AUTOVFL (FIT)

1. Adding Constraints (System)

A. A constraint (up or down)

+ (Instancetype) Constraintwithitem: (ID) view1 attribute: (nslayoutattribute) attr1 Relatedby: ( Nslayoutrelation) Relation Toitem: (ID) view2 attribute: (nslayoutattribute) attr2 multiplier: (cgfloat) Multiplier constant: (cgfloat) C;

B. A set of constraints (horizontal, vertical)

+ (Nsarray *) Constraintswithvisualformat: (NSString *) format options: (nslayoutformatoptions) OPTs metrics: ( Nsdictionary *) Metrics Views: (Nsdictionary *) views;

2.VFL Common parameters

function Expression    horizontal direction  H:  vertical Direction  V:    views [view]  Superview (parent view) 　　　　　　　　　　　　|   relationship >=,==,<=   space, Gap -   priority @value

3. Using the VFL

A. View dictionary

Nsdictionary *dict2 = nsdictionaryofvariablebindings (Button,button1);

B. Parameter dictionaries

Nsdictionary *metrics = @{@ "padding": @,@ "height" : @+};

C. Specific use

/**    /*array3 = [Nslayoutconstraint constraintswithvisualformat:@ " h:|-[button1]-| " options:0  metrics:nil views:dict2];     *array4 = [Nslayoutconstraint constraintswithvisualformat:@ "v:[button]-padding-[button1 (==height) ]" options:0  metrics:metrics views:dict2];    [Self.view Addconstraints:array3];    [Self.view Addconstraints:array4];

AUTOVFL (FIT)