IOS Automatic Layout and iOS Layout

IOS Automatic Layout and iOS Layout

The VFL language is used to achieve automatic layout at the beginning. One or two controls are fine, and several more controls are intolerable.

    _backgroundImageView = [[UIImageView alloc] init];    _backgroundImageView.backgroundColor = [UIColor clearColor];    _backgroundImageView.translatesAutoresizingMaskIntoConstraints = NO;    [self addSubview:_backgroundImageView];        NSMutableArray* contraints = [NSMutableArray new];    [contraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[_backgroundImageView]-0-|"                                                                            options:0 metrics:nil                                                                              views:NSDictionaryOfVariableBindings(_backgroundImageView)]];    [contraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[_backgroundImageView]-0-|"                                                                            options:0                                                                            metrics:nil                                                                              views:NSDictionaryOfVariableBindings(_backgroundImageView)]];    [self addConstraints:contraints];

Later, we found that Masonry implements automatic layout like this:

    _scrollView = [[UIScrollView alloc] init];    _scrollView.pagingEnabled = YES;    _scrollView.backgroundColor = [UIColor clearColor];    [self addSubview:_scrollView];    [_scrollView makeConstraints:^(MASConstraintMaker *make) {        make.left.equalTo(0);        make.right.equalTo(0);        make.top.equalTo(0);        make.bottom.equalTo(0);    }];