Question

I want auto filled UITextFiled in my app. In it when user type some letter it will call web service and show response in UIpPickerView like to search city. When we type any letter it shows some city names. Can anyone knows how to do it? Please help me.

Answer 1

To get data from server asynchronously you can use the NSURLConnection and NSURLConnectionDelegate methods

In interface file:

@interface ViewController : UIViewController<NSURLConnectionDelegate, UITextFieldDelegate> {
    NSMutableData *mutableData;
}
-(void)getDataUsingText:(NSString *)text;
@end

In implementation file:

@implementation ViewController
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSString *value =[textField.text stringByReplacingCharactersInRange:range withString:string];
    [self getDataUsingText:value];
    return YES;
}


-(void)getDataUsingText:(NSString *)text;
{
    NSString *urlString = [NSString stringWithFormat:@"http://...."];
    NSURL *url =[NSURL URLWithString:urlString];
    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url];
    NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    [conn start];
}


-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    mutableData = [[NSMutableData alloc] init];
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [mutableData appendData:data];
}


-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{    
    NSString *dataString = [[NSString alloc] initWithData:mutableData encoding:NSUTF8StringEncoding];
    NSLog(@"your data from server: %@", dataString);
    // Here you got the data from server asynchronously.
    // Here you can parse the string and reload the picker view using [picker reloadAllComponents];

}
@end

You must set the delegate to the text field and you have to implement the picker using the data from the NSURLConnectionDelegate method. And this is a tutorial for loading picker view.