如何检测变量是否已更改? [英] How to detect if a variable has changed?

问题描述

我发现自己仅在变量已更改的情况下才想在程序中执行某些操作.到目前为止，我一直在做这样的事情:

I have found myself wanting to do certain things in my programs only if a variable has changed. I have so far been doing something like this:

int x = 1;
int initialx = x;

...//code that may or may not change the value of x

if (x!=initialx){
    doOneTimeTaskIfVariableHasChanged();
    initialx = x; //reset initialx for future change tests
}  

是否有更好/更简单的方法?

Is there a better/simpler way of doing this?

推荐答案

由于您只想在值更改时才查找并执行某些操作，因此我将使用setXXX，例如:

Since you want to find and perform some action only if the value changes, I would go with setXXX, for example:

public class X
{
    private int x = 1;

    //some other code here

    public void setX(int proposedValueForX)
    {
       if(proposedValueForX != x)
       {
           doOneTimeTaskIfVariableHasChanged();
           x = proposedValueForX;
       }
    }
}

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