plist 读取＋数组排序

一个简单的例子，主要练习数据的永久存储和数组排序 ，用到了一些东西，贴一部分关键代码出来
后面给出完整的附件，把1.plist 添加到模拟器的目录去。
//从plist中读取数据
    NSString *path =[self dataFilePath];
    NSMutableArray *array=[[NSMutableArray  alloc] initWithContentsOfFile:path];
    self.recordsArray=array;
    [array release];

-(void) addrecords:(id)sender
{
    //获取填写内容
    NSString* titletext=inputTextField.text;
    //获取当前时间
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"YY年MM月dd日HH点:mm分:ss秒"];
    NSString* result = [dateFormatter stringFromDate:[NSDate date]];
    [dateFormatter release];
    dateFormatter=nil;

    NSMutableDictionary *newdictionary=[[NSMutableDictionary alloc]init];
    [newdictionary setObject:titletext forKey:@"content"];
    [newdictionary setObject:result forKey:@"datetime"];

    /* 在数组的末尾附加*/
    [self.recordsArray addObject:newdictionary];

    /* save */
    BOOL success = [self.recordsArray writeToFile:[self dataFilePath] atomically:NO];
    NSLog(@"success = %d",success);

    /* reload date */
    [self.recordsArray removeAllObjects];

    NSString *path =[self dataFilePath];
    NSLog(@"path = %@",path);

    NSMutableArray *tempMutableArray = [NSMutableArray arrayWithContentsOfFile:path];
    [self.recordsArray addObjectsFromArray:tempMutableArray];
    NSLog(@"self.recordsArray = %@",self.recordsArray);
    inputTextField.text=@"";
    [recordsTableView reloadData];
}


-(void) sortByName
{
    NSSortDescriptor *sorter = [[NSSortDescriptor alloc] initWithKey:@"content" ascending:YES];
    self. recordsArray = [self.recordsArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:sorter]];
    [self.recordsArray writeToFile:[self dataFilePath] atomically:NO];

    NSString *path =[self dataFilePath];
    NSMutableArray *array=[[NSMutableArray alloc] initWithContentsOfFile:path];
    self.recordsArray=array;
    [array release];
    [recordsTableView reloadData];
}