ios 从文本文件中读取 - 目标 C
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Reading from text file - Objective C
提问by Johnrad
I am trying to familiarize myself with objective C, and my current goal is to read a list of items in a text file and store them in a NSString array.
我正在尝试熟悉目标 C，我目前的目标是读取文本文件中的项目列表并将它们存储在 NSString 数组中。
Currently this is what I have:
目前这是我所拥有的：
NSString *filepath = [[NSBundle mainBundle] pathForResource:@"myList" ofType:@"txt"];
NSData* data = [NSData dataWithContentsOfFile:filepath];
NSString* string = [[NSString alloc] initWithBytes:[data bytes]
length:[data length]
encoding:NSUTF8StringEncoding];
NSString* delimiter = @"\n";
listArray = [string componentsSeparatedByString:delimiter];
I am not sure if this matters, but myList.txtis in my Supporting Files.
我不确定这是否重要，但myList.txt在我的支持文件中。
At the moment, I only have one item in my list. However I am unable to store even that 1 item into my listArray.
目前，我的清单中只有一项。但是，我什至无法将那 1 项存储到我的listArray.
I am sure it is something silly that I am missing, I am just new to Objective C.
我确定我错过了一些愚蠢的事情，我只是 Objective C 的新手。
EDIT:I apologize for not mentioning this earlier. I AM NOT receiving any sort of error. My array is just null.
编辑：我很抱歉没有早点提到这一点。我没有收到任何错误。我的数组只是空的。
回答by DBD
I'm going to suggest a little simplification which might solve your problem since I can't say what your problem is. From the information I'm not sure if you are getting the proper file contents when reading it in or not.
我将建议进行一些简化，这可能会解决您的问题，因为我无法说出您的问题是什么。从这些信息中，我不确定您在读入文件时是否获得了正确的文件内容。
NSString *filepath = [[NSBundle mainBundle] pathForResource:@"myList" ofType:@"txt"];
NSError *error;
NSString *fileContents = [NSString stringWithContentsOfFile:filepath encoding:NSUTF8StringEncoding error:&error];
if (error)
NSLog(@"Error reading file: %@", error.localizedDescription);
// maybe for debugging...
NSLog(@"contents: %@", fileContents);
NSArray *listArray = [fileContents componentsSeparatedByString:@"\n"];
NSLog(@"items = %d", [listArray count]);
回答by ElonChan
If the content of the file is just like:
如果文件的内容是这样的：
[{"Title":"20","Cost":"20","Desc":""},{"Title":"10","Cost":"10.00","Desc":""},{"Title":"5","Cost":"5.00","Desc":""}]
try this
尝试这个
-(id)readFromDocumentDBFolderPath:(NSString *)fileName
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:fileName];
NSFileManager *fileManager=[NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:appFile])
{
NSError *error= NULL;
NSData* data = [NSData dataWithContentsOfFile:appFile];
id resultData = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
if (error == NULL)
{
return resultData;
}
}
return NULL;
}
