xcode 将 NSString 写入文件
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write NSString to file
提问by Niels S?nderb?k
I'm trying to write a string to a file and store that in the applicationSupport folder within my app. But my NSLog() statement doesn't log anything in the debugger. I have tried to go through it with the debugger, and i can see that the content is nil, so i'm guessing that's why it's not outputting anything, but i don't know why it's set to nil. Can anybody see my mistake?
我正在尝试将一个字符串写入文件并将其存储在我的应用程序内的 applicationSupport 文件夹中。但是我的 NSLog() 语句没有在调试器中记录任何内容。我试图用调试器来完成它，我可以看到内容为零，所以我猜这就是它不输出任何东西的原因，但我不知道为什么它被设置为零。有人能看到我的错误吗？
NSString *document = [[[[[[[[description stringByAppendingString:@" "]stringByAppendingString:focus]stringByAppendingString:@" "]stringByAppendingString:level]stringByAppendingString:@" "]stringByAppendingString:equipment]stringByAppendingString:@" "]stringByAppendingString:waterDepth];
//NSLog(@"%@", document);
//get the documents directory:
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *supportDirectory = [paths objectAtIndex:0];
//filename
NSString *filename = [NSString stringWithFormat:[_nameTextField.text stringByAppendingString:@".txt"], supportDirectory];
[document writeToFile:filename atomically:NO encoding:NSStringEncodingConversionAllowLossy error:nil];
NSString *content = [[NSString alloc]initWithContentsOfFile:filename usedEncoding:nil error:nil];
NSLog(@"%@", content);
回答by sch
filenameis wrong. It should have the following format: "directory/file.extension". You can use the methods stringByAppendingPathComponentand stringByAppendingPathExtensionto construct such a string.
filename是错的。它应该具有以下格式："directory/file.extension". 您可以使用的方法stringByAppendingPathComponent和stringByAppendingPathExtension构建这样的字符串。
NSString *filename = [supportDirectory stringByAppendingPathComponent:[_nameTextField.text stringByAppendingPathExtension:@"txt"]];
Also, as a side note, the first line should be rewritten using stringWithFormatlike this:
另外，作为旁注，第一行应该stringWithFormat像这样重写：
NSString *document = [NSString stringWithFormat:@"%@ %@ %@ %@ %@", description, focus, level, equipment, waterDepth];
回答by Alex
You have wrong initialize filename. It should be:
你有错误的初始化文件名。它应该是：
NSString *filename = [NSString stringWithFormat:@"%@/%@", supportDirectory,[_nameTextField.text stringByAppendingString:@".txt"]];
it will works! Good luck:)
它会起作用！祝你好运：）
回答by Lefteris
The
这
NSString *filename = [NSString stringWithFormat:[_nameTextField.text stringByAppendingString:@".txt"], supportDirectory];
is wrong. It should be:
是错的。它应该是：
NSString *filename = [NSString stringWithFormat:"%@%@",[_nameTextField.text stringByAppendingString:@".txt"], supportDirectory];
