ios开发－数据类型转换
1，NSData 与 NSString
NSData --> NSString
NSString*aString = [[NSString alloc] initWithData:adata encoding:NSUTF8StringEncoding];
NSString --> NSData
NSString*aString = @"1234";
NSData*aData = [aString dataUsingEncoding: NSUTF8StringEncoding];
2，NSData 与 Byte
NSData --> Byte
NSString*testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
Byte --> 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数组－>16进制数
Byte *bytes = (Byte *)[aData bytes];
NSString *hexStr=@"";
for(int i=;i<[encryData length];i )
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
NSLog(@"bytes 的16进制数为:%@",hexStr);
16进制数－>Byte数组
///// 将16进制数据转化成Byte 数组
NSString *hexString = @"3e435fab9c34891f"; //16进制字符串
int j=;
Byte bytes[128]; ///3ds key的Byte 数组， 128位
for(int i=;i<[hexString length];i )
{
int int_ch; /// 两位16进制数转化后的10进制数
unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(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]; ///两位16进制数中的第二位(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; ///将转化后的数放入Byte数组里
j ;
}
NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];
NSLog(@"newData=%@",newData);
3，NSData 与 UIImage
NSData --> UIImage
UIImage*aimage = [UIImage imageWithData: imageData];
//例：从本地文件沙盒中取图片并转换为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);
4，NSData 与 NSMutableData
NSData --> MSMutableData
NSData*data=[[NSData alloc]init];
NSMutableData*mdata=[[NSMutableData alloc]init];
mdata=[NSDatadataWithData:data];
5.NSDictionary类型转换为NSData类型：
//NSDictionary -> NSData:
NSDictionary *params = [NSDictionarydictionaryWithObjectsAndKeys: @"balance", @"key", @"remaining balance",@"label", @"45", @"value", @"USD", @"currencyCode",nil];
NSMutableData *data =[[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiveralloc] initForWritingWithMutableData:data];
[archiver encodeObject:paramsforKey:@"Some Key Value"];
[archiver finishEncoding];
6.NSData类型转换为NSDictionary类型：
//NSData -> NSDictionary
NSData *data = [[NSMutableData alloc]initWithContentsOfFile:[self dataFilePath]];
NSKeyedUnarchiver *unarchiver =[[NSKeyedUnarchiver alloc] initForReadingWithData:data];
NSDictionary *myDictionary = [[unarchiverdecodeObjectForKey:@"Some Key Value"] retain];
[unarchiver finishDecoding];[unarchiver release];
[data release];
7: NSData NSArray 转换
NSArray *arr1= [[NSArray alloc]initWithObjects:@"0",@"5",nil]; NSData *data= [NSKeyedArchiver archivedDataWithRootObject:arr1]; NSArray *arr2= [NSKeyedUnarchiver unarchiveObjectWithData:data]; NSLog(@"->%@",[arr1 objectAtIndex:1]); NSLog(@"->%@",[arr2 objectAtIndex:1]);
