检测NSData是否包含NSString

Question

使用NSData保存来自网页的XML文件。能不能检测NSData中包含<?xml version="1.0"?> ?

NSURL *url = [NSURL URLWithString:link];
NSData *data = [NSData dataWithContentsOfURL:url]; 

Answer 1

将NSData转成字符串再判断是否包含<?xml ...?>

BOOL hasXMLTag=NO;
NSString *findStr=@"<?xml version="1.0"?>";
NSString *xml=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if ([xml hasPrefix:findStr]) {
     hasXMLTag=YES;

     //to do your logic
}