iOS笔记之文件读写

最近做的项目中要存储一组图片数据，图片带有name，date等属性，处理办法是讲image图片直接存在沙盒documents文件中，再使用plist文件存储图片属性和image路径。

存入图片：

- (void)savePhotos:(NSArray *)photos {

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *plistPath = [[paths objectAtIndex:] stringByAppendingPathComponent:@"photo_info.plist"];
    NSString *filePath = [[paths objectAtIndex:] stringByAppendingPathComponent:@"Image"];
    NSLog(@"%@", filePath);

    NSFileManager* fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:plistPath]) {
        [fileManager createFileAtPath:plistPath contents:nil attributes:nil];
    }
    if (![fileManager fileExistsAtPath:filePath]) {
        [fileManager createDirectoryAtPath:filePath withIntermediateDirectories:NO attributes:nil error:nil];
    }

    NSMutableArray *savePhotos = [[NSMutableArray alloc] init];

    for (Photo *photo in photos) {
        NSMutableDictionary *info = [[NSMutableDictionary alloc]init];

        NSString *imagePath = [filePath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.jpg", photo.name]];
        [UIImagePNGRepresentation(photo.image)writeToFile:imagePath atomically:YES];
        [info setObject:imagePath forKey:@"ImagePath"];
        [info setObject:photo.name forKey:@"Name"];
        [info setObject:photo.tags forKey:@"Tags"];
        [info setObject:photo.date forKey:@"Date"];

        [savePhotos addObject:info];
    }
    [savePhotos writeToFile:plistPath atomically:YES];
}

读取图片：

- (NSArray *)loadPhotosFromDisk {
    //从本地读取图片
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *plistPath = [[paths objectAtIndex:] stringByAppendingPathComponent:@"photo_info.plist"];

    NSArray *photosArr = [NSArray arrayWithContentsOfFile:plistPath];
    for (NSDictionary *dic in photosArr) {
        Photo *photo = [[Photo alloc] init];
        photo.image = [UIImage imageWithContentsOfFile:[dic valueForKey:@"ImagePath"]];
        photo.name = [dic valueForKey:@"Name"];
        photo.tags = [dic valueForKey:@"Tags"];
        photo.date = [dic valueForKey:@"Date"];
        [self.photos addObject:photo];
    }

    return self.photos;
}