这次我们考虑一下子视图跟随父视图变化而变化的做法
/**子随父动的方法**/
- (void)sonViewWithFatherView{
UIView *greenView = [[UIView alloc] init];
greenView.backgroundColor = UIColor.greenColor;
greenView.layer.borderColor = UIColor.blackColor.CGColor;
greenView.layer.borderWidth = 2;
[self.view addSubview:greenView];
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onTap)
];
[greenView addGestureRecognizer:tap];
self.greenView = greenView;
UIView *blueView = UIView.new;
blueView.backgroundColor = UIColor.blueColor;
blueView.layer.borderColor = UIColor.blackColor.CGColor;
blueView.layer.borderWidth = 2;
[self.view addSubview:blueView];
self.blueView = blueView;
// 这里，我们不使用updateViewConstraints方法，但是我们一样可以做到。
// 不过苹果推荐在updateViewConstraints方法中更新或者添加约束的
[self updateWithExpand:NO animated:NO];
UILabel *label = [[UILabel alloc] init];
label.numberOfLines = 0;
label.textColor = [UIColor redColor];
label.font = [UIFont systemFontOfSize:16];
label.textAlignment = NSTextAlignmentCenter;
label.text = @"点击绿色部分放大，蓝色部分最大值250，最小值90";
[self.greenView addSubview:label];
[label mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.mas_equalTo(0);
make.left.right.mas_equalTo(0);
}];
}
- (void)updateWithExpand:(BOOL)isExpanded animated:(BOOL)animated {
self.isExpaned = isExpanded;
[self.greenView mas_updateConstraints:^(MASConstraintMaker *make) {
make.left.top.mas_equalTo(20);
make.right.mas_equalTo(-20);
if (isExpanded) {
make.bottom.mas_equalTo(-20);
} else {
make.bottom.mas_equalTo(-300);
}
}];
[self.blueView mas_updateConstraints:^(MASConstraintMaker *make) {
make.center.mas_equalTo(self.greenView);
// 这里使用优先级处理
// 设置宽高，这里用的连贯操作
if (!isExpanded) {
make.width.height.mas_equalTo(100 * 0.5).priorityLow();
} else {
make.width.height.mas_equalTo(100 * 3).priorityLow();
}
// 最大值为250
make.width.height.lessThanOrEqualTo(@250);
// 最小值为90
make.width.height.greaterThanOrEqualTo(@90);
}];
if (animated) {
[self.view setNeedsUpdateConstraints];
[self.view updateConstraintsIfNeeded];
[UIView animateWithDuration:0.5 animations:^{
[self.view layoutIfNeeded];
}];
}
}
- (void)onTap {
[self updateWithExpand:!self.isExpaned animated:YES];
}
当我们没有点击的时候，两个视图都会变大，这里要注意一下：我们没有使用updateViewConstraints方法，但是我们一样做到了。不过苹果推荐在updateViewConstraints方法中更新或者添加约束的
