set auto layout programmatically in centre of the view iOS

Question

i am new to iOS using blur effect view for whole screen and want to set the auto layout programatically for textfield in centre of the view and my code is :

UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
[blurEffectView setFrame:self.view.bounds];
[self.view addSubview:blurEffectView];

// Vibrancy effect
UIVibrancyEffect *vibrancyEffect = [UIVibrancyEffect effectForBlurEffect:blurEffect];
UIVisualEffectView *vibrancyEffectView = [[UIVisualEffectView alloc] initWithEffect:vibrancyEffect];
[vibrancyEffectView setFrame:self.view.bounds];

UITextField *EmailTextField = [[UITextField alloc] init;
vibrancyEffectView.translatesAutoresizingMaskIntoConstraints = NO;
NSArray *heightConstraint = [NSLayoutConstraint      constraintsWithVisualFormat:@"V:[EmailTextField(30)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(EmailTextField)];
NSArray *widthConstraint = [NSLayoutConstraint constraintsWithVisualFormat:@"H:[EmailTextField(240)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(EmailTextField)];
NSArray *xConstraint = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-42-[EmailTextField(240)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(EmailTextField)];
NSArray *yConstraint = [NSLayoutConstraint constraintsWithVisualFormat:@"V:-150-[EmailTextField(30)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(EmailTextField)];
EmailTextField.textColor = [UIColor redColor];
EmailTextField.font = [UIFont fontWithName:@"Helvetica" size:16];
EmailTextField.backgroundColor=[UIColor clearColor];
EmailTextField.borderStyle = UITextBorderStyleRoundedRect;
[EmailTextField.layer setCornerRadius:10.0f];
EmailTextField.layer.borderWidth = 1.0;
EmailTextField.layer.borderColor = [UIColor whiteColor].CGColor;
EmailTextField.placeholder=@"Email ID";
EmailTextField.textAlignment= NSTextAlignmentCenter;
[[vibrancyEffectView contentView] addSubview:EmailTextField];
[[blurEffectView contentView] addSubview:vibrancyEffectView];
[vibrancyEffectView addConstraints:widthConstraint];
[vibrancyEffectView addConstraints:heightConstraint];
[vibrancyEffectView addConstraints:xConstraint];
[vibrancyEffectView addConstraints:yConstraint];

but gives error :

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse constraint format: Unable to interpret '|' character, because the related view doesn't have a superview H:|-42-[EmailTextField(240)]

I want two solutions- 1.Please correct the code for the same x=42,y=150 positions of the textfield 2.Texfield in centre of the view.

Thanks in advance if any one could help me with the correct code

Answer 1

EmailTextField.center = CGPointMake( self.view.bounds.size.width / 2, your Y); Use this