UIDatePicker 不弹出

Question

在我的应用程序中，当用户单击 UITextField 时，应该会弹出 UIDatePicker。但是，它没有弹出。当我运行它时，它只显示“选择日期！”在行动表上，没有别的。

这是我的 ViewController.m 中的代码；

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

-(void)textFieldDidBeginEditing:(UITextField *)textField
 {
 [pd resignFirstResponder]; //the textField that you will set the selected date
datePicker = [[UIDatePicker alloc] init]; //declared uidatepicker component

pickerViewDate = [[UIActionSheet alloc] initWithTitle:@"Select the date!"
                                             delegate:self
                                    cancelButtonTitle:nil
                               destructiveButtonTitle:nil
                                    otherButtonTitles:nil];

datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 210, 320, 216)];
datePicker.datePickerMode = UIDatePickerModeDate; //set your specific mode
datePicker.backgroundColor = [UIColor whiteColor];

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]]; //or another LocaleIdentifier instead of en_US
[dateFormatter setDateFormat:@"dd.MM.yyyy"]; //desired format

[datePicker addTarget:self action:@selector(dateChanged) forControlEvents:UIControlEventValueChanged]; //the function would be fired when user change the date in datePicker

//now preparing the toolbar which will be displayed at the top of the datePicker
pickerToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
pickerToolbar.barStyle=UIBarStyleDefault;
[pickerToolbar sizeToFit];
NSMutableArray *barItems = [[NSMutableArray alloc] init];
//UIBarButtonItem *flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneButtonClicked)]; //barbutton item is "DONE" and doneButtonClicked action will be fired when user clicks the button.
//[barItems addObject:flexSpace]; // set the left of the bar

[pickerToolbar setItems:barItems animated:YES];
[pickerViewDate addSubview:pickerToolbar];
[pickerViewDate addSubview:datePicker];
[pickerViewDate showInView:self.view];
[pickerViewDate setBounds:CGRectMake(0,0,320, 464)]; //you can change the position
}

 -(IBAction)dateChanged{

NSDateFormatter *FormatDate = [[NSDateFormatter alloc] init];
[FormatDate setLocale: [[NSLocale alloc]
                        initWithLocaleIdentifier:@"en_US"]];
[FormatDate setDateFormat:@"dd.MM.yyyy"];
pd.text = [FormatDate stringFromDate:[datePicker date]];
}

-(BOOL)closeDatePicker:(id)sender{
[pickerViewDate dismissWithClickedButtonIndex:0 animated:YES];
[pd resignFirstResponder];
return YES;
}

-(IBAction)doneButtonClicked{
[self closeDatePicker:self];
}

 - (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end

我只需要知道我做错了什么的帮助。

Answer 1

阅读 Xcode 文档中对UIActionSheet 的描述。它说：

UIActionSheet 不是为子类而设计的，也不应该添加 查看其层次结构。

最后一点很重要。您不能将选取器视图添加到操作表，因为您不应该将任何视图添加到操作表。

顺便说一句，UIActionSheet 是在 iOS 8 中，我们即将迁移到 iOS 9，因此从本周开始，它将在 2 个主要版本中被弃用。因此，您不应该使用它进行新的开发。我建议您创建自己的视图控制器并以模态方式呈现它，而不是尝试使用UIActionSheet。

Answer 2

您忘记在-(void)textFieldDidBeginEditing:(UITextField *)textField 末尾显示UIActionSheet：

-(void)textFieldDidBeginEditing:(UITextField *)textField
     {
     [pd resignFirstResponder]; //the textField that you will set the selected date
    datePicker = [[UIDatePicker alloc] init]; //declared uidatepicker component

    pickerViewDate = [[UIActionSheet alloc] initWithTitle:@"Select the date!"
                                                 delegate:self
                                        cancelButtonTitle:nil
                                   destructiveButtonTitle:nil
                                        otherButtonTitles:nil];

    datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 210, 320, 216)];
    datePicker.datePickerMode = UIDatePickerModeDate; //set your specific mode
    datePicker.backgroundColor = [UIColor whiteColor];

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
    [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]]; //or another LocaleIdentifier instead of en_US
    [dateFormatter setDateFormat:@"dd.MM.yyyy"]; //desired format

    [datePicker addTarget:self action:@selector(dateChanged) forControlEvents:UIControlEventValueChanged]; //the function would be fired when user change the date in datePicker

    //now preparing the toolbar which will be displayed at the top of the datePicker
    pickerToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
    pickerToolbar.barStyle=UIBarStyleDefault;
    [pickerToolbar sizeToFit];
    NSMutableArray *barItems = [[NSMutableArray alloc] init];
    //UIBarButtonItem *flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneButtonClicked)]; //barbutton item is "DONE" and doneButtonClicked action will be fired when user clicks the button.
    //[barItems addObject:flexSpace]; // set the left of the bar

    [pickerToolbar setItems:barItems animated:YES];
    [pickerViewDate addSubview:pickerToolbar];
    [pickerViewDate addSubview:datePicker];
    [pickerViewDate showInView:self.view];
    [pickerViewDate setBounds:CGRectMake(0,0,320, 464)]; //you can change the position
    [pickerViewDate showInView:self.view]; // <---- here, maybe you forgot

}