NSArray writeFileToPath失敗

Question

我無法跟蹤將NSDictionary對象數組寫入文件的問題。

NSDictionary對象中的每個鍵都是NSString s，值也是如此。所以數組應該可寫入plist，因爲文檔狀態是必需的。總之，這裏是我的代碼：

BOOL success = [representations writeToFile:[self filePathForCacheWithCacheID:cacheID] atomically:YES]; 
//success is NO 

文件路徑的方法是這樣的：

+ (NSString *)filePathForCacheWithCacheID:(NSString *)cacheID 
{ 
    NSURL *cachesDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject]; 
    return [[cachesDirectory URLByAppendingPathComponent:cacheID] absoluteString]; 
} 

和cacheID是字符串 「對象」。在運行時，filePathForCacheWithCacheID:方法返回像繩子：

file:///Users/MyName/Library/Application%20Support/iPhone%20Simulator/7.0/Applic‌​ations/3A57A7B3-A522-4DCC-819B-DC8DEEDCD041/Library/Caches/objects 

可能是錯誤怎麼回事？

Answer 1

代碼正試圖將文件寫入表示文件URL而不是文件系統路徑的字符串。如果你想使用該方法，其中路徑字符串預期的返回值，你應該path替代absoluteString電話：

+ (NSString *)filePathForCacheWithCacheID:(NSString *)cacheID 
{ 
    NSURL *cachesDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject]; 
    return [[cachesDirectory URLByAppendingPathComponent:cacheID] path]; 
} 

另外，有filePathForCacheWithCacheID:方法返回一個NSURL，然後使用writeToURL:atomically:方法。

+ (NSURL *)fileURLForCacheWithCacheID:(NSString *)cacheID 
{ 
    NSURL *cachesDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject]; 
    return [cachesDirectory URLByAppendingPathComponent:cacheID]; 
} 
... 
BOOL success = [representations writeToURL:[self fileURLForCacheWithCacheID:cacheID] atomically:YES];