预期的类找到对象

Question

ArrayList transactions = new ArrayList<Transaction>();

public void printTransactions() {
    for(Transaction t: transactions)
        System.out.println("Transaction Type: " + t.getType() +
                           "\nDescription: " + t.getDescription() +
                           "\nAmount: " + t.getAmount() +
                           "\nNew Balance: " + t.getBalance() + 
                           "\nDate: " + t.getDate());
}

我是 Java 新手，我花了很长时间试图找出这个错误。在我的printTransactions() 方法中，它说从 for 循环行“错误：需要不兼容的类型的事务找到对象”开始

我尝试将t 转换为事务类Transaction(t).getType()，但这也无济于事。

Answer 1

transactions 声明中缺少泛型类型。试试这个

ArrayList<Transaction> transactions = new ArrayList<Transaction>();