IOS development by converting NSDictionary into JSON string
In general, you may use an NSDictionary classification to convert NSDictionary to JSON, as follows:
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:self options:NSJSONWritingPrettyPrinted error:&error];
if (! jsonData) {
return @"{}";
} else {
return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
However, the data types installed by NSDictionary are mixed, and may be Objective-C objects such as NSDate, NSNumber, and NSValue.[NSJSONSerialization dataWithJSONObject:options:error:]This method cannot parse these objects. If there are these objects, it will cause crash. So we should add a step before calling NSJSONSerialization to process all data into NSString, the code is as follows:
NSError *error = nil;
NSData *jsonData = nil;
if (!self) {
return nil;
}
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[self enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
NSString *keyString = nil;
NSString *valueString = nil;
if ([key isKindOfClass:[NSString class]]) {
keyString = key;
}else{
keyString = [NSString stringWithFormat:@"%@",key];
}
if ([obj isKindOfClass:[NSString class]]) {
valueString = obj;
}else{
valueString = [NSString stringWithFormat:@"%@",obj];
}
[dict setObject:valueString forKey:keyString];
}];
jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&error];
if ([jsonData length] == 0 || error != nil) {
return nil;
}
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
return jsonString;
In this way, NSDictionary will not crash if it is converted to JSON. Similarly, NSArray should do the same.
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