How to make a UITextField in a table cell become first responder?

If I have a series of table cells, each with a text field, how would I make a specific tex开发者_JAVA百科t field become the first responder?

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// Customize the appearance of table view cells.
    
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        UITextField *textField = [[UitextField alloc] init];
        // ...
        textField.delegate = self;
        textField.tag = indexPath.row;
        [cell addSubView:textField];
    }
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    [textField resignFirstResponder];
    return YES;
}

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Swift 4:To make textfield the first responder in tableview simply add this extension to tableView:

extension UITableView {
    func becomeFirstResponderTextField() {
        outer: for cell in visibleCells {
            for view in cell.contentView.subviews {
                if let textfield = view as? UITextField {
                    textfield.becomeFirstResponder()
                    break outer
                }
            }
        }
    }
}

Then in viewDidAppear() call becomeFirstResponderTextField():

func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    tableView.becomeFirstResponderTextField()
}

Note: I am considered visibleCells to search through

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If you want the text field to become first responder after loading the table view,

NSIndexPath *indexPath = /* Index path of the cell containg the text field */;
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
// Assuming that you have set the text field's "tag" to 100
UITextField *textField = (UITextField *)[cell viewWithTag:100];
// Make it the first responder
[textField becomeFirstResponder];

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// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
    {
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
    if(indexPath.row==1)
    {
        [cell.txtField becomeFirstResponder];
    }
    
    return cell;
}

Above code make selected(becomeFirstResponder) textfield in second UItableView cell.

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The UITextField inherits from UIResponder, which implements the becomeFirstResponder message.