////  ViewController.m//  01-代码实现Autolayout#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        UIView *blueView = [[UIView alloc] init];    blueView.backgroundColor = [UIColor blueColor];    // 不要将AutoresizingMask转为Autolayout的约束    blueView.translatesAutoresizingMaskIntoConstraints = NO;    [self.view addSubview:blueView];        UIView *redView = [[UIView alloc] init];    redView.backgroundColor = [UIColor redColor];    // 不要将AutoresizingMask转为Autolayout的约束    redView.translatesAutoresizingMaskIntoConstraints = NO;    [self.view addSubview:redView];// 添加宽度约束:100        /************************** 蓝色 **************************/    // 添加高度约束:40    NSLayoutConstraint *heightConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:40];    [blueView addConstraint:heightConstraint];        // 添加左边约束：blueView的左边距离父控件左边有20的间距    NSLayoutConstraint *leftConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1.0 constant:20];    [self.view addConstraint:leftConstraint];        // 添加右边约束：blueView的右边距离父控件右边有20的间距    NSLayoutConstraint *rightConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1.0 constant:-20];    [self.view addConstraint:rightConstraint];        // 添加顶部约束：blueView的顶部距离父控件顶部有20的间距    NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0 constant:20];    [self.view addConstraint:topConstraint];        /************************** 红色 **************************/    // 添加高度约束:蓝色等高    NSLayoutConstraint *heightConstraint2 = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeHeight multiplier:1.0 constant:0];    [self.view addConstraint:heightConstraint2];        // 添加左边约束：redView的左边 == 父控件的中心x    NSLayoutConstraint *leftConstraint2 = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0];    [self.view addConstraint:leftConstraint2];        // 添加顶部约束：redView的顶部距离blueView的底部有20的间距    NSLayoutConstraint *topConstraint2 = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeBottom multiplier:1.0 constant:20];    [self.view addConstraint:topConstraint2];        // 添加右边约束：redView的右边 == blueView的右边    NSLayoutConstraint *rightConstraint2 = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeRight multiplier:1.0 constant:0];    [self.view addConstraint:rightConstraint2];}/** * 宽度高度为100，在父控件中垂直水平居中 */- (void)test2{    UIView *blueView = [[UIView alloc] init];    blueView.backgroundColor = [UIColor blueColor];    // 不要将AutoresizingMask转为Autolayout的约束    blueView.translatesAutoresizingMaskIntoConstraints = NO;    [self.view addSubview:blueView];        // 添加宽度约束:父控件的一半    NSLayoutConstraint *widthConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0];    [self.view addConstraint:widthConstraint];        // 添加高度约束:父控件的一半    NSLayoutConstraint *heightConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeHeight multiplier:0.5 constant:0];    [self.view addConstraint:heightConstraint];        // 水平居中    NSLayoutConstraint *centerXConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0];    [self.view addConstraint:centerXConstraint];        // 垂直居中    NSLayoutConstraint *centerYConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0];    [self.view addConstraint:centerYConstraint];}/** * 宽度高度为100，粘着父控件的右上角 */- (void)test1{    UIView *blueView = [[UIView alloc] init];    blueView.backgroundColor = [UIColor blueColor];    // 不要将AutoresizingMask转为Autolayout的约束    blueView.translatesAutoresizingMaskIntoConstraints = NO;    [self.view addSubview:blueView];        // 添加宽度约束:100    NSLayoutConstraint *widthConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:100];    [blueView addConstraint:widthConstraint];        // 添加高度约束:100    NSLayoutConstraint *heightConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:100];    [blueView addConstraint:heightConstraint];        // 添加右边约束：blueView的右边距离父控件右边有10的间距    NSLayoutConstraint *rightConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1.0 constant:-10];    [self.view addConstraint:rightConstraint];        // 添加顶部约束：blueView的顶部距离父控件顶部有10的间距    NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0 constant:10];    [self.view addConstraint:topConstraint];}@end