原生autoLayout 代码实现给 scrollview 添加约束

//
//  ViewController.m
//  原始 autolayout 使用
//
//  Created by hzc on 2017/10/9.
//  Copyright © 2017年 hzc. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, strong) UIScrollView *bgScrollView;
@property (nonatomic, strong) UIView *contentView;
@property (nonatomic, strong) UIView *redView;
@property (nonatomic, strong) UIView *blueView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UIScrollView * bgScrollView  = [[UIScrollView alloc] init];
    bgScrollView.backgroundColor = [UIColor yellowColor];
    bgScrollView.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:bgScrollView];
    _bgScrollView = bgScrollView;
    
    UIView *contentView = [[UIView alloc] init];
    contentView.backgroundColor = [UIColor cyanColor];
    contentView.translatesAutoresizingMaskIntoConstraints = NO;
    [_bgScrollView addSubview:contentView];
    _contentView = contentView;
    
    UIView *view1 = [[UIView alloc] init];
    view1.backgroundColor = [UIColor redColor];
    view1.translatesAutoresizingMaskIntoConstraints = NO;
    [_contentView addSubview:view1];
    _redView = view1;
    
    UIView *view2 = [[UIView alloc] init];
    view2.backgroundColor = [UIColor blueColor];
    view2.translatesAutoresizingMaskIntoConstraints = NO;
    [_contentView addSubview:view2];
    _blueView = view2;
    
    [self setLayout];
    
}

- (void)setLayout {
    // 设置_bgScrollView的约束
    // 上
    NSLayoutConstraint *topCons = [NSLayoutConstraint constraintWithItem:_bgScrollView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1 constant:0];
    // 左
    NSLayoutConstraint *leftCons = [NSLayoutConstraint constraintWithItem:_bgScrollView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1 constant:0];
    // 右
    NSLayoutConstraint *rightCons = [NSLayoutConstraint constraintWithItem:_bgScrollView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1 constant:0];
    // 下
    NSLayoutConstraint *bottomCons = [NSLayoutConstraint constraintWithItem:_bgScrollView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:-60];
    [self.view addConstraints:@[topCons,leftCons,rightCons,bottomCons]];
    
    // 设置 contentView的约束
    // 上
    NSLayoutConstraint *topConsC = [NSLayoutConstraint constraintWithItem:_contentView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:_bgScrollView attribute:NSLayoutAttributeTop multiplier:1 constant:0];
    // 左
    NSLayoutConstraint *leftConsC = [NSLayoutConstraint constraintWithItem:_contentView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:_bgScrollView attribute:NSLayoutAttributeLeading multiplier:1 constant:0];
    // 右
    NSLayoutConstraint *rightConsC = [NSLayoutConstraint constraintWithItem:_contentView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:_bgScrollView attribute:NSLayoutAttributeTrailing multiplier:1 constant:0];
    // 宽 （给 contentView 的宽度一个固定的值）
    NSLayoutConstraint *widthConsC = [NSLayoutConstraint constraintWithItem:_contentView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeWidth multiplier:1 constant:0];
    // 下
    NSLayoutConstraint *bottomConsC = [NSLayoutConstraint constraintWithItem:_contentView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:_bgScrollView attribute:NSLayoutAttributeBottom multiplier:1 constant:0];
    [self.view addConstraints:@[widthConsC]];
    [_bgScrollView addConstraints:@[topConsC,leftConsC,rightConsC,bottomConsC]];
    
    // 设置redView和blueView的约束
    // 上
    NSLayoutConstraint *topConsR = [NSLayoutConstraint constraintWithItem:_redView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeTop multiplier:1 constant:20];
    // 左
    NSLayoutConstraint *leftConsR = [NSLayoutConstraint constraintWithItem:_redView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeLeading multiplier:1 constant:10];
    // 右
    NSLayoutConstraint *rightConsR = [NSLayoutConstraint constraintWithItem:_redView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeTrailing multiplier:1 constant:-10];
    // 下
    NSLayoutConstraint * bottomConsR = [NSLayoutConstraint constraintWithItem:_redView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:_blueView attribute:NSLayoutAttributeTop multiplier:1 constant:-20];
    // 高
    NSLayoutConstraint *heightConsR = [NSLayoutConstraint constraintWithItem:_redView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:200];
    [_redView addConstraints:@[heightConsR]];
    [_contentView addConstraints:@[topConsR,leftConsR,rightConsR,bottomConsR]];
    
    
    // 上   blueView 的上边约束这里可以不用再设置了，因为 redView 的下边约束和这一条约束其实是同一个
//    NSLayoutConstraint *topConsB = [NSLayoutConstraint constraintWithItem:_blueView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:_redView attribute:NSLayoutAttributeBottom multiplier:1 constant:20];
    // 左
    NSLayoutConstraint *leftConsB = [NSLayoutConstraint constraintWithItem:_blueView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeLeading multiplier:1 constant:10];
    // 右
    NSLayoutConstraint *rightConsB = [NSLayoutConstraint constraintWithItem:_blueView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeTrailing multiplier:1 constant:-10];
    // 下
    NSLayoutConstraint * bottomConsB = [NSLayoutConstraint constraintWithItem:_blueView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:_contentView attribute:NSLayoutAttributeBottom multiplier:1 constant:-10];
    // 高
    NSLayoutConstraint *heightConsB = [NSLayoutConstraint constraintWithItem:_blueView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:700];
    [_blueView addConstraints:@[heightConsB]];
    [_contentView addConstraints:@[leftConsB,rightConsB,bottomConsB]];
}


@end

效果图：

1.gif