IOS之AutoLayout

个人感觉，现阶段IOS开发必备技能—–AutoLayout。苹果公司也一直在推荐这个布局方法。现在我们来简单了解一下。直接上代码：

    UIView *backgroundView = [[UIView alloc] init];    [backgroundView setTranslatesAutoresizingMaskIntoConstraints:NO];    backgroundView.backgroundColor = [UIColor blueColor];    [self.view addSubview:backgroundView];    //UILabel    UILabel *textInfoLabel = [[UILabel alloc] init];    [textInfoLabel setTranslatesAutoresizingMaskIntoConstraints:NO];    textInfoLabel.backgroundColor = [UIColor redColor];    textInfoLabel.numberOfLines = 0;    textInfoLabel.font = [UIFont systemFontOfSize:15];    textInfoLabel.text = @"测试";    [self.view addSubview:textInfoLabel];    NSDictionary *views = @{@"backgroundView":backgroundView, @"textInfoLabel":textInfoLabel};    NSDictionary *metrics = @{@"LeftStep":@20, @"TopStep":@30, @"Width":@200, @"Height":@"100", @"VStep":@20, @"HStep":@20};//垂直方向  @“垂直方向:|-距离顶部-[backgroundView(==Width)]-两个view之间的垂直距离-[textInfoLabel(>=一行字的高度)]”    NSString *vLayoutString = @"V:|-TopStep-[backgroundView(==Width)]-VStep-[textInfoLabel(>=20)]";    NSArray *vLayoutArray = [NSLayoutConstraint constraintsWithVisualFormat:vLayoutString options:0 metrics:metrics views:views];    //水平方向       @"水平方向:|-距离左边-[backgroundView(==水平高度（宽度）)-两个view之间的水平距离-[]]    NSString *hLayoutstring = @"H:|-LeftStep-[backgroundView(==Height)]-HStep-[textInfoLabel(==120)]";    NSArray *hLayoutArray = [NSLayoutConstraint constraintsWithVisualFormat:hLayoutstring options:0 metrics:metrics views:views];    [self.view addConstraints:vLayoutArray];    [self.view addConstraints:hLayoutArray];