这次来说一下multipliedBy的用法，
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// Create views UIView *topView = [[UIView alloc] init]; topView.backgroundColor = [UIColor redColor]; [self.view addSubview:topView]; UIView *topInnerView = [[UIView alloc] init]; topInnerView.backgroundColor = [UIColor greenColor]; [topView addSubview:topInnerView]; UIView *bottomView = [[UIView alloc] init]; bottomView.backgroundColor = [UIColor blackColor]; [self.view addSubview:bottomView]; UIView *bottomInnerView = [[UIView alloc] init]; bottomInnerView.backgroundColor = [UIColor blueColor]; [bottomView addSubview:bottomInnerView]; [topView mas_makeConstraints:^(MASConstraintMaker *make) { make.left.right.top.mas_equalTo(0); make.height.mas_equalTo(bottomView); }]; // width = height / 3 [topInnerView mas_makeConstraints:^(MASConstraintMaker *make) { make.left.right.mas_equalTo(topView); //这是最关键的代码，使用multipliedBy必须是对同一个控件本身，比如，上面的代码中，我们都是对bottomInnerView.mas_width本身的，如果修改成相对于其它控件，会出问题。 make.width.mas_equalTo(topInnerView.mas_height).multipliedBy(3); make.center.mas_equalTo(topView); // 设置优先级 make.width.height.mas_equalTo(topView).priorityLow(); make.width.height.lessThanOrEqualTo(topView); }]; [bottomView mas_makeConstraints:^(MASConstraintMaker *make) { make.left.right.bottom.mas_equalTo(0); make.height.mas_equalTo(topView); make.top.mas_equalTo(topView.mas_bottom); }]; // width/height比为1/3.0，要求是同一个控件的属性比例 [bottomInnerView mas_makeConstraints:^(MASConstraintMaker *make) { make.top.bottom.mas_equalTo(bottomView); make.center.mas_equalTo(bottomView); // 注意，这个multipliedBy的使用只能是设置同一个控件的，比如这里的bottomInnerView， // 设置高/宽为3:1 make.height.mas_equalTo(bottomInnerView.mas_width).multipliedBy(3); make.width.height.mas_equalTo(bottomView).priorityLow(); make.width.height.lessThanOrEqualTo(bottomView); }]; |
这里用到这个其实就是设置宽高比，就比如 例子中的 bottomInnerView ，我们想让它的高宽比为3：1，那我们首先设置其top和bottom与父视图一致且始终在父视图中居中显示，然后我们通过make.width.height.lessThanOrEqualTo设置了宽、高的最大值与父视图相同，然后设置了宽和高与父视图相等，但是优先级为最低，以保证子视图的宽高不超过父视图，最后，我们设置了bottomInnerView的高为宽的3倍。 make.height.mas_equalTo(bottomInnerView.mas_width).multipliedBy(3)
代码请查看 http://git.oschina.net/zcb1603999/DCTest
转载请注明：怼码人生 » iOS自动布局之Masonry第五弹
