iOS NSDictionary、NSData、JSON等 資料類型相互轉換

標籤：

 

1.NSDictionary類型轉換為NSData類型：

1. NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:  
2.                                 @"balance", @"key",  
3.                                @"remaining balance", @"label",  
4.                                 @"45", @"value",  
5.                                 @"USD", @"currencyCode",nil];  
6.            
7. NSMutableData *data = [[NSMutableData alloc] init];  
8. NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];  
9. [archiver encodeObject:params forKey:@"Some Key Value"];  
10. [archiver finishEncoding]; 

2.NSData類型轉換為NSDictionary類型：

1. //NSData -> NSDictionary  
2. NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]];  
3. NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];  
4. NSDictionary *myDictionary = [[unarchiver decodeObjectForKey:@"Some Key Value"] retain];  
5. [unarchiver finishDecoding];  
6. [unarchiver release];  
7. [data release]; 

3.NSDictionary類型轉換為JSON資料類型：

1. //NSDictionary -> JSON:  
2. NSString *jsonStr=[dict JSONRepresentation];

注意JSON與NSDictionary類型的轉換一般會用到第三方公開的JSON庫，讀者可以在網上找到很多。

1. NSData 與 NSString
NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:adata encoding:NSUTF8StringEncoding];

NSString－>NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

 

2.NSData 與 Byte
NSData－> Byte數組
NSString *testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
for(int i=0;i<[testData length];i++)
printf("testByte = %d\n",testByte[i]);

 

Byte數組－> NSData
Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

Byte數組－>16進位數
Byte *bytes = (Byte *)[aData bytes];
NSString *[email protected]"";
for(int i=0;i<[encryData length];i++)
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff]; ///16進位數
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
NSLog(@"bytes 的16進位數為:%@",hexStr);

 

16進位數－>Byte數組
///// 將16進位資料轉化成Byte 數組
NSString *hexString = @"3e435fab9c34891f"; //16進位字串
int j=0;
Byte bytes[128]; 

 

 ///3ds key的Byte 數組， 128位

for(int i=0;i<[hexString length];i++)

{

int int_ch;  /// 兩位16進位數轉化後的10進位數

unichar hex_char1 = [hexString characterAtIndex:i]; ////兩位16進位數中的第一位(高位*16)
int int_ch1;
if(hex_char1 >= ‘0‘ && hex_char1 <=‘9‘)
int_ch1 = (hex_char1-48)*16;   //// 0 的Ascll - 48
else if(hex_char1 >= ‘A‘ && hex_char1 <=‘F‘)
int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65
else
int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97
i++;
 
unichar hex_char2 = [hexString characterAtIndex:i]; ///兩位16進位數中的第二位(低位)
int int_ch2;
if(hex_char2 >= ‘0‘ && hex_char2 <=‘9‘)
int_ch2 = (hex_char2-48); //// 0 的Ascll - 48
else if(hex_char1 >= ‘A‘ && hex_char1 <=‘F‘)
int_ch2 = hex_char2-55; //// A 的Ascll - 65
else
int_ch2 = hex_char2-87; //// a 的Ascll - 97

 

int_ch = int_ch1+int_ch2;

NSLog(@"int_ch=%d",int_ch);

bytes[j] = int_ch;  ///將轉化後的數放入Byte數組裡

j++;

}

NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];

NSLog(@"newData=%@",newData);

 

3. NSData 與 UIImage

NSData－>UIImage

UIImage *aimage = [UIImage imageWithData: imageData];

 

//例：從本地檔案沙箱中取圖片並轉換為NSData

NSString *path = [[NSBundle mainBundle] bundlePath];

NSString *name = [NSString stringWithFormat:@"ceshi.png"];

NSString *finalPath = [path stringByAppendingPathComponent:name];

NSData *imageData = [NSData dataWithContentsOfFile: finalPath];

UIImage *aimage = [UIImage imageWithData: imageData];

 

UIImage－> NSData

NSData *imageData = UIImagePNGRepresentation(aimae);

 

iOS NSDictionary、NSData、JSON等 資料類型相互轉換