ios - NSInvalidArgumentException-无法识别的选择器发送到实例？ UITextView/UIPickerView

Question

我试图建立一个文本字段，用用户输入填充pickerView。每次启动应用程序时，我都会收到此错误:

NSInvalidArgumentException', reason: '-[UITextField isEqualToString:]: unrecognized   selector sent to instance.

@synthesize pickerView;
@synthesize textArray;
@synthesize textField;

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.textArray = [[NSMutableArray alloc] init];

    PFUser *currentUser = [PFUser currentUser];
    if (currentUser) {
    NSLog(@"Current user: %@" , currentUser.username);
}
else {
    [self performSegueWithIdentifier:@"showLogin" sender:self];
}
    self.textField.delegate = self;

    self.pickerView.dataSource = self;
    self.pickerView.delegate = self;

NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];

[nc addObserver:self selector:@selector(keyboardWillShow:) name:
 UIKeyboardWillShowNotification object:nil];

[nc addObserver:self selector:@selector(keyboardWillHide:) name:
 UIKeyboardWillHideNotification object:nil];

self.tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                            action:@selector(didTapAnywhere:)];
}

-(void)didTapAnywhere: (UITapGestureRecognizer *) note {
    [self.textField resignFirstResponder];
}
-(void) keyboardWillShow:(NSNotification *) note {
    [self.view addGestureRecognizer:self.tapRecognizer];
}

-(void) keyboardWillHide:(NSNotification *) note
{
    [self.view removeGestureRecognizer:self.tapRecognizer];
}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 1;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:   (NSInteger)component
{
    if ([self.textArray count] == 0)
        return 1;
    return [self.textArray count];
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:   (NSInteger)component {
    return [self.textArray objectAtIndex:row];
}

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row forComponent:    (NSInteger)component{
    NSLog(@"You selected this: %@", [self.textArray objectAtIndex:row]);
}

-(void)textFieldDidEndEditing:(UITextField *)textField{

    [self.textArray addObject:self.textField.text];

    [self.textField resignFirstResponder];

}

- (IBAction)logout:(id)sender {
    [PFUser logOut];
    [self performSegueWithIdentifier:@"showLogin" sender:self];
}
@end

我对所有事物都是新手，因此，如果这很简单，请放轻松吧。干杯!

Answer 1

您必须在收到此错误

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row  forComponent:(NSInteger)component {
    return [self.textArray objectAtIndex:row];
}

当您返回文本字段而不是text(title)时。

在 viewDidLoad中，更改以下行:

[self.textArray addObject:self.textField];

至

[self.textArray addObject:self.textField.text];

确保有一些文本，因此标题不会返回空。那么，您实际上是想放入数组中的什么？是文本还是文本字段？

编辑

首先，我看到的是缺少 文本字段代表。在viewDidLoad中设置 self.textField.delegate = self;，以便调用textFieldDidEndEditing。在其中重新加载pickerview，以便可以使用当前文本正确填充它。

-(void)textFieldDidEndEditing:(UITextField *)textField{

    [self.textArray addObject:self.textField.text];

    [self.pickerView reloadAllComponents];

}

对于选择器标题，当数组中没有数据时，您将返回1。您应该返回注释中所述的内容。

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:   (NSInteger)component {

if(self.textArray.count == 0)
return @"There is nothing";
else
    return [self.textArray objectAtIndex:row];
}

确保关闭键盘，当用户按下“输入键”时，您应该在调用 [self.textfield resignFirstResponder]。用文本框连接一些方法，例如“hidekeyboard”。

-(IBAction) hidekeyboard:(id) sender

{
[sender resignFirstResponder];
}

希望对您有帮助。