ios -使用NSLayoutConstraint实现多个view等宽等高等间距

@interface ViewController ()

{

  

    

    UIView *firstView;

    UIView *secondView;

    UIView *thirdView;

    

}

@end



@implementation ViewController



- (void)viewDidLoad

{

    [super viewDidLoad];

    

    /**

      第一个view

     */

    firstView = [[UIView alloc]init];

    firstView.translatesAutoresizingMaskIntoConstraints = NO;

    firstView.backgroundColor = [UIColor blueColor];

    [self.view addSubview:firstView];

    

    /**

     第二个view

     */

    secondView = [[UIView alloc]init];

    secondView.translatesAutoresizingMaskIntoConstraints = NO;

    secondView.backgroundColor = [UIColor brownColor];

    [self.view addSubview:secondView];

    

    /**

     第三个view

     */

    thirdView = [[UIView alloc]init];

    thirdView.translatesAutoresizingMaskIntoConstraints = NO;

    thirdView.backgroundColor = [UIColor yellowColor];

    [self.view addSubview:thirdView];

    

    /**绑定三个view*/

    NSDictionary *dic_bind = NSDictionaryOfVariableBindings(firstView,secondView,thirdView);

    /**设置view之间的间距和高度*/

    NSDictionary *dic_Constraint = @{ @"padding":@(10.f),

                                      @"height":@(150.f)

                                     };

    

    /**

     *  第一个view添加约束

     */

    /**垂直方向居中对齐*/

    NSLayoutConstraint *first_CenterY = [NSLayoutConstraint constraintWithItem:firstView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0];

    

    /**垂直方向添加高度约束*/

    NSArray *first_V = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[firstView(height)]" options:0 metrics:dic_Constraint views:dic_bind];

    [self.view addConstraints:@[first_CenterY]];

    [self.view addConstraints:first_V];

    

    

    /**

     *  第二个view添加约束

     */

    /**垂直方向居中对齐*/

     NSLayoutConstraint *second_CenterY = [NSLayoutConstraint constraintWithItem:secondView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0];

    

     /**垂直方向添加高度约束*/

    NSArray *second_V = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[secondView(height)]" options:0 metrics:dic_Constraint views:dic_bind];

    [self.view addConstraint:second_CenterY];

    [self.view addConstraints:second_V];

    

    /**

     *  第三个view添加约束

     */

    /**垂直方向居中对齐*/

    NSLayoutConstraint *third_CenterY = [NSLayoutConstraint constraintWithItem:thirdView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0];

    

     /**垂直方向添加高度约束*/

    NSArray *third_V = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[thirdView(height)]" options:0 metrics:dic_Constraint views:dic_bind];

    [self.view addConstraints:@[third_CenterY]];

    [self.view addConstraints:third_V];

    

    /**给三个view添加水平约束等宽等间距*/

    NSArray * allConstraint_H = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-padding-[firstView]-10-[secondView(firstView)]-padding-[thirdView(secondView)]-padding-|" options:0 metrics:dic_Constraint views:dic_bind];

    [self.view addConstraints:allConstraint_H];

    

    

}