参考资料https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/AutolayoutPG/VisualFormatLanguage/VisualFormatLanguage.html#//apple_ref/doc/uid/TP40010853-CH3https://developer.apple.com/library/ios/technotes/tn2154/_index.htmlhttps://developer.apple.com/library/mac/documentation/AppKit/Reference/NSLayoutConstraint_Class/NSLayoutConstraint/NSLayoutConstraint.html开源项目Masonry旨在让自动布局（Auto Layout）的代码更简洁、可读性更强，下面是它的地址，个人认为在开发过程中使用Masonry可以是代码更加友好https://github.com/cloudkite/Masonry
- (void)viewDidLoad
{
[super viewDidLoad]; [self addNavigationBar:FEEDBACK_VIEW_CONTROLLER]; UILabel *note = [[UILabel alloc] init];
[note setText:@"欢迎提出宝贵意见！您留下的每一份心意都将浇灌母婴宝的茁壮成长。"];
[note setLineBreakMode:NSLineBreakByWordWrapping];
note.numberOfLines = 0;
[self.view addSubview:note]; //将自适应向布局约束的转化关掉(根据情况有时需要有时不需要)
[note setTranslatesAutoresizingMaskIntoConstraints:NO]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:note
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:navBar
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:10]]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:note
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:note
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:-10]];
UITextView *tfContent = [[UITextView alloc] init];
[tfContent setTranslatesAutoresizingMaskIntoConstraints:NO];
[tfContent setBackgroundColor:[UIColor whiteColor]];
[tfContent setReturnKeyType:UIReturnKeyDone];
[self.view addSubview:tfContent]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfContent
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:note
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfContent
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfContent
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:-10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfContent
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:100]]; UITextField *tfEmail = [UITextField new];
[tfEmail setTranslatesAutoresizingMaskIntoConstraints:NO];
[tfEmail setBackgroundColor:[UIColor whiteColor]];
[tfEmail setClearButtonMode:UITextFieldViewModeAlways];
[tfEmail setReturnKeyType:UIReturnKeyDone];
[tfEmail setPlaceholder:@"请输入邮箱，以便我们联系你！"];
[self.view addSubview:tfEmail]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfEmail
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:tfContent
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfEmail
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfEmail
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:-10]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:tfEmail
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:35]]; UIButton *btnSubmit = [[UIButton alloc] init];
[btnSubmit setTranslatesAutoresizingMaskIntoConstraints:NO];
[btnSubmit setTitle:STRING_COMMON_SUBMIT forState:UIControlStateNormal];
[btnSubmit setBackgroundImage:[UIImage imageNamed:@"bg_red_orange"] forState:UIControlStateNormal];
[btnSubmit setBackgroundImage:[UIImage imageNamed:@"bg_red"] forState:UIControlStateHighlighted];
[self.view addSubview:btnSubmit]; NSMutableArray *tmpConstraints = [NSMutableArray array]; [tmpConstraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[tfEmail]-10-[btnSubmit(==35)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(tfEmail,btnSubmit)]];
[tmpConstraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[btnSubmit]-10-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(btnSubmit)]];
[self.view addConstraints:tmpConstraints];}
