iOS/Objective-C - How do I query a web server data

问题:

I'm not sure how to run a PHP script from Objective-C to retrieve GET data for querying a database. Is there a way to execute and retrieve returned data from a PHP script directly from Objective-C? Better yet, is there functionality to query a MySQL database server directly from iOS/Objective-C? Any thoughts are appreciated.

Jake

回答1:

you can safely query a mysql database, directly from objective-c.

you must create a php code like this:

<?php
$con = mysql_connect("server", "username", "password");
if (!$con)
{
 die('Could not connect: ' . mysql_error());
}

mysql_select_db("username_numberOfTable", $con);

$query = mysql_query("SELECT id, Name, Type FROM table") 
or die ('Query is invalid: ' . mysql_error());

$intNumField = mysql_num_fields($query);
$resultArray = array();

while ($row = mysql_fetch_array($query)) {

$arrCol = array();
for($i=0;$i<$intNumField;$i++)
   {

    $arrCol[mysql_field_name($query,$i)] = $row[$i];

} 

array_push($resultArray,$arrCol);

}

mysql_close($con);

echo json_encode($resultArray);

?>

and this is the part of objective-c:

- (void)viewDidLoad {

  NSString *stringName = @"Name";
  NSString *stringType = @"Type";

    NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL    URLWithString:@"http://yourURL.php?"]];

NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest  delegate:self];
 }

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

[receivedData appendData:data];

 }

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

if (receivedData) {

      id jsonObjects = [NSJSONSerialization JSONObjectWithData:receivedData options:NSJSONReadingMutableContainers error:nil];

    for (NSDictionary *dataDict in jsonObjects) {

        NSString *stringNameID = [dataDict objectForKey:@"Name"];
        NSString *stringTypeID = [dataDict objectForKey:@"Type"];


    dict = [NSDictionary dictionaryWithObjectsAndKeys:stringNameID, stringName, stringTypeID, stringType, nil];

        [yourNSMutableArray addObject:dict];


    }

   [self.tableView reloadData];

 }

}


 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath  {

 NSDictionary *tmpDict = [yourNSMutableArray objectAtIndex:indexPath.row];

cell.textLabel.text = [tmpDict objectForKey:stringName];
cell.detailTextLabel.text = [tmpDict objectForKey:stringType];


 }

and that's it, I hope can I help

回答2:

There are two types of service that can be used to send data to a web server:

1. Synchronous NSURL Request

2. Asynchronous NSURL Request

If you want to only post data to web server then use an asynchronous request because it works in the background and doesn't block the user interface.

NSString *content = @"txtfiedl.text=1";

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://www.ex.com/yourfile.php"]];
[urlRequest setHTTPMethod:@"POST"];
[urlRequest setHTTPBody:[content dataUsingEncoding:NSISOLatin1StringEncoding]];

[NSURLConnection connectionWithRequest:request delegate:self];