在UITextView上成为FirstResponder无效 [英] becomeFirstResponder on UITextView not working

问题描述

由于某种原因，我无法使文本字段成为第一响应者.

For some reason, I'm having trouble with making a textfield the first responder.

我有两行的UITableView.每行都有一个标签和一个UITextField.这些文本字段被标记为kLoginRowIndex = 0和kPasswordRowIndex =1.您可能已经猜到了，我用它来设置登录名和密码.

I have a UITableView with two rows. Each row has a label and a UITextField. The textfields are tagged kLoginRowIndex = 0 and kPasswordRowIndex = 1. As you might have guessed, I use this for setting login and password.

如果用户在编辑登录文本字段时点击返回按钮，我希望密码文本字段成为焦点.不幸的是，密码文本字段不接受焦点.这是我的代码:

If the user taps on the return button when editing the login textfield, I want the password textfield to get the focus. Unfortunately, the password textfield doesn't accept the focus. Here is my code:

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    NSLog(@"%s:(textField.tag:%d)", __FUNCTION__, textField.tag);
    [textField resignFirstResponder];
    if(textField.tag == kLoginRowIndex) {
        UITableViewCell *cell = [self tableView:self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:kPasswordRowIndex inSection:0]];
        UITextField *nextTextField = (UITextField *)[cell viewWithTag:kPasswordRowIndex];
        NSLog(@"(nextTextField.tag:%d)", nextTextField.tag);
        NSLog(@"canBecomeFirstResponder returned %d", [nextTextField canBecomeFirstResponder]);
        NSLog(@"becomeFirstResponder returned %d", [nextTextField becomeFirstResponder]);
    } else {
        [self validate:textField];
    }
    return NO;
}

这是日志输出:

-[SettingsViewController textFieldShouldReturn:]:(textField.tag:0)
(nextTextField.tag:1)
canBecomeFirstResponder returned 1
becomeFirstResponder returned 0

我尝试过的事情:

• 返回是"而不是否"
• 删除对canBecomeFirstResponder的调用(仅用于调试目的)

任何提示都值得赞赏！

推荐答案

在听完tmadsen的建议后，我发现了错误.错误是这一行:

After playing with the suggestion of tmadsen, I found the error. The mistake is this line:

UITableViewCell *cell = [self tableView:self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:k

它返回一个新的单元格，而不是当前屏幕上的单元格.我将其替换为

It returns a new cell, not the one currently on the screen. I replaced it with

UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:kPasswordRowInde

现在它可以正常工作了.

and now it works as expected.

另一方面，我发现0是tag属性的默认值，因此使用它可能不太聪明.

On a side note, I found out that 0 is the default value for the tag property, so it's probably not so clever to use it.

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