【Objective-c】 Masonry的基本使用

Object-C :使用Masonry
Swift:使用Snapkit

Masonry 和 布局优先级约束
呆萌的中指

实例一：

masonary:约束优先级

firstExample.gif

#pragma mark - 基础使用1
- (void)firestExample{
    //红
    [_redView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(self.view.mas_left).with.offset(20);
        make.bottom.mas_equalTo(self.view.mas_bottom).with.offset(-80);
        make.height.equalTo(@50);
    }];
    //蓝
    [_blueView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(_redView.mas_right).with.offset(40);
        make.height.width.bottom.mas_equalTo(_redView);
    }];
    //黄
    [_yellowView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(_blueView.mas_right).with.offset(40);
        make.right.mas_equalTo(self.view.mas_right).with.offset(-20);
        make.height.width.bottom.mas_equalTo(_redView);
        
        //优先级
        //必须添加这个优先级，否则blueView被移除后，redView 和 yellowView 的宽度就不能计算出来
        make.left.mas_equalTo(_redView.mas_right).with.offset(20).priority(250);
    }];
    
    [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(removeBlueView:) userInfo:_blueView repeats:YES];
}

- (void)removeBlueView:(NSTimer *)timer{
    UIView *view = timer.userInfo;
    [view removeFromSuperview];
    [UIView animateWithDuration:0.3 animations:^{
        [self.view layoutIfNeeded];
    }];
}

实例二：

masonry:基本方法

Paste_Image.png

#pragma mark - 基础使用2
- (void)secondExample{
    int padding = 15;
    
    [_redView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(self.view.mas_left).with.offset(padding);
        make.top.mas_equalTo(self.view.mas_top).with.offset(padding);
        make.bottom.mas_equalTo(_yellowView.mas_top).with.offset(-padding);
        make.width.mas_equalTo(_blueView);
    }];

    [_blueView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(_redView.mas_right).with.offset(padding);
        make.right.mas_equalTo(self.view.mas_right).with.offset(-padding);
        make.height.bottom.mas_equalTo(_redView);
    }];

    [_yellowView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(self.view.mas_left).with.offset(padding);
        make.right.mas_equalTo(self.view.mas_right).with.offset(-padding);
        make.bottom.mas_equalTo(self.view.mas_bottom).with.offset(-padding);
        make.height.mas_equalTo(_redView);
    }];
}

实例三：

masonry : 更新约束

ThirdExample.gif

#pragma mark - 点击按钮放大
- (void)growButtonClick{
    self.growButton = [UIButton buttonWithType:UIButtonTypeSystem];
    [self.growButton setTitle:@"点我放大" forState:UIControlStateNormal];
    self.growButton.layer.borderColor = [UIColor greenColor].CGColor;
    self.growButton.layer.borderWidth = 3;
    [self.growButton addTarget:self action:@selector(Click:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.growButton];
    self.scacle = 1.0;
    
    [self.growButton mas_makeConstraints:^(MASConstraintMaker *make) {
        make.center.mas_equalTo(self.view);
        //初始化宽，高，优先级最低
        make.width.height.mas_equalTo(100*self.scacle);
        //最大放大到整个view
        make.width.height.lessThanOrEqualTo(self.view);
    }];
    
}
- (void)Click:(UIButton *)sender{
    self.scacle += 1.0;
    //告诉self.view 约束需要更新
    [self.view setNeedsUpdateConstraints];
    //调用此方法self.view监测是否需要更新约束，若需要则更新，下面添加动画效果才起作用
    [self.view updateConstraintsIfNeeded];
    
    [UIView animateWithDuration:0.3 animations:^{
        [self.view layoutIfNeeded];
    }];
}

//重写该方法来更新约束
- (void)updateViewConstraints{
    //对于已经定义过的约束，需要更改的话，只能是使用update的方法修改才有效
    [self.growButton mas_updateConstraints:^(MASConstraintMaker *make) {
        //这里写需要更新的约束，不用更新的约束将继续存在
        //不会取代，如：其宽高小于屏幕宽高不需要重新再约束
        make.width.height.mas_equalTo(100*self.scacle);
    }];
    [super updateViewConstraints];
}

实例四：

masonry ：重写约束

FourthExample.gif

#pragma mark - 收缩
/*
    注意：multipliedBy必须是对同一个控件本身，如果修改成相对其他控件会导致Crash
 */
- (void)createExpandButton{
    self.isExpanded = NO;
    self.growButton = [UIButton buttonWithType:UIButtonTypeSystem];
    [self.growButton setTitle:@"点我展开" forState:UIControlStateNormal];
    self.growButton.layer.borderColor = [UIColor greenColor].CGColor;
    self.growButton.layer.borderWidth = 3;
    self.growButton.backgroundColor = [UIColor redColor];
    [self.growButton addTarget:self action:@selector(onGrowButtonTaped:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.growButton];
    [self.growButton mas_makeConstraints:^(MASConstraintMaker *make) {
        //mas_equalTo()没有写参考对象的时候，是指父视图
        make.top.left.right.mas_equalTo(0);
        make.bottom.mas_equalTo(-350);
    }];
}
- (void)onGrowButtonTaped:(UIButton *)sender{
    self.isExpanded = !self.isExpanded;
    if (!self.isExpanded) {
        [self.growButton setTitle:@"点我展开" forState:UIControlStateNormal];
    }else{
        [self.growButton setTitle:@"点我收起" forState:UIControlStateNormal];
    }
    [self.view setNeedsUpdateConstraints];
    [self.view updateConstraintsIfNeeded];
    [UIView animateWithDuration:0.3 animations:^{
        [self.view layoutIfNeeded];
    }];
}

- (void)updateViewConstraints{
    //这里使用update也能实现效果
    //remake会将之前的全部移除，然后重新添加
    __weak typeof(self) weakself = self;
    [self.growButton mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.mas_equalTo(0);
        //这里重写全部约束，之前的约束都将无效
        if (weakself.isExpanded) {
            make.bottom.mas_equalTo(0);
        }else{
            make.bottom.mas_equalTo(-350);
        }
    }];
    [super updateViewConstraints];
}

实例五：

masonry ：比例

Paste_Image.png

#pragma mark - 比例
- (void)multipliedBy{
    UIView *topView = [[UIView alloc]init];
    [topView setBackgroundColor:[UIColor redColor]];
    [self.view addSubview:topView];
    
    UIView *topInnerView = [[UIView alloc]init];
    [topInnerView setBackgroundColor:[UIColor greenColor]];
    [topView addSubview:topInnerView];
    
    UIView *bottomView = [[UIView alloc]init];
    [bottomView setBackgroundColor:[UIColor orangeColor]];
    [self.view addSubview:bottomView];
    
    UIView *bottomInnerView = [[UIView alloc]init];
    [bottomInnerView setBackgroundColor:[UIColor blueColor]];
    [bottomView addSubview:bottomInnerView];

    [topView mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.mas_equalTo(0);
        make.height.mas_equalTo(bottomView);
    }];
    
    [topInnerView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.mas_equalTo(0);
        //宽是高的3倍
        make.width.mas_equalTo(topInnerView.mas_height).multipliedBy(3);
        make.center.mas_equalTo(topView);
    }];

    [bottomView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.bottom.right.mas_equalTo(0);
        make.height.mas_equalTo(topView);
        make.top.mas_equalTo(topView.mas_bottom);
    }];

    [bottomInnerView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.bottom.mas_equalTo(bottomView);
        //高是宽的3倍
        make.height.mas_equalTo(bottomInnerView.mas_width).multipliedBy(3);
        make.center.mas_equalTo(bottomView);
    }];
}

完整Demo

================2016 12 26 补充=================
1、约束方法的简写，避免出现错误

//比如第一个例子：
[_redView mas_makeConstraints:^(MASConstraintMaker *make) { 
      make.left.mas_equalTo(self.view.mas_left).with.offset(20); 
      //可以改为：make.left.mas_equalTo(self.view.mas_left).offset(20)
      //虽然只是少了一个with,但是会减少很多bug，因为经常会出现把with打为
      //width,代码又没有报错误，但是运行了就崩溃，就很难找到问题所在了
      make.bottom.mas_equalTo(self.view.mas_bottom).with.offset(-80); 
      make.height.equalTo(@50); 
}];

2、Masonry关于UILabel的约束

宽度自适应：UILabel 的内容宽度是根据内容而定，并且是单行显示，可以设置uilabel 的抗压和抗拉属性
//1、宽度不够时
[_label1 setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
//2、宽度够时
[label setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];

高度自适应：UILabel 的宽度是固定的，高度自适应，只要设置label 的行数就可以了
label.numberOfLines = 0;