Xcode 7，Obj-C，“Null传递给需要非空参数的被调用者” [英] Xcode 7, Obj-C, "Null passed to a callee that requires a non-null argument"

问题描述

在Xcode 7中，我收到此警告：

  Null传递给要求非null参数的被调用者
  

..从这个nil初始化一个NSMutableArray ...

$ $ b

  sectionTitles = [[NSMutableArray alloc] initWithObjects：nil]; 
  

我发现我应该使用 removeAllObjects 。

  [sectionTitles removeAllObjects]; 
  

但是，这不允许我评估 sectionTitles.count = = 0 。我尝试 sectionTitles == nil ，但是除非我使用 iniWithObjects 我不能以后添加对象。 p>

当没有记录时，我需要将数组设置为nil或零，当我刷新数据源时。我似乎不能使用 addObject 添加项，除非我使用 initWithObjects 。

解决方案

为什么不尝试：

  sectionTitles = [[NSMutableArray alloc] init]; 
  

或以下任何一种：

  sectionTitles = [[NSMutableArray alloc] initWithCapacity：sectionTitles.count]; 
 sectionTitles = [NSMutableArray new]; 
 sectionTitles = [NSMutableArray array]; 
 sectionTitles = [NSMutableArray arrayWithCapacity：sectionTitles.count]; 
  

可能是一些愚蠢的：

  sectionTitles = [NSMutableArray arrayWithArray：@ []]; 
 sectionTitles = [@ [] mutableCopy]; 
  

有许多方法可以创建空的可变数组。只需阅读文档。

In Xcode 7, I'm getting this warning:

Null passed to a callee that requires a non-null argument

.. from this nil initialization of a NSMutableArray...

    sectionTitles = [[NSMutableArray alloc] initWithObjects:nil];

I've found that I should be using removeAllObjects instead.

    [sectionTitles removeAllObjects];

However, this doesn't allow me to evaluate a sectionTitles.count == 0. I did try sectionTitles == nil, however unless I use iniWithObjects I can't add objects later on.

I need to set the array to nil or zero, when I refresh my datasource, when there's no records. I don't seem to be able to use addObject to add items unless I've used initWithObjects.

解决方案

Why don't you try:

sectionTitles = [[NSMutableArray alloc] init];

or any of the following:

sectionTitles = [[NSMutableArray alloc] initWithCapacity:sectionTitles.count];
sectionTitles = [NSMutableArray new];
sectionTitles = [NSMutableArray array];
sectionTitles = [NSMutableArray arrayWithCapacity:sectionTitles.count];

maybe some silly ones:

sectionTitles = [NSMutableArray arrayWithArray:@[]];
sectionTitles = [@[] mutableCopy];

There are lots of ways to create empty mutable arrays. Just read the doc.

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