Objective C - 如何使用initWithCoder方法？ [英] Objective C - How do I use initWithCoder method?

问题描述

我有以下方法为我的类打算加载一个nib文件并实例化对象：

I have the following method for my class which intends to load a nib file and instantiate the object:

- (id)initWithCoder:(NSCoder*)aDecoder 
{
    if(self = [super initWithCoder:aDecoder]) {
        // Do something
    }
    return self;
}

如何实例化这个类的对象？
这是 NSCoder ？如何创建它？

How does one instantiate an object of this class? What is this NSCoder? How can I create it?

    MyClass *class = [[MyClass alloc] initWithCoder:aCoder];

推荐答案

您还需要定义以下方法如下：

You also need to define the following method as follows:

- (void)encodeWithCoder:(NSCoder *)enCoder {
    [super encodeWithCoder:enCoder];

    [enCoder encodeObject:instanceVariable forKey:INSTANCEVARIABLE_KEY];

    // Similarly for the other instance variables.
    ....
}

并且在initWithCoder方法中初始化如下

And in the initWithCoder method initialize as follows:

- (id)initWithCoder:(NSCoder *)aDecoder {

   if(self = [super initWithCoder:aDecoder]) {
       self.instanceVariable = [aDecoder decodeObjectForKey:INSTANCEVARIABLE_KEY];

       // similarly for other instance variables
       ....
   }

   return self;
}

您可以初始化对象标准方式，

You can initialize the object standard way i.e

CustomObject *customObject = [[CustomObject alloc] init];

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