objective-c writeToFile不在iPad上，在模拟器上

Question

我已经看到writeToFile不能用于非对象的解释， 但是，这段代码显示iPad上的工作方式存在严重的缺陷设备 以及模拟器如何工作。

NSMutableArray *arrayOne = [NSMutableArray arrayWithObjects:@"Thing One", @"Thing Two", @"Thing Three", nil]; 
[arrayOne writeToFile:@"myLocalMovieMetaData-v11" atomically:YES]; 
NSLog(@"cancelNowButton Test Metadata File Written."); 
NSMutableArray *arrayTwo = [NSMutableArray arrayWithContentsOfFile:@"myLocalMovieMetaData-v11"]; 
NSLog(@"arrayOne: %@",arrayOne); 
NSLog(@"arrayTwo: %@",arrayTwo); //this prints on simulator but not the device. 

Answer 1

应用程序只具有写权限的Documents目录：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"myLocalMovieMetaData-v11"]; 

然后使用：

[arrayOne writeToFile:path atomically:YES];