iOS Masonry 使用小记（MASConstraint、center、centerX、edges、equalTo、greaterThanOrEqualTo）

项目中我们经常使用Masonry布局，现在简单记录下自己常用的几种布局方式

1、center 垂直水平居中

[self.bgView addSubview:self.tagLabel];
    [self.tagLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.center.equalTo(self.bgView);
    }];

2、水平居中 centerY

     垂直居中 centerX

[self.bgView addSubview:self.tagLabel];
    [self.tagLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.bgView);
        make.centerY.equalTo(self.bgView);
    }];

3、设置四周间距（和父控件相等大小就是间距为0）

    A.使用edges设置

    和父控件相等大小

[self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.equalTo(self.contentView);
    }];

   上下10 左右15

UIEdgeInsets

UIKIT_STATIC_INLINE UIEdgeInsets UIEdgeInsetsMake(CGFloat top, CGFloat left, CGFloat bottom, CGFloat right) {
    UIEdgeInsets insets = {top, left, bottom, right};
    return insets;
}

[self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.equalTo(self.contentView).insets(UIEdgeInsetsMake(10, 15, 10, 15));
    }];

   B.使用top、left、bottom、right设置

      和父控件相等大小

[self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.contentView);
        make.right.equalTo(self.contentView);
        make.bottom.equalTo(self.contentView);
        make.top.equalTo(self.contentView);
    }];

[self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.top.bottom.equalTo(self.contentView);
    }];

      上下10 左右15

[self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.contentView).offset(15);
        make.right.equalTo(self.contentView).offset(-15);
        make.bottom.equalTo(self.contentView).offset(-10);
        make.top.equalTo(self.contentView).offset(10);
    }];

备注：

相关API

/**
 *  Provides factory methods for creating MASConstraints.
 *  Constraints are collected until they are ready to be installed
 *
 */
@interface MASConstraintMaker : NSObject

/**
 *    The following properties return a new MASViewConstraint
 *  with the first item set to the makers associated view and the appropriate MASViewAttribute
 */
@property (nonatomic, strong, readonly) MASConstraint *left;
@property (nonatomic, strong, readonly) MASConstraint *top;
@property (nonatomic, strong, readonly) MASConstraint *right;
@property (nonatomic, strong, readonly) MASConstraint *bottom;
@property (nonatomic, strong, readonly) MASConstraint *leading;
@property (nonatomic, strong, readonly) MASConstraint *trailing;
@property (nonatomic, strong, readonly) MASConstraint *width;
@property (nonatomic, strong, readonly) MASConstraint *height;
@property (nonatomic, strong, readonly) MASConstraint *centerX;
@property (nonatomic, strong, readonly) MASConstraint *centerY;
@property (nonatomic, strong, readonly) MASConstraint *baseline;

#if (__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 9000) || (__MAC_OS_X_VERSION_MIN_REQUIRED >= 101100)

@property (nonatomic, strong, readonly) MASConstraint *firstBaseline;
@property (nonatomic, strong, readonly) MASConstraint *lastBaseline;

#endif

#if (__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 9000)

@property (nonatomic, strong, readonly) MASConstraint *leftMargin;
@property (nonatomic, strong, readonly) MASConstraint *rightMargin;
@property (nonatomic, strong, readonly) MASConstraint *topMargin;
@property (nonatomic, strong, readonly) MASConstraint *bottomMargin;
@property (nonatomic, strong, readonly) MASConstraint *leadingMargin;
@property (nonatomic, strong, readonly) MASConstraint *trailingMargin;
@property (nonatomic, strong, readonly) MASConstraint *centerXWithinMargins;
@property (nonatomic, strong, readonly) MASConstraint *centerYWithinMargins;

#endif

/**
 *  Returns a block which creates a new MASCompositeConstraint with the first item set
 *  to the makers associated view and children corresponding to the set bits in the
 *  MASAttribute parameter. Combine multiple attributes via binary-or.
 */
@property (nonatomic, strong, readonly) MASConstraint *(^attributes)(MASAttribute attrs);

/**
 *    Creates a MASCompositeConstraint with type MASCompositeConstraintTypeEdges
 *  which generates the appropriate MASViewConstraint children (top, left, bottom, right)
 *  with the first item set to the makers associated view
 */
@property (nonatomic, strong, readonly) MASConstraint *edges;

/**
 *    Creates a MASCompositeConstraint with type MASCompositeConstraintTypeSize
 *  which generates the appropriate MASViewConstraint children (width, height)
 *  with the first item set to the makers associated view
 */
@property (nonatomic, strong, readonly) MASConstraint *size;

/**
 *    Creates a MASCompositeConstraint with type MASCompositeConstraintTypeCenter
 *  which generates the appropriate MASViewConstraint children (centerX, centerY)
 *  with the first item set to the makers associated view
 */
@property (nonatomic, strong, readonly) MASConstraint *center;

/**
 *  Whether or not to check for an existing constraint instead of adding constraint
 */
@property (nonatomic, assign) BOOL updateExisting;

/**
 *  Whether or not to remove existing constraints prior to installing
 */
@property (nonatomic, assign) BOOL removeExisting;

lessThanOrEqualTo、greaterThanOrEqualTo、equalTo

@interface MASConstraint : NSObject

// Chaining Support

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeTop, NSLayoutAttributeLeft, NSLayoutAttributeBottom, NSLayoutAttributeRight
 */
- (MASConstraint * (^)(MASEdgeInsets insets))insets;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeTop, NSLayoutAttributeLeft, NSLayoutAttributeBottom, NSLayoutAttributeRight
 */
- (MASConstraint * (^)(CGFloat inset))inset;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeWidth, NSLayoutAttributeHeight
 */
- (MASConstraint * (^)(CGSize offset))sizeOffset;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeCenterX, NSLayoutAttributeCenterY
 */
- (MASConstraint * (^)(CGPoint offset))centerOffset;

/**
 *    Modifies the NSLayoutConstraint constant
 */
- (MASConstraint * (^)(CGFloat offset))offset;

/**
 *  Modifies the NSLayoutConstraint constant based on a value type
 */
- (MASConstraint * (^)(NSValue *value))valueOffset;

/**
 *    Sets the NSLayoutConstraint multiplier property
 */
- (MASConstraint * (^)(CGFloat multiplier))multipliedBy;

/**
 *    Sets the NSLayoutConstraint multiplier to 1.0/dividedBy
 */
- (MASConstraint * (^)(CGFloat divider))dividedBy;

/**
 *    Sets the NSLayoutConstraint priority to a float or MASLayoutPriority
 */
- (MASConstraint * (^)(MASLayoutPriority priority))priority;

/**
 *    Sets the NSLayoutConstraint priority to MASLayoutPriorityLow
 */
- (MASConstraint * (^)(void))priorityLow;

/**
 *    Sets the NSLayoutConstraint priority to MASLayoutPriorityMedium
 */
- (MASConstraint * (^)(void))priorityMedium;

/**
 *    Sets the NSLayoutConstraint priority to MASLayoutPriorityHigh
 */
- (MASConstraint * (^)(void))priorityHigh;

/**
 *    Sets the constraint relation to NSLayoutRelationEqual
 *  returns a block which accepts one of the following:
 *    MASViewAttribute, UIView, NSValue, NSArray
 *  see readme for more details.
 */
- (MASConstraint * (^)(id attr))equalTo;

/**
 *    Sets the constraint relation to NSLayoutRelationGreaterThanOrEqual
 *  returns a block which accepts one of the following:
 *    MASViewAttribute, UIView, NSValue, NSArray
 *  see readme for more details.
 */
- (MASConstraint * (^)(id attr))greaterThanOrEqualTo;

/**
 *    Sets the constraint relation to NSLayoutRelationLessThanOrEqual
 *  returns a block which accepts one of the following:
 *    MASViewAttribute, UIView, NSValue, NSArray
 *  see readme for more details.
 */
- (MASConstraint * (^)(id attr))lessThanOrEqualTo;

/**
 *    Optional semantic property which has no effect but improves the readability of constraint
 */
- (MASConstraint *)with;

/**
 *    Optional semantic property which has no effect but improves the readability of constraint
 */
- (MASConstraint *)and;

/**
 *    Creates a new MASCompositeConstraint with the called attribute and reciever
 */
- (MASConstraint *)left;
- (MASConstraint *)top;
- (MASConstraint *)right;
- (MASConstraint *)bottom;
- (MASConstraint *)leading;
- (MASConstraint *)trailing;
- (MASConstraint *)width;
- (MASConstraint *)height;
- (MASConstraint *)centerX;
- (MASConstraint *)centerY;
- (MASConstraint *)baseline;

#if (__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 9000) || (__MAC_OS_X_VERSION_MIN_REQUIRED >= 101100)

- (MASConstraint *)firstBaseline;
- (MASConstraint *)lastBaseline;

#endif

#if (__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 9000)

- (MASConstraint *)leftMargin;
- (MASConstraint *)rightMargin;
- (MASConstraint *)topMargin;
- (MASConstraint *)bottomMargin;
- (MASConstraint *)leadingMargin;
- (MASConstraint *)trailingMargin;
- (MASConstraint *)centerXWithinMargins;
- (MASConstraint *)centerYWithinMargins;

#endif


/**
 *    Sets the constraint debug name
 */
- (MASConstraint * (^)(id key))key;

// NSLayoutConstraint constant Setters
// for use outside of mas_updateConstraints/mas_makeConstraints blocks

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeTop, NSLayoutAttributeLeft, NSLayoutAttributeBottom, NSLayoutAttributeRight
 */
- (void)setInsets:(MASEdgeInsets)insets;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeTop, NSLayoutAttributeLeft, NSLayoutAttributeBottom, NSLayoutAttributeRight
 */
- (void)setInset:(CGFloat)inset;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeWidth, NSLayoutAttributeHeight
 */
- (void)setSizeOffset:(CGSize)sizeOffset;

/**
 *    Modifies the NSLayoutConstraint constant,
 *  only affects MASConstraints in which the first item's NSLayoutAttribute is one of the following
 *  NSLayoutAttributeCenterX, NSLayoutAttributeCenterY
 */
- (void)setCenterOffset:(CGPoint)centerOffset;

/**
 *    Modifies the NSLayoutConstraint constant
 */
- (void)setOffset:(CGFloat)offset;


// NSLayoutConstraint Installation support

#if TARGET_OS_MAC && !(TARGET_OS_IPHONE || TARGET_OS_TV)
/**
 *  Whether or not to go through the animator proxy when modifying the constraint
 */
@property (nonatomic, copy, readonly) MASConstraint *animator;
#endif

/**
 *  Activates an NSLayoutConstraint if it's supported by an OS. 
 *  Invokes install otherwise.
 */
- (void)activate;

/**
 *  Deactivates previously installed/activated NSLayoutConstraint.
 */
- (void)deactivate;

/**
 *    Creates a NSLayoutConstraint and adds it to the appropriate view.
 */
- (void)install;

/**
 *    Removes previously installed NSLayoutConstraint
 */
- (void)uninstall;

@end


/**
 *  Convenience auto-boxing macros for MASConstraint methods.
 *
 *  Defining MAS_SHORTHAND_GLOBALS will turn on auto-boxing for default syntax.
 *  A potential drawback of this is that the unprefixed macros will appear in global scope.
 */
#define mas_equalTo(...)                 equalTo(MASBoxValue((__VA_ARGS__)))
#define mas_greaterThanOrEqualTo(...)    greaterThanOrEqualTo(MASBoxValue((__VA_ARGS__)))
#define mas_lessThanOrEqualTo(...)       lessThanOrEqualTo(MASBoxValue((__VA_ARGS__)))

#define mas_offset(...)                  valueOffset(MASBoxValue((__VA_ARGS__)))


#ifdef MAS_SHORTHAND_GLOBALS

#define equalTo(...)                     mas_equalTo(__VA_ARGS__)
#define greaterThanOrEqualTo(...)        mas_greaterThanOrEqualTo(__VA_ARGS__)
#define lessThanOrEqualTo(...)           mas_lessThanOrEqualTo(__VA_ARGS__)

#define offset(...)                      mas_offset(__VA_ARGS__)

#endif


@interface MASConstraint (AutoboxingSupport)

/**
 *  Aliases to corresponding relation methods (for shorthand macros)
 *  Also needed to aid autocompletion
 */
- (MASConstraint * (^)(id attr))mas_equalTo;
- (MASConstraint * (^)(id attr))mas_greaterThanOrEqualTo;
- (MASConstraint * (^)(id attr))mas_lessThanOrEqualTo;

/**
 *  A dummy method to aid autocompletion
 */
- (MASConstraint * (^)(id offset))mas_offset;

@end