Question

我需要在单击textField时显示datePicker。这是代码：

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
[self setDate];
    return NO;
}


-(void)setDate{

dateSheet = [[UIActionSheet alloc] initWithTitle:Nil delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles: nil];

[dateSheet setActionSheetStyle:UIActionSheetStyleBlackTranslucent];

CGRect pickerFrame = CGRectMake(0, 44, 0, 0);
UIDatePicker *datePicker = [[UIDatePicker alloc] initWithFrame:pickerFrame];
[datePicker setDatePickerMode:UIDatePickerModeDateAndTime];
NSDate * maxDate = [NSDate dateWithTimeIntervalSinceNow:(3600 * 24 * 14)];
datePicker.maximumDate = maxDate;
datePicker.minimumDate = [NSDate date];
[dateSheet addSubview:datePicker];

UIToolbar * controlToolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, dateSheet.bounds.size.width, 44)];

[controlToolBar setBarStyle:UIBarStyleBlack];
[controlToolBar sizeToFit];

UIBarButtonItem *spacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];

UIBarButtonItem *setButton = [[UIBarButtonItem alloc] initWithTitle:@"Imposta" style:UIBarButtonItemStyleDone target:self action:@selector(dismissDate)];
setButton.tintColor = [UIColor whiteColor];

UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithTitle:@"Annulla" style:UIBarButtonItemStyleDone target:self action:@selector(cancelDate)];
cancelButton.tintColor = [UIColor whiteColor];

[controlToolBar setItems:[NSArray arrayWithObjects:spacer, cancelButton, setButton, nil] animated:NO];

[dateSheet addSubview:controlToolBar];
[dateSheet showInView:self.view];
[dateSheet setBounds:CGRectMake(0, 0, 320, 485)];
}

调用showInView时，控制台中会显示很多错误：

CGContextSetFillColorWithColor：无效的上下文0x0。这是一个严重的错误。该应用程序或其使用的库正在使用无效的上下文，从而导致系统稳定性和可靠性的整体降低。此通知是礼貌的：请解决此问题。在即将到来的更新中，它将成为一个致命的错误。

然后同样的消息： CGContextSetStrokeColorWithColor CGContextSaveGState CGContextSetFlatness CGContextAddPath CGContextDrawPath CGContextRestoreGState

为什么会这样？

Answer 1

运行代码后，我发现问题是由UIActionSheet的nil标题引起的。解决方法修改如下。

dateSheet = [[UIActionSheet alloc] initWithTitle:@"" delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles: nil];

另一个好resource供您参考。

DateSheet showInView上的UIDatePicker错误

1 个答案: