php - 阿拉伯语文本存储为“???”

我要做的是将阿拉伯语文本保存在sql中。
我的sql表的排序规则为utf8_general_ci
我在iphone应用程序中有textfield，我正在使用php保存数据。
php代码如下所示。

$con = mysql_connect(localhost, $username, $password);
@mysql_select_db($database) or die("Unable to select database");


$propType = $_POST['propType'];
$price = $_POST['price'];
$type = $_POST['type'];
$zone = $_POST['zone'];
$location = $_POST['location'];
$no_floor = $_POST['no_floor'];
$no_apt = $_POST['no_apt'];
$basement = $_POST['basement'];
$area = $_POST['area'];
$addedBy = $_POST['addedBy'];
$imagePath = $_POST['imagePath'];
$saleType = $_POST['dummy001'];
$mauka = $_POST['mauka'];
$mobileNumForDial = "0";


$result = mysql_query("SELECT mobileNumber FROM userInfo WHERE username='$addedBy'");
while($data = mysql_fetch_row($result)){
    $mobileNumForDial=$data[0];
}

$sql = mysql_query("INSERT INTO buildingData (propType, price, type, zone, location, no_floor,
        no_apt, basement, area, addedBy, imagePath, dummy001, dummy002, mauka)
        VALUES
        ('$propType', '$price', '$type', '$zone', '$location', '$no_floor', '$no_apt', '$basement',
        '$area','$mobileNumForDial','$imagePath', '$saleType', '', '$mauka')");

iPhone代码如下

if ([btnImage.accessibilityIdentifier isEqualToString:@"no_image"]) {
    imageSet = @"missing";
} else {
    imageSet = @"set";
}
post = [[NSString alloc] initWithFormat:@"propType=%d&price=%@&type=%d&zone=%d&location=%d&no_floor=%d&no_apt=%d&basement=%d&area=%@&addedBy=%@&imagePath=%@&dummy001=%d&mauka=%@",
        realEstatePV.selectedItem,
        priceData.text,
        typePV.selectedItem,
        areaPV.selectedItem,
        regionPV.selectedItem,
        floorData.text.intValue,
        aptData.text.intValue,
        basementPV.selectedItem,
        areaData.text,
        [keychainItem objectForKey:kSecAttrAccount],
        imageSet, salePV.selectedItem, mauka.text];
postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

postLength = [NSString stringWithFormat:@"%d", [postData length]];

url = [NSURL URLWithString:@"http://www.smart-kw.com/sama/saveBldgData.php"];

NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url];
[theRequest setHTTPMethod:@"POST"];
[theRequest setValue:postLength forHTTPHeaderField:@"Content-Length"];
[theRequest setHTTPBody:postData];


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

if( theConnection )
{
    indicator.hidden = NO;
    [indicator startAnimating];
    webData = [[NSMutableData data] retain];
}
else
{
    NSLog(@"Internet problem maybe...");
}

问题是
当我储存英文资料时，没问题。
然而，当我输入阿拉伯语文本时，它会被存储为？？？？在mysql数据库中。
知道为什么会这样吗？
编辑1
我也尝试了下面的方法，但是仍然有数据被存储为*？？？

mysql_query("SET NAMES 'utf8'");
mysql_query('SET CHARACTER SET utf8');

$sql = mysql_query("INSERT INTO buildingData (propType, price, type, zone, location, no_floor,
        no_apt, basement, area, addedBy, imagePath, dummy001, dummy002, mauka)
        VALUES
        ('$propType', '$price', '$type', '$zone', '$location', '$no_floor', '$no_apt', '$basement',
        '$area','$mobileNumForDial','$imagePath', '$saleType', '', '$mauka')");

最佳答案

尝试将postdata设置为用utf 8编码而不是ascii编码：

postData = [post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];