iOS中的[Class new]和[Class alloc] init]有什么区别?(复制)

Possible Duplicate:
alloc, init, and new in Objective-C

可能的重复:alloc, init，以及Objective-C中的new

I am a little confused about [Class new] and [[Class alloc] init]. I have defined an object content using [Class new] and [[Class alloc] init].

我对[Class new]和[Class alloc] init]有点困惑。我已经使用[Class new]和[[Class alloc] init]定义了一个对象内容。

(1). NSMutableArray *content = [NSMutableArray new];
(2). NSMutableArray *content = [[NSMutableArray alloc] init];

My question is about the differences between [Class new] and [[Class alloc] init]. For me, (1) and (2) are similar. If (1) and (2) are similar, then why do we use [[Class alloc] init] most of the time, compared to [Class new]? I think that there must be some difference.

我的问题是关于[Class new]和[Class alloc] init]之间的区别。对我来说，(1)和(2)是相似的。如果(1)和(2)是相似的，那么为什么我们大多数时候使用[Class alloc] init]，而不是[Class new]?我想一定有什么不同。

Kindly explain the differences, pros & cons of both?

请解释一下两者的区别、优缺点。

3 个解决方案

#1

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Alloc : Class method of NSObject. Returns a new instance of the receiving class.

Alloc: NSObject的类方法。返回接收类的新实例。

Init : Instance method of NSObject. Implemented by subclasses to initialize a new object (the receiver) immediately after memory for it has been allocated.

Init: NSObject的实例方法。由子类实现，用于在为新对象分配内存之后立即初始化新对象(接收方)。

New : Class method of NSObject. Allocates a new instance of the receiving class, sends it an init message, and returns the initialized object.

新:NSObject的类方法。分配接收类的一个新实例，向它发送一个init消息，并返回初始化的对象。

Release : Instance method of NSObject delegate. Decrements the receiver’s reference count.

Release: NSObject委托的实例方法。降低接收机的参考计数。

Autorelease : Instance method of NSObject delegate. Adds the receiver to the current autorelease pool.

Autorelease: NSObject委托的实例方法。将接收器添加到当前的自动发送池中。

Retain: Instance method of NSObject delegate. Increments the receiver’s reference count.

Retain: NSObject委托的实例方法。增加接收者的参考计数。

Copy : Instance method of NSObject delegate. Returns a new instance that’s a copy of the receiver.

拷贝:NSObject委托的实例方法。返回一个新实例，该实例是接收方的副本。

So to conclude we can say that

总结一下，我们可以说

alloc goes with init

分配和初始化

new = alloc + init

新= alloc + init

#2

The +new method is simply shorthand for +alloc and -init. The ownership semantics are identical. The only benefit to using +new is that it is more concise. If you need to provide arguments to the class's initialiser, you will have to use the +alloc and -initWith... methods instead.

+新方法是+alloc和-init的简写。所有权语义是相同的。使用+new的唯一好处是它更简洁。如果需要向类的初始化器提供参数，则必须使用+alloc和-initWith…而不是方法。

#3

Here: alloc, init, and new in Objective-C

这里是alloc init和Objective-C中的new

Basically it's a question of modern versus traditional. The most direct advantage of init over new is that there are many custom init methods.

基本上这是一个现代与传统的问题。init比new最直接的优点是有许多自定义的init方法。

#1

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