java - 大小写切换java编译错误

Question

我写了下面的代码但是得到了下面的编译错误:

The local variable dirArrow may not have been initialized. Note that a problem regarding missing 'default:' on 'switch' has been suppressed, which is perhaps related to this problem

//return the ID of the robot and arrow of his facing direction
public String toString(){
    char dirArrow;
    switch (direction) {
        case UP: dirArrow= '^';
        case RIGHT: dirArrow= '>';
        case DOWN: dirArrow= 'V';
        case LEFT: dirArrow= '<';
        break;

    }
    return (Integer.toString(RoboID) + dirArrow);
}

Answer 1

您需要像这样初始化您的 dirArrow 变量:

char dirArrow = ' ';
switch (direction) {

阅读为什么本地 variable should be initialized .

注意:您还需要在每个 case block 的末尾添加一个 break 语句，例如:

case UP: {
    dirArrow= '^';
    break;
}