无法将NSData转换为图像iphone
我真的不知道为什么它不会将NSData转换为UIImage 。 NSData得到保存，但是当我debugging程序时，想象是用imageData转换时0X0000000000。
这是我的代码：
NSArray *pathArr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *path = [[pathArr objectAtIndex:0] stringByAppendingPathComponent:@"img.data" ]; NSData * imageData = [cerereIndemnizatie.fisier dataUsingEncoding: NSUTF8StringEncoding]; [imageData writeToFile:path atomically:YES]; NSData *retrievedData = [NSData dataWithContentsOfFile:path]; UIImage * imagine = [UIImage alloc] init]; UIImage * imagine = [UIImage imageWithData:retrievedData];
我从networking服务parsing数据的代码。 我打电话writeDataToFileSystem我按下一个button
- (void)viewDidLoad { [super viewDidLoad]; NSURL * url = [NSURL URLWithString:@"http://192.168.1.183:8002/iDocument.asmx"]; NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:15.0]; NSString * parameters = [[NSString alloc] initWithString:[self XmlRequest]]; NSLog(@"Request=%@", parameters); NSString * msgLength = [NSString stringWithFormat:@"%d", [parameters length]]; [request addValue:@"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [request addValue:@"http://tempuri.org/GetDocumenteByIdXML" forHTTPHeaderField:@"SOAPAction"]; [request addValue:msgLength forHTTPHeaderField:@"Content-Length"]; [request setHTTPMethod:@"POST"]; [request setHTTPBody:[parameters dataUsingEncoding:NSUTF8StringEncoding]]; NSURLConnection * connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES]; if (connection){ self.responseData = [NSMutableData data]; } } - (NSString *)XmlRequest { NSString * xml = [[NSString alloc] initWithFormat: @"<?xml version=\"1.0\" encoding=\"utf-8\"?>" "<soap:Envelope xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xsd='http://www.w3.org/2001/XMLSchema' xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'>" "<soap:Body>" "<GetDocumenteByIdXML xmlns='http://tempuri.org/'>" "<user>admin_document</user>" "<password>123</password>" "<id>%@</id>" "</GetDocumenteByIdXML>" "</soap:Body>" "</soap:Envelope>",self.index]; return xml; } - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { NSLog(@"Response: %@", [response textEncodingName]); [self.responseData setLength:0]; } - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { NSLog(@"connection:DidReceiveData"); [self.responseData appendData:data]; } - (void) connectionDidFinishLoading:(NSURLConnection *)connection { NSString * responseString = [[NSString alloc] initWithData:self.responseData encoding:NSUTF8StringEncoding]; NSLog(@"Response string: %@", responseString); self.navigationItem.hidesBackButton = NO; //to do parseXML NSXMLParser * xmlParser = [[NSXMLParser alloc] initWithData:responseData]; xmlParser.delegate = self; BOOL succes = [xmlParser parse]; if (succes) { [self.tableView reloadData]; } else { } } - (void) writeDataToFileSystem { NSArray *pathArr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *path = [[pathArr objectAtIndex:0] stringByAppendingPathComponent:@"img.data" ]; NSData * imageData = [cerereIndemnizatie.fisier dataUsingEncoding: NSUTF8StringEncoding]; [imageData writeToFile:path atomically:YES]; NSData *retrievedData = [NSData dataWithContentsOfFile:path]; //UIImage * imagine = [[UIImage alloc] init]; //UIImage * imagine = [UIImage imageWithData:retrievedData]; UIImage * imagine = [[UIImage alloc] initWithData:retrievedData]; // UIImageView *imgv = [[UIImageView alloc] // initWithFrame:CGRectMake(100, 100, 200, 200)]; // // imgv.image = [UIImage imageWithData:retrievedData]; // [self.view addSubview:imgv]; } - (void) parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict { if (![elementName isEqual:@"DetaliiDocument"]) return; cerereIndemnizatie = [[CerereIndemnizatieDoc alloc] init]; } - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { if ([elementName isEqualToString:@"Id"]) { cerereIndemnizatie.id = currentElementValue; } if ([elementName isEqualToString:@"Nume"]) { cerereIndemnizatie.nume = currentElementValue; } if ([elementName isEqualToString:@"TipDocument"]) { cerereIndemnizatie.tipDocument = currentElementValue; } if ([elementName isEqualToString:@"Fisier"]) { cerereIndemnizatie.fisier = currentElementValue; } else if ([elementName isEqualToString:@"FormatDocument"]) { cerereIndemnizatie.formatDocument = currentElementValue; } currentElementValue = nil; } - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string { if(!currentElementValue) currentElementValue = [[NSMutableString alloc] initWithString:string]; else [currentElementValue appendString:string]; } - (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { NSLog(@"connection:didFailWithError:"); NSLog(@"%@", [error localizedDescription]); }
图像在后端以某种方式编码（例如base64），尝试发现使用哪种编码，并使用相同的algorithm在前端对图像进行解码。 NSUTF8StringEncoding在这种情况下是没有意义的。
imageWithData:不需要一些任意数据，并将其解释为RGBA未压缩纹理。
它需要一个包含识别图像格式（如JPG，PNG或TIFF）的字节的数据，parsing并适当地解压缩图像。