ios - 调用 NSCash 不起作用
<p><p>我不知道如何使用<code>NSCash</code>,但是我在阅读本主题后尝试过<a href="https://stackoverflow.com/questions/5755902/how-to-use-nscache/12957066#12957066" rel="noreferrer noopener nofollow">How to use NSCache</a>但它没有用。 </p>
<p>我遇到了这个问题<strong>原因:'-:尝试插入 nil 值(键:indexPath)'</strong></p>
<p>我做错了吗?</p>
<pre><code>.h
@interface ViewController : UIViewController
@property (nonatomic, strong) NSMutableArray *jsonArray;
@property (nonatomic, strong) NSMutableArray *jsonArray1;
@property (nonatomic, retain) NSCache *Cache;
</code></pre>
<hr/>
<pre><code>.m
- (void)viewDidLoad
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSData *response = [ initWithContentsOfURL:];
NSError *parseError = nil;
jsonArray = ;
jsonArray1 = [ init];
Cache = [init];
for(int i=0;i<;i++)
{
NSString* city = [ objectForKey:@"city"];
;
}
dispatch_sync(dispatch_get_main_queue(), ^{
self.title = @"İller";
;
jsonArray1 = ;
;
});
});
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>您正在初始化 jsonArray1,就在设置它之前。</p>
<pre><code> jsonArray1 = ; // here jsonArray1 = nil; hence remove this line and run your code again. Yo
; // hence you are setting nil value to this key "indexpath"
</code></pre>
<p>在那个教程中,他们说像</p>
<ul>
<li>要设置值,请使用以下行:</li>
</ul>
<blockquote>
<p>;</p>
</blockquote>
<ul>
<li>要检索值,请使用以下行。当您想使用该缓存值时,应使用此行</li>
</ul>
<blockquote>
<p>jsonArray1 = ;</p>
</blockquote>
<p>在你的情况下,只需评论</p>
<blockquote>
<p>jsonArray1 = ;</p>
</blockquote>
<p>行并再次运行。它不会给出那个错误。</p></p>
<p style="font-size: 20px;">关于ios - 调用 NSCash 不起作用,我们在Stack Overflow上找到一个类似的问题:
<a href="https://stackoverflow.com/questions/18014080/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/18014080/
</a>
</p>
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