Masonry初探

Masonry整理

Masonry是以AutoLayout为基础的轻量级布局框架更加简化了整个约束系统

Masonry三方下载
本文参考：
地址1
地址2
地址3
地址4

*Masonry有哪些属性

@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;

(NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;
(NSArray *)mas_updateConstraints:(void(^)(MASConstraintMaker *make))block;
(NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block;
- mas_makeConstraints 只负责添加约束 AutoLayout不能同时存在两条针对同一对象的约束否则会报错
- mas_updateConstraints 针对上面的情况会更新在block中出现的约束不会导致出现两个相同约束的情况
- mas_remakeConstraints 清除之前所有的约束只保留新的约束

**重点：**
**使用mas_makeConstrains方法的元素必须事先添加到父视图中**

* mas_equalTo和equalTo区别：前者比后者多了类型转换操作，支持CGSize CGPoint NSNumber UIEdgeinsets。mas_equalTo是equalTo的封装，equalTo适用于基本数据类型，而mas_equaalTo适用于类似UIEdgeInsetsMake 等复杂类型，基本上它可以替换equalTo。

*  **上左为正 下右为负** 是因为坐标而来的 视图坐标左上为原点 X向右为正 Y向下为正


> 举例比较：
`Make.left.equalTo(@64)` 可以这么写才可以 字面量
`make.left.mas_equalTo(64);` 而mas_equalTo可以不用字面量

1. 先试一下：一个View居中

// 防止block循环引用
__weak typeof (self)weakSelf = self;

UIView *yellow = [UIView new];
yellow.backgroundColor = [UIColor yellowColor];

// 切记添加到父视图中
[self.view addSubview:yellow];
[yellow showPlaceHolder];
/**
* 设置约束
* 使用mas_MakeConstraints:添加约束
*/
[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
// 1.make就是添加约束的控件
// make.left.equalTo 的意思是左侧和谁相同 .offset则是偏移量上左[为正]下右[为负]
make.top.equalTo(self.view.mas_top).offset(30);// 和父视图顶部间距30
make.left.equalTo(self.view.mas_left).offset(30);// 和父视图左边间距30
make.bottom.equalTo(self.view.mas_bottom).offset(-30);// 和父视图底部间距30
make.right.equalTo(self.view.mas_right).offset(-30);// 和父视图右边间距30

    // 2. 2等价于1 edges边缘的意思 
    make.edges.equalTo(self.view).with.insets(UIEdgeInsetsMake(30, 30, 30, 30));
    
    // 3. 还等价于
    make.top.left.bottom.and.right.equalTo(self.view).with.insets(UIEdgeInsetsMake(30, 30, 30, 30));
    
  // 4.此处给yellow一个size 且让其居中

make.size.mas_equalTo(CGSizeMake(300, 300));
make.center.equalTo(self.view);

}];



> size还可以这么写两者也相同

make.size.mas_equalTo(self.view).offset(-20);
make.size.equalTo(self.view).offset(-20);


居中：

make.centerX.equalTo(self.view.mas_centerX);
make.centerY.equalTo(self.view.mas_centerY);

等同于：
`make.center.mas_equalTo(self.view);`

2. 两个view
* 例1



![如图](http://upload-images.jianshu.io/upload_images/982286-a5a9d1f723d51c61.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
![如图](http://upload-images.jianshu.io/upload_images/982286-aaa302bd647dc316.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

[green mas_makeConstraints:^(MASConstraintMaker *make) {
make.size.mas_equalTo(CGSizeMake(200, 120));// green大小
make.top.mas_equalTo(green.superview).offset(100);// green顶部到它父视图的偏移量

    make.bottom.mas_equalTo(yellow.mas_top).offset(-50);// 50如果为正就是green底部到yellow顶部距离为50 为负就是green下边到yellow上边为50
    make.centerX.equalTo(green.superview.mas_centerX);// 中心点的X坐标和父视图中心点的X相同 说人话就是在中间
}];

[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
   
    make.size.mas_equalTo(CGSizeMake(250, 30)); // 给个size
    make.centerX.equalTo(green.mas_centerX);// centerX和green一样


    
}];


`make.size.equalTo(green); `两个view就相同大小 
等同于

make.width.equalTo(green.mas_width);
make.height.equalTo(green.mas_height);

* 例2：

![两个view](http://upload-images.jianshu.io/upload_images/982286-f4a86f6af9a21d16.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

[green mas_makeConstraints:^(MASConstraintMaker *make) {
    // 添加大小约束
    make.size.mas_equalTo(CGSizeMake(100, 100));
    // 添加左上边距约束
    make.left.and.top.mas_equalTo(20);
}];

[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
    // 大小和上边距约束与green相同
    make.size.and.top.equalTo(green);
    // 添加右边距约束 上左为正下右为负
    make.right.mas_equalTo(-20);
}];

**这里的and和with都没有具体操作只是拿来增加程序可读性**
* 例3：
![例3](http://upload-images.jianshu.io/upload_images/982286-3d5fc83d4e4cd910.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

[green mas_makeConstraints:^(MASConstraintMaker *make) {
// 左上约束20 右侧约束-20
make.left.and.top.mas_equalTo(20);
// 右边约束为-20
make.right.mas_equalTo(-20);
}];

[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
    // 下右约束-20
    make.bottom.and.right.mas_equalTo(-20);
    // 高度和green相同
    make.height.equalTo(green);
    // 顶部到green底部距离为20
    make.top.equalTo(green.mas_bottom).offset(20);
    // 左侧到视图中心的距离为20
    make.left.equalTo(weakSelf.view.mas_centerX).offset(20);
}];


` make.right.equalTo(weakSelf.view).offset(-20);`
**等同于**
`make.right.mas_equalTo(-20);`

* 例4:

![屏幕快照 2015-12-07 上午9.42.41.png](http://upload-images.jianshu.io/upload_images/982286-504a0c4c8ec2fbb6.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

UIView *gray = [UIView new];
gray.backgroundColor = [UIColor grayColor];
[self.view addSubview:gray];
[gray showPlaceHolder];

[gray mas_makeConstraints:^(MASConstraintMaker *make) {
    // 左上下距离父视图都为0
    make.left.and.top.and.bottom.mas_equalTo(0);
    // 宽度为200
    make.width.mas_equalTo(200);
}];
UIView *w = [UIView new];
w.backgroundColor = [UIColor colorWithWhite:0.228 alpha:1.000];
[w showPlaceHolder];
[self.view addSubview:w];

UIView *light = [UIView new];
light.backgroundColor = [UIColor lightGrayColor];
[light showPlaceHolder];
[self.view  addSubview:light];

[w mas_makeConstraints:^(MASConstraintMaker *make) {
    // w底部距离父视图centerY的距离为10
    make.bottom.equalTo(weakSelf.view.mas_centerY).mas_equalTo(-10);
    // 左侧距离gray距离为20
    make.left.equalTo(gray).offset(20);
    // 右侧距离gray距离20
    make.right.equalTo(gray).offset(-20);
    make.height.mas_equalTo(100);
}];
[light mas_makeConstraints:^(MASConstraintMaker *make) {
    // 顶部距离父视图centerY为10
    make.top.equalTo(weakSelf.view.mas_centerY).mas_equalTo(10);
    // 左右和高度与w相同
    make.left.and.right.and.height.equalTo(w);

}];

**上下左右边距**

` make.top.left.bottom.right.equalTo(weakSelf.view).with.insets(UIEdgeInsetsMake(20, 20, 100, 20));`
等价
`make.edges.equalTo(weakSelf.view).with.insets(UIEdgeInsetsMake(20, 20, 100, 20));`

* 例5：
![屏幕快照 2015-12-07 下午3.04.56.png](http://upload-images.jianshu.io/upload_images/982286-84d768961ce98cbf.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

 [green mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(weakSelf.view.mas_centerY);
    make.left.equalTo(weakSelf.view.mas_left).offset(10);
    make.right.equalTo(yellow.mas_left).offset(-10);
    make.height.mas_equalTo(150);
    make.width.equalTo(yellow);
}];
[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(weakSelf.view.mas_centerY);
    make.left.equalTo(green.mas_right).offset(10);
    make.right.equalTo(weakSelf.view.mas_right).offset(-10);
    make.height.mas_equalTo(@150);
    make.width.equalTo(green);
}];

* 例6：

![竖屏](http://upload-images.jianshu.io/upload_images/982286-c13ffecf90e7e4ea.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

![横屏](http://upload-images.jianshu.io/upload_images/982286-9708f83548e23c2d.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

[yellow mas_makeConstraints:^(MASConstraintMaker *make) {
    //make.edges.equalTo(self.view).with.insets(UIEdgeInsetsMake(30, 10, 300, 10));
    make.top.left.equalTo(@20);
    make.right.mas_equalTo(-10);
    
}];

[w mas_makeConstraints:^(MASConstraintMaker *make) {
    make.left.mas_equalTo(20);
    make.bottom.mas_equalTo(weakSelf.view).offset(-20);
    make.height.mas_equalTo(yellow);
    make.top.mas_equalTo(yellow.mas_bottom).offset(20);
    make.width.mas_equalTo(green);
    make.right.mas_equalTo(green.mas_left).offset(-20);

}];

[green mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.mas_equalTo(yellow.mas_bottom).offset(20);
    make.left.equalTo(w.mas_right).offset(20);
    make.right.equalTo(yellow.mas_right);
    make.height.mas_equalTo(or.mas_height);
}];

[or mas_makeConstraints:^(MASConstraintMaker *make) {
    
    make.top.mas_equalTo(yellow.mas_top).offset(20);
    make.left.mas_equalTo(yellow.mas_left).offset(30);
    make.width.mas_equalTo(bl.mas_width);
    
}];

[cy mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.mas_equalTo(or.mas_bottom).offset(30);
    make.left.mas_equalTo(or.mas_left);
    make.height.mas_equalTo(or.mas_height);
    make.width.mas_equalTo(or.mas_width);
    make.bottom.mas_equalTo(yellow).offset(-20);
    
}];

[bl mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.mas_equalTo(or.mas_top);
    make.left.mas_equalTo(or.mas_right).offset(20);
    make.bottom.mas_equalTo(cy.mas_bottom);
    make.right.mas_equalTo(weakSelf.view.mas_right).offset(-20);
    
}];


* ScrollView

![屏幕快照 2015-12-07 下午7.33.20.png](http://upload-images.jianshu.io/upload_images/982286-30cdc629a438604e.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

UIScrollView *scr = [UIScrollView new];
scr.backgroundColor = [UIColor whiteColor];
[self.view addSubview:scr];
[scr mas_makeConstraints:^(MASConstraintMaker *make) {
make.edges.equalTo(self.view).with.insets(UIEdgeInsetsMake(10, 10, 10, 10));
}];

UIView *container = [UIView new];
[scr addSubview:container];
[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(scr);
    make.width.equalTo(scr);
}];

int count = 20;
UIView *lastView = nil;

for (int i = 0; i <= count; i++) {
    UIView *subView = [UIView new];
    [container addSubview:subView];
    subView.backgroundColor = [UIColor colorWithHue:( arc4random() % 256 / 256.0 )saturation:( arc4random() % 128 / 256.0 ) + 0.5 brightness:( arc4random() % 128 / 256.0 ) + 0.5 alpha:1];
    [subView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.and.right.equalTo(container);
        make.height.mas_equalTo(@(20 * i));
        if (lastView) {
           // lastView存在时 以其底部为下一个view的顶部
            make.top.mas_equalTo(lastView.mas_bottom);
        } else {
            // lastView不存在时 以父视图的顶部为基准
            make.top.mas_equalTo(container.mas_top);
        }
    }];
    lastView = subView;
}

[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.bottom.equalTo(lastView.mas_bottom);
}];



#####键盘监听
如图：

![屏幕快照 2015-12-07 下午8.55.10.png](http://upload-images.jianshu.io/upload_images/982286-69670567377619c2.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)


![屏幕快照 2015-12-07 下午8.55.22.png](http://upload-images.jianshu.io/upload_images/982286-83f374bb313be9ef.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

`mas_updateConstraints` 利用它来更新约束
初始时约束：

[_textField mas_makeConstraints:^(MASConstraintMaker *make) {
make.size.mas_equalTo(CGSizeMake(200, 30));
make.bottom.mas_equalTo(-40);
make.centerX.equalTo(weakSelf.view.mas_centerX);
}];


键盘弹出在消息方法里更新约束：

-(void)keyBoardWillShow:(NSNotification*)noti {
// 获取键盘基本信息（动画时长与键盘高度）
NSDictionary *userInfo = [noti userInfo];
CGRect rect =
[userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue];

CGFloat keyboardHeight = CGRectGetHeight(rect);
CGFloat keyboardDuration =
[userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

// 修改下边距约束
[_textField mas_updateConstraints:^(MASConstraintMaker *make) {
    make.bottom.mas_equalTo(-keyboardHeight);
}];

// 更新约束

[UIView animateWithDuration:keyboardDuration animations:^{
    [self.view layoutIfNeeded];
}];

}

键盘收起时在textField代理方法中再次更新约束

-(void)keyboardWillDisappear:(NSNotification *)noti {
// 获取键盘基本信息（动画时长与键盘高度）
NSDictionary *userInfo = [noti userInfo];
CGRect rect =
[userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue];

// CGFloat keyboardHeight = CGRectGetHeight(rect);
CGFloat keyboardDuration =[userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

[_textField mas_updateConstraints:^(MASConstraintMaker *make) {
    make.bottom.mas_equalTo(-40);
}];
[UIView animateWithDuration:keyboardDuration animations:^{
    [self.view layoutIfNeeded];
}];

}

Masonry初探

Masonry整理

Masonry是以AutoLayout为基础的轻量级布局框架更加简化了整个约束系统

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