简单数据的存储
1. 获取沙盒的位置
NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
也可以使用
NSString *homePath = NSHomeDirectory();
NSString *documentPath2 = [homePath stringByAppendingPathComponent:@"Documents"];
2. 简单数据的存储
2.1 NSString
(1)创建txt文件
NSString *str = @"ADC";
NSString *strFilePath = [documentPath stringByAppendingPathComponent:@"str.txt"];
(2)写入数据
[str writeToFile:strFilePath atomically:YES];
(3)读取数据
NSString *readStr = [[NSString alloc] initWithContentsOfFile:strFilePath encoding:NSUTF8StringEncoding error:nil];
2.2 NSArray
//先创建一个存储array对象的txt文件路径
NSString *arrPath = [documentPath stringByAppendingPathComponent:@"array.txt"];
//使用字面量创建Array
NSArray *nameArr = @[];
//将数据写入txt文件路径
[nameArr writeToFile:arrPath atomically:YES];
//从路径读取出数据
NSArray *arr = [NSArray arrayWithContentsOfFile:arrPath];
2.3 字典
//字典的处理步骤同NSArray
NSString *dictPath = [documentPath stringByAppendingPathComponent:@"dict.txt"];
NSDictionary *dict = @{};
[dict writeToFile:dictPath atomically:YES];
NSDictionary *readDict = [NSDictionary dictionaryWithContentsOfFile:dictPath];
2.4 NSData
NSString *imgPath = [documentPath stringByAppendingPathComponent:@"img.txt"];
UIImage *image = [UIImage imageNamed:@"address"];
//将图片转换成NSData类型
NSData *imgData = UIImagePNGRepresentation(image);
[imgData writeToFile:imgPath atomically:YES];
//读取图片
UIImage *img = [UIImage imageWithContentsOfFile:imgPath];
2.5 从资源包读取图片
//获取绝对路径
NSString *imagePath = [[NSBundle mainBundle] pathForResource:@"address" ofType:@"png"];
//通过路径加载图片
UIImage *image1 = [UIImage imageWithContentsOfFile:imagePath];
imageView.image = image1;
[self.view addSubview:imageView];
UIView *view = [[NSBundle mainBundle] loadNibNamed:@"a" owner:self options:nil][0];
数据,文件操作
- 声明文件的路径
NSString *documentPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
- 创建txt文件及其路径
NSString *filePath = [documentPath stringByAppendingPathComponent:@"file.txt"];
- 创建FileManager,并初始化文件
NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager createFileAtPath:filePath contents:strData attributes:nil];
- 读取数据
NSData *readStrData = [fileManager contentsAtPath:filePath];
NSString *str1 = [[NSString alloc] initWithData:readStrData encoding:NSUTF8StringEncoding];
- 移动文件
5.1 创建目标文件的路径
NSString *moveFilePath = [topath stringByAppendingPathComponent:@"file.txt"];
5.2 移动文件
[fileManager moveItemAtPath:filePath toPath:moveFilePath error:nil];
- 复制文件
NSString *copyPath = [documentPath stringByAppendingPathComponent:@"备份/copy.txt"];
[fileManager createDirectoryAtPath:[copyPath stringByDeletingLastPathComponent] withIntermediateDirectories:YES attributes:nil error:nil];
[fileManager copyItemAtPath:moveFilePath toPath:copyPath error:nil];
- 获取文件信息(文件大小)
NSDictionary *dic = [fileManager attributesOfItemAtPath:filePath error:nil];
NSInteger fileLength = [dic[NSFileSize] integerValue];
- 判断文件是否存在
[fileManager fileExistsAtPath:filePath]
使用NSFileHandle操作文件
//先通过fileManager创建文件并在里面写入内容
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
NSString *filePath = [documentPath stringByAppendingPathComponent:@"file.txt"];
[fileManager createFileAtPath:filePath contents:[@"abc" dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
修改内容
NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:filePath];
//查找到文件最末端
[fileHandle seekToEndOfFile];
[fileHandle writeData:[@"123" dataUsingEncoding:NSUTF8StringEncoding]];
[fileHandle closeFile];
读取文件
NSFileHandle *readFileHandle = [NSFileHandle fileHandleForReadingAtPath:filePath];
//读取长度
NSUInteger length = [[readFileHandle availableData] length];
//设置偏移位置
[readFileHandle seekToFileOffset:length/2];
//从偏移位置开始读取到文件末尾
NSData *readData = [readFileHandle readDataToEndOfFile];
NSString *readStr = [[NSString alloc] initWithData:readData encoding:NSUTF8StringEncoding];
复制文件
NSString *copypath = [documentPath stringByAppendingPathComponent:@"copy.txt"];
[fileManager createFileAtPath:copypath contents:nil attributes:nil];
//打开文件准备写入
NSFileHandle *copyHandle = [NSFileHandle fileHandleForWritingAtPath:copypath];
//writeData会直接覆盖原来的
[copyHandle writeData:readData];
[copyHandle closeFile];
文件的归档与反归档
要进行归档, 必须先让类继承<NSCoding>并实现两个方法
//反序列化
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
self = [super init];
if (self) {
self.name = [aDecoder decodeObjectForKey:@"name"];
self.age = [aDecoder decodeIntegerForKey:@"age"];
}
return self;
}
//序列化
- (void)encodeWithCoder:(NSCoder *)aCoder {
[aCoder encodeObject:self.name forKey:@"name"];
[aCoder encodeInteger:self.age forKey:@"age"];
}
归档过程:Person对象-->NSData-->writeFile
NSMutableData *mulData = [NSMutableData data];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:mulData];
[archiver encodeObject:person forKey:@"Person"];
[archiver finishEncoding];
写入文件
NSString *personDataPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/person.txt"];
[mulData writeToFile:personDataPath atomically:YES];
反归档过程: 从文件里面读取-->NSData-->Person对象
NSData *personData = [NSData dataWithContentsOfFile:personDataPath];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:personData];
Person *person1 = [unarchiver decodeObjectForKey:@"Person"];
NSLog(@"perosn1 = %@", person1);
另外,还有一个系统单利类可以进行数据存储
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:@"123" forKey:@"userName"];
