Object-c data type conversion NSData turn Nsstring,byte,uiimage

NSString converted to a Unicode String: (nsstring*) fname = @ "Test"; char fnamestr[10];memcpy (FNAMESTR, [fname cstringusingencoding:nsunicodestringencoding], ([fname length]));

Compared to strcpy, memcpy is not going to end up with ' n ', but will definitely copy the nth bytes

nsstring Conversion to char * NSString * str= @ "Test"; const char * a =[STR utf8string];

3.char * converted to NSString

NSString *str=[nsstring stringwithcstring  encoding:nsutf8stringencoding];

char * Conversion NSData method One:   char * a = (char*) malloc (sizeof (byte) *16);   NSData *data = [NSData datawithbytes:a   Length:strlen (a)]; method Two:    convert to NSString:-(ID) initwithutf8string: (const char *) bytes    nsdata Conversion char *  nsdata data;  nsdata conversion nsstring;

nsdata* data;

nsstring* astr= [NSString alloc] Initwithdata:data encoding:nsasciistringencoding];

nsstring Transforming NSData Objects nsdata* xmlData = [@ "testdata" datausingencoding:nsutf8stringencoding];

NSString Conversion Nsurl  

Nsurl *url = [Nsurl urlwithstring:[str   stringbyaddingpercentescapesusingencoding:nsutf8stringencoding];

NSString *urlstring=[@ "http://www.google.com/search?client=safari&rls=en&q= Search &ie=utf-8&oe=utf-8 [Stringbyaddingpercentescapesusingencoding:nsutf8stringencoding];

Nsurl Conversion NSString

Nsurl *url=[nsurl urlwithstring:urlstring];

NSString *s=[[url absolutestring] stringbyreplacingpercentescapesusingencoding:nsutf8stringencoding];

Nsarray *arr = [urlstr componentsseparatedbystring:@ "&"]; Nsurl *url = [Nsurl Urlwithstring:[[arr objectatindex:0] stringbyaddingpercentescapesusingencoding: Nsutf8stringencoding]]; Nsmutableurlrequest *request = [Nsmutableurlrequest Requestwithurl:url]; [Request sethttpmethod:@ "POST"];

Nsmutablearray *_array = [[Nsmutablearray alloc] initwithcapacity:0]; for (int i = 1; i < [arr count]; ++i) {NSString *str = [arr objectatindex:i]; [_array ADDOBJECT:STR]; } [_array componentsjoinedbystring:@ "&"]; NSData *data = [[_array componentsjoinedbystring:@ ' &] datausingencoding:nsasciistringencoding]; [Request Sethttpbody:data];

//Send request and get server feedback data nsdata *urldata = [Aesencdecviewcontroller Get:url];    The first conversion of NSData data to char* string char * test = (char*) [urldata bytes]; std::string old = Deaes (test);

//Second conversion nsdata to UTF8 encoded nsstring to char* string
//NSString *desstr = [[NSString alloc] Initwithdata:urldata encoding:nsutf8stringencoding];
//const char *desresult = [Desstr utf8string];
//std::string old = Deaes (Desresult);
    
//Decrypt Word string to clear text
nsstring *oldstr = [[NSString alloc] InitWithCString:old.c_str ()];

Many times the software read the Chinese page encoding set is gb2312, so the display is garbled. You need to convert the NSString text encoding

 2 nsdata *data = [NSData Datawithcontentsofurl:url];  
 3 nsstringencoding enc =    Cfstringconvertencodingtonsstringencoding (kcfstringencodinggb_18030_2000);  
 4 nsstring *retstr = [[NSString alloc] Initwithdata:data ENCODING:ENC];  
 
 Verbose Code 

NSData-NSString
NSString *astring = [[NSString] Alloc] Initwithdata:adata encoding:nsutf8stringencoding];
NSString-NSData
NSString *astring = @ "1234";
NSData *adata = [astring datausingencoding: Nsutf8stringencoding];

2,nsdata and 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];

3,nsdata and UIImage
NSData-UIImage
UIImage *aimage = [UIImage imagewithdata:imagedata];
//Example: Take a picture from a local file sandbox and convert it to 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 and Nsmutabledata
NSData-Msmutabledata
NSData *data=[[nsdata Alloc]init];
Nsmutabledata *mdata=[[nsmutabledata Alloc]init];
Mdata=[nsdata Datawithdata:data];

5,nsdata merged into a nsmutabledata

-(NSString *) Filepathwithname: (NSString *) filename
 {
Nsarray *paths = Nssearchpathfordirectoriesindomains (NSDocumentDirectory, Nsuserdomainmask, YES);
nsstring *documentsdirectory = [Paths objectatindex:0];
return [Documentsdirectory stringbyappendingpathcomponent:filename];
 }
 
-(BOOL) Application: (UIApplication *) application didfinishlaunchingwithoptions: (Nsdictionary *) launchOptions { /c0>
//Audio file path
nsstring *mp3path1 = [[NSBundle mainbundle] pathforresource:@ "1" oftype:@ "MP3"];
nsstring *mp3path2 = [[NSBundle mainbundle] pathforresource:@ "2" oftype:@ "MP3"];
//Audio data
NSData *sound1data = [[NSData alloc] initwithcontentsoffile:mp3path1];
NSData *sound2data = [[NSData alloc] initwithcontentsoffile:mp3path2];
//Merge audio
nsmutabledata *sounds = [Nsmutabledata alloc];
[Sounds appenddata:sound1data];
[Sounds appenddata:sound2data];
//Save audio
 
NSLog (@ "Data length:%d", [sounds length]);
 
[Sounds writetofile:[self filepathwithname:@ "Tmp.mp3"] atomically:yes];
         
[window makekeyandvisible];
     
return YES;
 }

Object-c data type conversion NSData turn Nsstring,byte,uiimage