Masonry是一个轻量级的自动布局库，采用独特的链式语法进行代码封装，具有高可用性和阅读性等特点， 下面来说一下几个实用的例子！
1. 设置类似下图的布局约束
//设置一组button的约束
- (void)masonryArrayWithButton
{
NSArray *titleArray = @[@"按钮1", @"按钮2", @"按钮3", @"按钮4"];
NSMutableArray *mArray = [NSMutableArray array];
for (NSInteger i = 0; i < titleArray.count; i++) {
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setTitle:titleArray[i] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.layer.borderColor = [UIColor blackColor].CGColor;
button.layer.borderWidth = 2;
[self.view addSubview:button];
[mArray addObject:button];
}
[mArray mas_distributeViewsAlongAxis:MASAxisTypeHorizontal withFixedSpacing:20 leadSpacing:20 tailSpacing:20];
[mArray mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(@100);
make.height.equalTo(@40);
}];
}
2. 不设置宽高，会自动适应
//不设置UILabel宽跟高的值
-(void)masonryLabelHeightLayout
{
//文本控件UILabel、按钮UIButton、图片视图UIImageView等，它们具有自身内容尺寸（Intrinsic Content Size），此类用户控件会根据自身内容尺寸添加布局约束。也就是说，如果开发者没有显式给出其宽度或者高度约束，则其自动添加的自身内容约束将会起作用。因此看似“缺失”约束，实际上并非如此
UILabel *myLabel=[[UILabel alloc]init];
myLabel.backgroundColor=[UIColor redColor];
myLabel.text=@"A测试Label不设高度时它的默认值测试Label不设高度时它的默认值";
myLabel.numberOfLines = 0;
[self.view addSubview:myLabel];
[myLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(150);
make.left.mas_equalTo(20);
make.right.mas_equalTo(-60);
}];
UILabel *mySecondLabel=[[UILabel alloc]init];
mySecondLabel.backgroundColor=[UIColor blueColor];
mySecondLabel.text=@"确认";
[self.view addSubview:mySecondLabel];
[mySecondLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.mas_equalTo(myLabel.mas_right).offset(10);
make.centerY.mas_equalTo(myLabel);
}];
}
3. 适用于 一行多个控件 设定一个为优先级问题
//优先级 及至少的情况
-(void)masonryPriorityLayout
{
UILabel *myLabel=[[UILabel alloc]init];
myLabel.backgroundColor=[UIColor redColor];
myLabel.text=@"B1测试Label不设高度时它的默认值,再增加文字长度时的情况";
myLabel.numberOfLines = 0;
[self.view addSubview:myLabel];
[myLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(200);
make.left.mas_equalTo(20);
//至少至右边有80的空间，优先级设高，如果文字不够长 它会以文字本来的宽度
make.right.mas_lessThanOrEqualTo(-80).with.priorityHigh();
}];
UILabel *mySecondLabel=[[UILabel alloc]init];
mySecondLabel.backgroundColor=[UIColor blueColor];
mySecondLabel.text=@"确认";
[self.view addSubview:mySecondLabel];
[mySecondLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(myLabel);
make.left.mas_equalTo(myLabel.mas_right).offset(10);
}];
}
4. 为滚动视图添加约束
//滚动视图添加约束
-(void)masonryScrollViewLayout
{
UIScrollView *scrollView = [UIScrollView new];
scrollView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:scrollView];
[scrollView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(280);
make.size.mas_equalTo(CGSizeMake(350,200));
make.centerX.mas_equalTo(self.view);
}];
UIView *container = [UIView new];
[scrollView addSubview:container];
[container mas_makeConstraints:^(MASConstraintMaker *make) {
make.edges.equalTo(scrollView);
make.width.equalTo(scrollView);
}];
int count = 15;
UIView *lastView = nil;
for ( int i = 1 ; i <= count ; ++i )
{
UIView *subv = [UIView new];
[container addSubview:subv];
subv.backgroundColor = [UIColor colorWithHue:( arc4random() % 256 / 256.0 )
saturation:( arc4random() % 128 / 256.0 ) + 0.5
brightness:( arc4random() % 128 / 256.0 ) + 0.5
alpha:1];
[subv mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.and.right.equalTo(container);
make.height.mas_equalTo(@(30));
if ( lastView )
{
make.top.mas_equalTo(lastView.mas_bottom);
}
else
{
make.top.mas_equalTo(container.mas_top);
}
}];
lastView = subv;
}
//container这个view起到了一个中间层的作用 能够自动的计算uiscrollView的contentSize 下面这句很关键
[container mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(lastView.mas_bottom);
}];
}
