有余额:"+this.getBalance()); } public double withdraw(double amount) throws BankException { if (amount <= this.getBalance()) { this.setBalance(this.getBalance() - amount); System.out.println("取款金额:" + amount + ",现有余额:" + this.getBalance()); } else { BankException be = new BankException("余额不足,操作失败!"); throw be; } return this.getBalance(); } } public class Main { public static void main(String[] args) { try { operate(); } catch (BankException e) { System.err.println(e.getMessage()); } } public static void operate() throws BankException { Bank bank = new Bank(0); bank.deposit(300); bank.deposit(500); bank.withdraw(500); bank.withdraw(1000); System.out.println("任务完成!"); } } ```

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