Springboard crash when launching apps - objective-c

Question

I'm trying to make a theos tweak that will blur the background and show a text field of password when user enters any application. The text field that I use is a custom text field class(JVFloatLabeledTextField). The code works just fine without the custom text field but when I add it, the springboard crashes.
Here is the code:
#import "JVFloatLabeledTextField.h"
typedef enum {
SBIconLocationHomeScreen = 0,
SBIconLocationDock = 1,
SBIconLocationSwithcer = 2
} SBIconLocation;
#interface SBApplicationIcon
- (void)launchFromLocation:(SBIconLocation)location context:(id)arg2;
#end
%hook SBApplicationIcon
- (void)launchFromLocation:(SBIconLocation)location context:(id)arg2 {
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
[blurEffectView setFrame:window.bounds];
[UIView transitionWithView:window duration:0.4 options:UIViewAnimationOptionTransitionCrossDissolve animations: ^ {
[window addSubview:blurEffectView];
} completion:nil];
blurEffectView.translatesAutoresizingMaskIntoConstraints = NO;
[window addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[blurEffectView]|" options:NSLayoutFormatAlignAllCenterX metrics:nil views:NSDictionaryOfVariableBindings(blurEffectView)]];
[window addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[blurEffectView]|" options:NSLayoutFormatAlignAllCenterY metrics:nil views:NSDictionaryOfVariableBindings(blurEffectView)]];
JVFloatLabeledTextField *pwt = [[%c(JVFloatLabeledTextField) alloc] initWithFrame:CGRectMake(0, 0, 120, 44)];
pwt.font = [UIFont systemFontOfSize:16.0f];
pwt.attributedPlaceholder = [[NSAttributedString alloc] initWithString:NSLocalizedString(#"Enter your password", #"")
attributes:#{NSForegroundColorAttributeName: [UIColor lightGrayColor]}];
pwt.textColor = [UIColor whiteColor];
pwt.floatingLabelFont = [UIFont boldSystemFontOfSize:11.0f];
pwt.floatingLabelTextColor = [UIColor greenColor];
pwt.tintColor = [UIColor greenColor];
pwt.keyboardType = UIKeyboardTypeNumberPad;
pwt.translatesAutoresizingMaskIntoConstraints = NO;
pwt.clearButtonMode = UITextFieldViewModeWhileEditing;
[UIView transitionWithView:window duration:0.4 options:UIViewAnimationOptionTransitionCrossDissolve animations: ^ {
[window addSubview:pwt];
} completion:nil];
[window addConstraints:[NSLayoutConstraint
constraintsWithVisualFormat:#"V:|-210-[pwt(>=44)]"
options:NSLayoutFormatDirectionLeadingToTrailing
metrics:nil
views:NSDictionaryOfVariableBindings(pwt)]];
[window addConstraints:[NSLayoutConstraint
constraintsWithVisualFormat:#"H:[pwt]"
options:0
metrics:nil
views:NSDictionaryOfVariableBindings(pwt)]];
[window addConstraint:[NSLayoutConstraint
constraintWithItem:pwt attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:window attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0]];
}
%end
Can you tell me what is the problem in the code?
Thanks in advance.