简单数据的读写操作

iOS中提供了对一下四种(包括他们的子类)可直接进行文件存取的操作

• NSString(字符串)
• NSArray(数组)
• NSdictionary(字典)
• NSData(数据)

获取Document文件目录下的文件路径

- (NSString *)GetThefilePath:(NSString *)filePath{
    NSString *Path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, 
NSUserDomainMask, YES)firstObject]stringByAppendingPathComponent:filePath];
    return Path;
}

字符串的存取

存储一个字符串

• 获取要存储的文件路径

NSString *filePath = [self GetThefilePath:@"name.plist"];

• 将一个字符串写入到一个文件中

NSString *name = @"蓝欧科技";
[name writeToFile: filePath atomically:YES encoding:NSUTF8StringEncoding error:NULL];

• 将一个字符串归档到一个文件中

NSString *name = @"蓝欧科技";
[NSKeyedArchiver archiveRootObject:name toFile:[self GetThefilePath:@"name1.plist"]];

取出一个字符串

• 简单的读取

NSString *string = [NSString stringWithContentsOfFile:
[self GetThefilePath:@"name.plist"] encoding:NSUTF8StringEncoding error:NULL];

• 反归档一个字符串

NSString *string = [NSKeyedUnarchiver unarchiveObjectWithFile:[self GetThefilePath:@"name1.plist"]];

数组的存取

存储一个数组

• 将一个数组写入到文件中

//创建一个数组
NSArray *array = @[@"小李",@"小红",@"Mark"];
[array writeToFile:[self GetThefilePath:@"array.txt"] atomically:YES];

• 将一个数组归档到一个文件中

NSArray *array = @[@"小李",@"小红",@"Mark"];
[NSKeyedArchiver archiveRootObject:array toFile:[self GetThefilePath:@"array.txt"]];

读取一个数组

• 简单的读取

NSArray *array_1 = [NSArray arrayWithContentsOfFile:[self GetThefilePath:@"array.txt"]];

• 反归档一个数组

NSArray *array_2 = [NSKeyedUnarchiver unarchiveObjectWithFile:[self GetThefilePath:@"array.txt"]];

字典的存取

字典的存储

• 简单的写入

//创建一个字典
NSDictionary *dictionary = @{@"name":@"小红",@"age":@22,@"sex":@"男"};
[dictionary writeToFile:[self GetThefilePath:@"dictionary.txt"] atomically:YES];

• 将字典归档到文件中

//创建一个字典
NSDictionary *dictionary = @{@"name":@"小红",@"age":@22,@"sex":@"男"};
[NSKeyedArchiver archiveRootObject:dictionary toFile:[self GetThefilePath:@"dictionary.txt"]];

字典的读取

• 简单的读取

NSDictionary *dictionary_1 = [NSDictionary dictionaryWithContentsOfFile:
[self GetThefilePath:@"dictionary.txt"]];

• 返归档一个字典

NSDictionary *dictionary_2 = [NSKeyedUnarchiver unarchiveObjectWithFile:
[self GetThefilePath:@"dictionary.txt"]];

NSData的存取

NSData的存储

• 先将一个图片转换为NSData格式，然后在进行存储

NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"4.png"]);

• 将NSData数据写入到文件中

[imageData writeToFile:[self GetThefilePath:@"image.txt"] atomically:YES];

• 将NSData数据进行归档

[NSKeyedArchiver archiveRootObject:imageData toFile:[self GetThefilePath:@"image.txt"]];

NSData的读取

• 从文件读取出来的还是一个NSData类型的数据

NSData *imageData_1 = [NSData dataWithContentsOfFile:[self GetThefilePath:@"image.txt"]];

• 反归档一个NSData

NSData *imageData_1 = [NSKeyedUnarchiver unarchiveObjectWithFile:[self GetThefilePath:@"image.txt"]];