iphone ios5 数据持久化

 

 

 

NSArray 对象保存

NSString *strOne = @"Persistent data1";
 NSString *strTwo = @"Persistent data 2";
 
 NSMutableArray *persistentArray = [[NSMutableArray alloc] init];
 [persistentArray addObject:strOne];
 [persistentArray addObject:strTwo];
 
 
 
 NSArray *filePathArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *filePath =

-          [[filePathArray objectAtIndex:0] stringByAppendingPathComponent:@"mydatas.plist"];
 
 [[NSArray arrayWithObjects:persistentArray,nil] writeToFile:filePath atomically:NO];
 
 //load
 NSMutableArray *saveDataArray = [[NSMutableArray alloc] init];
 if([[NSFileManager defaultManager] fileExistsAtPath:filePath])
  saveDataArray = [NSMutableArray arrayWithContentsOfFile:filePath];  
 else
  saveDataArray = [NSMutableArray arrayWithContentsOfFile:[[NSBundle

-                  mainBundle] pathForResource:@"Savedatas" ofType:@"plist"]];

-          
 NSArray *strArray = [saveDataArray objectAtIndex:0];
 
 NSString *UnstrOne = [strArray objectAtIndex:0];
 NSString *UnstrTwo = [strArray objectAtIndex:1];

 

 

 

nsstring对象保存

 

NSData *dataToWrite = [[NSString stringWithString:@"String to write"] dataUsingEncoding:NSUTF8StringEncoding];

NSString *docsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *path = [docsDirectory stringByAppendingPathComponent:@"fileName.txt"];

// Write the file
[dataToWrite writeToFile:path encoding:NSUTF8StringEncoding error:nil];

// Read the file
NSString *stringFromFile = [[NSString alloc] initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];

// Check if file exists
NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager fileExistsAtPath:path]; // Returns a BOOL    

// Remove the file
[fileManager removeItemAtPath:path error:NULL];

// Cleanup
[stringFromFile release];
[fileManager release];