Variable 'value' is already defined in the scope

这个错误是因为代码中变量 'value' 已经在方法参数中定义过了，而在方法体内部又重新定义了一次，导致产生了冲突。你可以把方法体内部的 'value' 改成另外一个名称，比如 'progress'，如下所示：

private void setProgressValue(int value) {
    if (value < 0) {
        value = 0;
    } else if (value > 100) {
        value = 100;
    }
    progressbar.setProgress(progress); // 更新进度条的值
}

相关问题

name 'year' is not defined

This error message is letting you know that there is no variable or object called "year" that has been defined in your code.

To fix this error, you need to define the variable "year" before you try to use it. For example, you could define the variable by assigning it a value:

year = 2021

Alternatively, if you have already defined the variable but it is not in the scope of the code that is causing the error, you may need to adjust the placement of your code so that the variable is accessible where it is needed.