我必須以自動佈局約束編程添加標籤和文本字段，但項目崩潰

Question

這裏是我的代碼。 我有編程加入自動佈局約束，但是項目的崩潰，由於約束沒有正確設定 plz幫助我解決這個錯誤

-(void)autoLayoutProgrametacally 
{ 

UIImageView *imgView = [[UIImageView alloc] init]; 
imgView.contentMode = UIViewContentModeScaleAspectFit; 
imgView.translatesAutoresizingMaskIntoConstraints = NO; 
UIImage *image =[UIImage imageNamed:@"background.jpg"]; 
[imgView setImage:image]; 
[self.view addSubview:imgView]; 

NSArray *imageViewHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[imgView]-0-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]; 
NSArray *imageViewVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[imgView]-0-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]; 

[self.view addConstraints:imageViewHorConst]; 
[self.view addConstraints:imageViewVerConst]; 


UILabel *FirstName = [[UILabel alloc] init]; 
[FirstName setTranslatesAutoresizingMaskIntoConstraints:NO]; 
[FirstName setNumberOfLines:1]; 
[FirstName setText:@"First Name:"]; 
[self.view addSubview:FirstName]; 
UILabel *LastName = [[UILabel alloc] init]; 
[LastName setTranslatesAutoresizingMaskIntoConstraints:NO]; 
[LastName setNumberOfLines:1]; 
[LastName setText:@"Last Name:"]; 
[self.view addSubview:LastName]; 
UITextField *txtFirstName=[[UITextField alloc]init]; 
[txtFirstName setTranslatesAutoresizingMaskIntoConstraints:NO]; 
UITextField *txtLastName=[[UITextField alloc]init]; 
[txtLastName setTranslatesAutoresizingMaskIntoConstraints:NO]; 




NSArray *FirstNameVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(10)-[FirstName]" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:nil views:NSDictionaryOfVariableBindings(FirstName)]; 
NSArray *FirstNameHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(10)-[FirstName(txtFirstName)]-(10)-[txtFirstName]" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:nil views:@{@"FirstName":FirstName, @"txtFirstName":txtFirstName}]; 
NSArray *LastNameVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[LastName]" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:nil views:NSDictionaryOfVariableBindings(LastName)]; 
NSArray *LastNameHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[LastName(txtLastName)]-(10)-[txtLastName]" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:nil views:@{@"LastName":LastName, @"txtLastName":txtLastName}]; 


[self.view addConstraints:FirstNameVerConst]; 
[self.view addConstraints:FirstNameHorConst]; 
[self.view addConstraints:LastNameVerConst]; 
[self.view addConstraints:LastNameHorConst]; 
} 

Answer 1

我已編輯的代碼中添加一行標籤和文本字段...嘗試這可能會幫助... 用這個替換您的代碼...

-(void)autoLayoutProgrametacally 
{ 

UIImageView *imgView = [[UIImageView alloc] init]; 
imgView.contentMode = UIViewContentModeScaleAspectFit; 
imgView.translatesAutoresizingMaskIntoConstraints = NO; 
UIImage *image =[UIImage imageNamed:@"background.jpg"]; 
[imgView setImage:image]; 
[self.view addSubview:imgView]; 

NSArray *imageViewHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[imgView]-0-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]; 
NSArray *imageViewVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[imgView]-0-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]; 

[self.view addConstraints:imageViewHorConst]; 
[self.view addConstraints:imageViewVerConst]; 


UILabel *FirstName = [[UILabel alloc] init]; 
[FirstName setTranslatesAutoresizingMaskIntoConstraints:NO]; 
[FirstName setNumberOfLines:1]; 
[FirstName setText:@"First Name:"]; 
FirstName.textColor=[UIColor whiteColor]; 
[self.view addSubview:FirstName]; 

UITextField *txtFirstName=[[UITextField alloc]init]; 
txtFirstName.placeholder=@"FirstName"; 
txtFirstName.contentMode = UIViewContentModeScaleAspectFit; 
txtFirstName.translatesAutoresizingMaskIntoConstraints = NO; 
txtFirstName.backgroundColor = [UIColor whiteColor]; 
txtFirstName.font = [UIFont systemFontOfSize:10.0]; 
txtFirstName.leftViewMode = UITextFieldViewModeAlways; 
[self.view addSubview:txtFirstName]; 

UILabel *LastName = [[UILabel alloc] init]; 
[LastName setTranslatesAutoresizingMaskIntoConstraints:NO]; 
[LastName setNumberOfLines:1]; 
[LastName setText:@"Last Name:"]; 
LastName.textColor=[UIColor whiteColor]; 
[self.view addSubview:LastName]; 

UITextField *txtLastName=[[UITextField alloc]init]; 
txtLastName.placeholder=@"LastName"; 
txtLastName.contentMode = UIViewContentModeScaleAspectFit; 
txtLastName.translatesAutoresizingMaskIntoConstraints = NO; 
txtLastName.backgroundColor = [UIColor whiteColor]; 
txtLastName.font = [UIFont systemFontOfSize:10.0]; 
txtLastName.leftViewMode = UITextFieldViewModeAlways; 
[self.view addSubview:txtLastName]; 




NSDictionary *metrics = @{@"height":@30.0}; 

NSArray *FirstNameVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(30)-[FirstName(25)]" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:nil views:NSDictionaryOfVariableBindings(FirstName)]; 
NSArray *FirstNameHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-15-[FirstName(txtFirstName)]-10-[txtFirstName(250)]-10-|" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:metrics views:NSDictionaryOfVariableBindings(FirstName,txtFirstName)]; 



NSArray *LastNameVerConst = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[FirstName(LastName)]-[LastName(25)]" options:0 metrics:nil views:@{@"FirstName":FirstName , @"LastName":LastName }]; 


NSArray *LastNameHorConst = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-15-[LastName(txtLastName)]-10-[txtLastName(250)]-10-|" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:metrics views:NSDictionaryOfVariableBindings(LastName,txtLastName)]; 

[self.view addConstraints:FirstNameVerConst]; 
[self.view addConstraints:FirstNameHorConst]; 
[self.view addConstraints:LastNameVerConst]; 
[self.view addConstraints:LastNameHorConst]; 
}