*/ 以下不常用
// 务必记住
// 1.当给某个控件设置约束时候,必须关闭这个控件上autoresing
// 2.当给一个控件添加约束时候,必须保证这个控件在控制器View的层次结构中
- (void)viewDidLoad {
[super viewDidLoad];
UIView *redView = [[UIView alloc] init];
redView.backgroundColor = [UIColor redColor];
[self.view addSubview:redView];
UIView *blueView = [[UIView alloc] init];
blueView.backgroundColor = [UIColor blueColor];
[self.view addSubview:blueView];
// Constraint 约束
/*
第一个参数 Item
1.需要约束控件
第二个参数 约束的属性
NSLayoutAttributeLeft = 1, 左边
NSLayoutAttributeRight, 右边
NSLayoutAttributeTop, 顶部
NSLayoutAttributeBottom, 下边
NSLayoutAttributeLeading, 左边
NSLayoutAttributeTrailing, 右边
NSLayoutAttributeWidth, 宽
NSLayoutAttributeHeight, 高
NSLayoutAttributeCenterX, 水平中线
NSLayoutAttributeCenterY, 垂直中线
第三个参数就是 关系
typedef NS_ENUM(NSInteger, NSLayoutRelation) {
NSLayoutRelationLessThanOrEqual = -1, "<="
NSLayoutRelationEqual = 0, "=="
NSLayoutRelationGreaterThanOrEqual = 1, ">="
};
第四个参数 参照物(参照控件)
第五个参数 参照控件的属性
multiplier 乘
constant +
公式
item1.attribute <relation> item2.attribute * multiplier + constant
*/
// 务必记住
// 1.当给某个控件设置约束时候,必须关闭这个控件上autoresing
blueView.translatesAutoresizingMaskIntoConstraints = NO;
redView.translatesAutoresizingMaskIntoConstraints = NO;
// 2.当给一个控件添加约束时候,必须保证这个控件在控制器View的层次结构中
// 添加蓝色的View顶部
NSLayoutConstraint *blueTop = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1 constant:20];
[self.view addConstraint:blueTop];
// 添加蓝色的View左边
NSLayoutConstraint *blueLeft = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:20];
[self.view addConstraint:blueLeft];
// 添加蓝色的View右边
NSLayoutConstraint *blueRight = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-20];
[self.view addConstraint:blueRight];
// 添加蓝色的View的高度
NSLayoutConstraint *blueHeigt = [NSLayoutConstraint constraintWithItem:blueView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:100];
[self.view addConstraint:blueHeigt];
// 添加红色view上面约束
// 红色的顶部
NSLayoutConstraint *redTop = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeBottom multiplier:1 constant:20];
[self.view addConstraint:redTop];
// 红色view与蓝色view右边对齐
NSLayoutConstraint *redRight = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeRight multiplier:1 constant:0];
[self.view addConstraint:redRight];
// 红色view与蓝色view的高度相同
NSLayoutConstraint *redHeight = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeHeight multiplier:1 constant:0];
[self.view addConstraint:redHeight];
// 红色view与蓝色view的高度相同
NSLayoutConstraint *redWidth = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0];
[self.view addConstraint:redWidth];
}
动画
self.vSpaceConstraint.constant += 100;
self.hSpaceContraint.constant += 100;
self.widthcontraint.constant += 100;
self.heightContraint.constant += 100;
[UIView animateWithDuration:1 animations:^{
// 这个方法是让重新布局界面
// 计算约束,然后调节控件的位置
[self.view layoutIfNeeded];
}];
——Vfl 语法
偶尔用
// 一定要关闭autoresizing
- (void)viewDidLoad {
[super viewDidLoad];
// 1.创建子控件,添加加到控制器view中
UIView *blueView = [[UIView alloc] init];
blueView.backgroundColor = [UIColor blueColor];
[self.view addSubview:blueView];
UIView *redView = [[UIView alloc] init];
redView.backgroundColor = [UIColor redColor];
[self.view addSubview:redView];
// 2.关闭autoresizing
blueView.translatesAutoresizingMaskIntoConstraints = NO;
redView.translatesAutoresizingMaskIntoConstraints = NO;
// 3.通过VFL添加约束
// options 对齐方式
// 水平方向
NSArray *hConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[blueView]-20-|" options:NSLayoutFormatAlignAllTop metrics:nil views:@{@"blueView":blueView}];
[self.view addConstraints:hConstraints];
// 竖直方向
NSArray *vConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-20-[blueView(100)]-20-[redView(==blueView)]" options:NSLayoutFormatAlignAllRight metrics:nil views:@{@"blueView":blueView,@"redView":redView}];
[self.view addConstraints:vConstraints];
// VFL 不能参与运算
// NSArray *h1Constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:[redView(==blueView * 0.5)]" options:NSLayoutFormatAlignAllTop metrics:nil views:@{@"blueView":blueView,@"redView":redView}];
//
// [self.view addConstraints:h1Constraints];
NSLayoutConstraint *redW = [NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:blueView attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0];
[self.view addConstraint:redW];
}
