java - 初始化对象变量错误

Question

编译以下代码时出错:

class TapeDeck 
{
    boolean canRecord = false;

    void playTape() 
    {
        System.out.println("tape playing");
    }

    void recordTape() 
    {
        System.out.println("tape recording");
    }
}

class TapeDeckTestDrive
{
    public static void main(String [] args)
    {
        TapeDeck t; 
        t.canRecord = true;
        t.playTape();

        if(t.canRecord == true) 
        {
            t.recordTape();
        }
    }
}

错误是:

TapeDeck.java:21: error: variable t might not have been initialized
        t.canRecord = true;
        ^
1 error

如何初始化类中的变量t？

Answer 1

使用new关键字来初始化对象。

TapeDeck t = new TapeDeck();