簡單資料的讀寫操作

iOS中提供了對一下四種(包括他們的子類)可直接進行檔案存取的操作

• NSString(字串)
• NSArray(陣列)
• NSdictionary(字典)
• NSData(資料)

獲取Document檔案目錄下的檔案路徑

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

字串的存取

儲存一個字串

• 獲取要儲存的檔案路徑

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

• 將一個字串寫入到一個檔案中

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

• 將一個字串歸檔到一個檔案中

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

取出一個字串

• 簡單的讀取

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

• 反歸檔一個字串

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

陣列的存取

儲存一個陣列

• 將一個陣列寫入到檔案中

//建立一個陣列
NSArray *array = @[@"小李",@"小紅",@"Mark"];
[array writeToFile:[self GetThefilePath:@"array.txt"] atomically:YES];

• 將一個陣列歸檔到一個檔案中

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

讀取一個陣列

• 簡單的讀取

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

• 反歸檔一個陣列

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

字典的存取

字典的儲存

• 簡單的寫入

//建立一個字典
NSDictionary *dictionary = @{@"name":@"小紅",@"age":@22,@"sex":@"男"};
[dictionary writeToFile:[self GetThefilePath:@"dictionary.txt"] atomically:YES];

• 將字典歸檔到檔案中

//建立一個字典
NSDictionary *dictionary = @{@"name":@"小紅",@"age":@22,@"sex":@"男"};
[NSKeyedArchiver archiveRootObject:dictionary toFile:[self GetThefilePath:@"dictionary.txt"]];

字典的讀取

• 簡單的讀取

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

• 返歸檔一個字典

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

NSData的存取

NSData的儲存

• 先將一個圖片轉換為NSData格式，然後在進行儲存

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

• 將NSData資料寫入到檔案中

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

• 將NSData資料進行歸檔

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

NSData的讀取

• 從檔案讀取出來的還是一個NSData型別的資料

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

• 反歸檔一個NSData

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