什么是VFL語(yǔ)言
VFL全稱是VisualFormatLanguage，翻譯過(guò)來(lái)是“可視化格式語(yǔ)言”
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VFL是蘋果公司為了簡(jiǎn)化Autolayout的編碼而推出的抽象語(yǔ)言
UIView *blueView = [[UIView alloc] init];
blueView.backgroundColor = [UIColor blueColor];
// 不要將AutoresizingMask轉(zhuǎn)為Autolayout的約束blueView.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:blueView];
UIView *redView = [[UIView alloc] init];
redView.backgroundColor = [UIColor redColor];
// 不要將AutoresizingMask轉(zhuǎn)為Autolayout的約束
redView.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:redView];
// 間距
NSNumber *margin = @20;
// 添加水平方向的約束
NSString *vfl = @"H:|-margin-[blueView]-margin-[redView(==blueView)]-margin-|";
NSDictionary *views = NSDictionaryOfVariableBindings(blueView, redView);
NSDictionary *mertrics = NSDictionaryOfVariableBindings(margin);
NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:vfl options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:mertrics views:views];
[self.view addConstraints:constraints];
// 添加豎直方向的間距
NSNumber *height = @40;
NSString *vfl2 = @"V:[blueView(height)]-margin-|";
NSDictionary *mertrics2 = NSDictionaryOfVariableBindings(margin, height);
NSArray *constraints2 = [NSLayoutConstraint constraintsWithVisualFormat:vfl2 options:kNilOptions metrics:mertrics2 views:views];
[self.view addConstraints:constraints2];
- 最終效果：
豎屏效果
橫屏效果
