多控件居中

[Wenjie-Qin]

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Issue Info

Info	Value
Platform	e.g. ios/osx/tvos
Platform Version	e.g. 8.0
Masonry Version	e.g. 1.0
Integration Method	e.g. carthage/cocoapods/manually

Issue Description

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[cntrump]

#594

UILayoutGuide *contentLayoutGuide = [[UILayoutGuide alloc] init];
[self.view addLayoutGuide:contentLayoutGuide];
[contentLayoutGuide mas_makeConstraints:^(id<MASLayoutConstraint>  _Nonnull make) {
    make.center.mas_equalTo(0);
    make.width.mas_equalTo(self.view);
}];

NSArray<UIColor *> *colors = @[
    UIColor.redColor,
    UIColor.yellowColor,
    UIColor.blueColor,
    UIColor.greenColor
];

UIView *prev = nil;
NSInteger count = 4;

for (NSInteger i = 0; i < count; i++) {
    UIView *v = [[UIView alloc] init];
    v.backgroundColor = colors[i % 4];
    [self.view addSubview:v];
    [v mas_makeConstraints:^(MASConstraintMaker *make) {
        if (i == 0) {
            make.top.mas_equalTo(contentLayoutGuide).offset(24);
        } else {
            make.top.mas_equalTo(prev.mas_bottom).offset(8);
        }

        make.centerX.equalTo(contentLayoutGuide);

        make.height.mas_equalTo(80);
        make.width.mas_equalTo(contentLayoutGuide).offset(-24);

        if (i == count - 1) {
            make.bottom.mas_equalTo(contentLayoutGuide).offset(-24);
        }
    }];

    prev = v;
}