• (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;
• (NSArray *)mas_updateConstraints:(void(^)(MASConstraintMaker *make))block;
• (NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block;

// 定義這個(gè)常量，就可以不用在開發(fā)過程中使用"mas_"前綴。
#define MAS_SHORTHAND
// 定義這個(gè)常量，就可以讓Masonry幫我們自動(dòng)把基礎(chǔ)數(shù)據(jù)類型的數(shù)據(jù)，自動(dòng)裝箱為對(duì)象類型。
#define MAS_SHORTHAND_GLOBALS
//  #import "Masonry.h"  這個(gè)頭文件一定要放在上面兩個(gè)宏的后面
mas_makeConstraints 這個(gè)方法只會(huì)添加新的約束
mas_updateConstraints 這個(gè)方法將會(huì)覆蓋以前的某些特定的約束（更新約束）
mas_remakeConstraints 這個(gè)方法會(huì)將以前的所有約束刪掉，添加新的約束
例：
//viewDidLoad
    [_view2 mas_makeConstraints:^(MASConstraintMaker *make) {
        __strong typeof(weakSelf) strongSelf = weakSelf;
        make.center.equalTo(strongSelf.view);
        make.size.mas_equalTo(CGSizeMake(300, 300));
    }];

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [_view2 mas_updateConstraints:^(MASConstraintMaker *make) {
        make.size.mas_equalTo(CGSizeMake(150, 150));
    }];
}

//viewDidLoad
[_view2 mas_makeConstraints:^(MASConstraintMaker *make) {
        __strong typeof(weakSelf) strongSelf = weakSelf;
        make.center.equalTo(strongSelf.view);
        make.size.mas_equalTo(CGSizeMake(300, 300));
 }];
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [_view2 mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.size.mas_equalTo(CGSizeMake(150, 150));
    }];
}
//由于mas_remakeConstraints清除之前的所有約束，所以view2的x，y沒有約束了，出現(xiàn)在（0，0）位置上

設(shè)置約束優(yōu)先級(jí)

    UIView *redView = [[UIView alloc]init];
    redView.backgroundColor = [UIColor redColor];
    [self.view addSubview:redView];
    UIView *greenView = [[UIView alloc]init];
    greenView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:greenView];
    UIView *blueView = [[UIView alloc]init];
    blueView.backgroundColor  = [UIColor blueColor];
    [self.view addSubview:blueView];
//在使用Masonry添加約束之前，需要在addSubview之后才能使用，否則會(huì)導(dǎo)致崩潰。

    [redView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.view.mas_left).offset(20);
        make.bottom.equalTo(self.view.mas_bottom).offset(-20);
        make.width.equalTo(self.view.mas_width).multipliedBy(0.2);
        make.height.equalTo(self.view.mas_height).multipliedBy(0.2);
    }];
    [greenView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(redView.mas_right).offset(20);
        make.bottom.equalTo(self.view.mas_bottom).offset(-20);
        make.width.equalTo(self.view.mas_width).multipliedBy(0.2);
        make.height.equalTo(self.view.mas_height).multipliedBy(0.2);
    }];
    [blueView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(greenView.mas_right).offset(20);
        make.bottom.equalTo(self.view.mas_bottom).offset(-20);
        make.width.equalTo(self.view.mas_width).multipliedBy(0.2);
        make.height.equalTo(self.view.mas_height).multipliedBy(0.2);
        make.left.equalTo(redView.mas_right).offset(20).priority(250);
      //make.left.equalTo(redView.mas_right).offset(20).priorityLow();
//Masonry為我們提供了三個(gè)默認(rèn)的方法，priorityLow()、priorityMedium()、priorityHigh()，這三個(gè)方法內(nèi)部對(duì)應(yīng)著不同的默認(rèn)優(yōu)先級(jí)。
 //除了這三個(gè)方法，我們也可以自己設(shè)置優(yōu)先級(jí)的值，可以通過priority()方法來(lái)設(shè)置。
//優(yōu)先級(jí)的范圍是0~1000，數(shù)字越大，優(yōu)先級(jí)越高，在不設(shè)置的情況下默認(rèn)為1000
//最后添加的這個(gè)約束的優(yōu)先級(jí)是低的，這個(gè)約束只有在它的沖突約束被抹掉后，它才能實(shí)現(xiàn)
    }];


- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self.greenView removeFromSuperview];
    [UIView animateWithDuration:1.0f animations:^{
        [self.view layoutIfNeeded];
    }];
}

大于等于和小于等于某個(gè)值的約束

[self.textLabel mas_makeConstraints:^(MASConstraintMaker *make) {
    make.center.equalTo(self.view);
    // 設(shè)置寬度小于等于200
    make.width.lessThanOrEqualTo(@200);
    // 設(shè)置高度大于等于10
    make.height.greaterThanOrEqualTo(@(10));
}];

設(shè)置約束比例

// 設(shè)置當(dāng)前約束值乘以多少，例如這個(gè)例子是redView的寬度是self.view寬度的0.2倍。
[self.redView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.center.equalTo(self.view);
    make.height.mas_equalTo(30);
    make.width.equalTo(self.view).multipliedBy(0.2);
}];