iOS AutoLayout 編碼

//這個地方不要定義Frame，下面的Visual Format才是定義Frame相關的地方

UIView *redView = [[UIView alloc] init];

redView.backgroundColor = [UIColor redColor];

//參照Apple Doc 這個地方設定NO，是為了不讓Constraint與View本身的autoresize衝突

[redView setTranslatesAutoresizingMaskIntoConstraints:NO];

[self.view addSubview:redView];

UIView *blueView = [[UIView alloc] init];

blueView.backgroundColor = [UIColor blueColor];

[blueView setTranslatesAutoresizingMaskIntoConstraints:NO];

[self.view addSubview:blueView];

//綁定兩個View相關

NSDictionary *views = NSDictionaryOfVariableBindings(redView, blueView);

//此處的constraint是為了定義Frame水平方向相關（x, width）

[self.view addConstraints: [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(>=10)-[redView(200)]"

options:0

metrics:nil

views:views]];

//此處的constraint是為了定義Frame豎直方向相關（y, height）

[self.view addConstraints: [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(>=240)-[redView(100)]"

options:0

metrics:nil

views:views]];

[self.view addConstraints: [NSLayoutConstraint constraintsWithVisualFormat:@"H:[blueView(==redView)]"

options:0

metrics:nil

views:views]];

[self.view addConstraints: [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(40)-[blueView(==redView)]"

options:0

metrics:nil

views:views]];

//此處的constraint是為了描述以上兩個view的關係

[self.view addConstraint: [NSLayoutConstraint constraintWithItem:blueView

attribute:NSLayoutAttributeLeft

relatedBy:NSLayoutRelationEqual

toItem:redView

attribute:NSLayoutAttributeLeft

multiplier:1

constant:0]];

以上.

關於Method和Macro不提供解釋，請參照Apple Doc.