objective-c iPhone-int 到 NSData？
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iPhone - int to NSData?
提问by bpapa
I'm making an iPhone app where I want to save state of the Application. This includes an int property which I'm persisting to a file on its own. I have it written and working, but I know the way I did it was a bit hacky, converting the int to a String and then NSData. Can anybody suggest a better way?
我正在制作一个 iPhone 应用程序，我想在其中保存应用程序的状态。这包括一个 int 属性，我将它自己持久化到一个文件中。我已经编写并运行了它，但我知道我这样做的方式有点笨拙，将 int 转换为 String 然后转换为 NSData。有人可以提出更好的方法吗？
int someInt = 1;
NSString *aString = [NSString stringWithFormat:@"%d",someInt];
NSData *someData = [aString dataUsingEncoding:NSUTF8StringEncoding];
[someData writeToFile:[documentsDirectory stringByAppendingString:@"someFile"] atomically:YES];
And then reading it from disk and putting it back into an int -
然后从磁盘读取它并将其放回 int -
NSData* someData = [NSData dataWithContentsOfFile:[documentsDirectory stringByAppendingString:@"someFile"]];
NSString *aString = [[NSString alloc] initWithData:someData encoding:NSUTF8StringEncoding];
int someInt = [aString intValue];
回答by Benjamin Pollack
To write:
来写：
int i = 1;
NSData *data = [NSData dataWithBytes: &i length: sizeof(i)];
[data writeToFile: [documentsDirectory stringByAppendingString: @"someFile"] atomically: YES]
and to read back:
并回读：
NSData *data = [NSData dataWithContentsOfFile: [documentsDirectory stringByAppendingString: @"someFile"]];
int i;
[data getBytes: &i length: sizeof(i)];
However, you really should be using NSUserDefaultsfor something like this, in which case you'd be doing:
但是，你真的应该使用这样NSUserDefaults的东西，在这种情况下你会做：
[[NSUserDefaults standardUserDefaults] setInteger: i forKey: @"someKey"]
to write, and
写，和
int i = [[NSUserDefaults standardUserDefaults] integerForKey: @"someKey"];
to read.
阅读。
