与 PHP 的“变量变量"等效的 Objective C [英] Objective C Equivalent of PHP's "Variable Variables"

问题描述

在 PHP 和 JavaScript 中，您可以通过使用另一个变量作为其名称的一部分来动态使用变量.我不想使用数组作为解决方案的一部分.这可以在目标 C 中实现吗?我想做这样的事情:

In PHP and in JavaScript you can dynamically use a variable by using another variable as part of its name. I do not want to use an array as part of the solution. Can this be achieved in Objective C? I'd like to do something like this:

for (int i=1; i<6; i++) {
        if([appRecord.answer(i) length] != 0){
            self.textView.answer(i)ViewSingle.text = appRecord.answer(i);
        }
}

推荐答案

简短回答:否.

长答案:有点.

1. 您可以使用数组，将变量存储在其中，并对其进行索引.
2. 与 #1 一样，如果您的对象实际上是 UI 元素并且您不想要一大堆 IBOutlets，那么请改用 IBOutletCollection.
3. 您可以使用字典，将变量存储为值，然后按键查找.
4. 您可以将所有变量声明为@property，然后使用[self valueForKey:] 按名称查找它们.
5. 您可以将 ivar 的名称构建为字符串，然后使用类似 object_getInstanceVariable() 直接检索它的值(这类似于#3，除非你不t 必须将其声明为 @property).这过于复杂，而且通常比您实际需要的锤子大得多.
6. 如果您正在处理视图，您可以为每个视图分配一个唯一的标签，然后通过 [superview viewWithTag:aTag] 检索它.我不建议使用这种方法.

1. You can use an array, store your variables in there, and index into it.
2. Like #1, if your objects are actually UI elements and you don't want a whole bunch of IBOutlets, then use an IBOutletCollection instead.
3. You can use a dictionary, store your variables as values, and look them up by key.
4. You can declare all your variables as @property, and then use [self valueForKey:] to look them up by name.
5. You can build the name of the ivar as a string, and then use something like object_getInstanceVariable() to retrieve it's value directly (this is similar to #3, except you don't have to declare it as an @property). This is excessively complicated and is usually a much bigger hammer than you'll actually need.
6. If you're dealing with views, you can assign each view a unique tag and then retrieve it via [superview viewWithTag:aTag]. I do not recommend using this approach.

请注意，这仅适用于实例变量.这不适用于全局/静态变量.

Note that this only works with instance variables. This does not work with global/static variables.

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