以編程方式使用約束來佈局多個視圖

Question

如何使用objective-c中的約束以編程方式創建UIView的2 x 2網格？

例如，我有四個UIViews，其名稱對應於它們的行/列位置（oneOne，oneTwo，twoOne，twoTwo），如下圖所示。

這是我目前使用的代碼：

-(void)buildGrid { 

    [self.view setTranslatesAutoresizingMaskIntoConstraints:NO]; 

    UIView *oneOne = [UIView new]; 
    [oneOne setBackgroundColor:[UIColor redColor]]; 
    [oneOne setTranslatesAutoresizingMaskIntoConstraints:NO]; 

    UIView *oneTwo = [UIView new]; 
    [oneTwo setBackgroundColor:[UIColor greenColor]]; 
    [oneTwo setTranslatesAutoresizingMaskIntoConstraints:NO]; 

    UIView *twoOne = [UIView new]; 
    [twoOne setBackgroundColor:[UIColor blueColor]]; 
    [twoOne setTranslatesAutoresizingMaskIntoConstraints:NO]; 

    UIView *twoTwo = [UIView new]; 
    [twoTwo setBackgroundColor:[UIColor purpleColor]]; 
    [twoTwo setTranslatesAutoresizingMaskIntoConstraints:NO]; 

    [self.view addSubview:oneOne]; 
    [self.view addSubview:oneTwo]; 
    [self.view addSubview:twoOne]; 
    [self.view addSubview:twoTwo]; 

    NSDictionary *viewsDict = NSDictionaryOfVariableBindings(oneOne, oneTwo, twoOne, twoTwo); 



    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[oneOne]-10-[twoOne]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[oneOne]-10-[twoOne]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[oneTwo]-10-[twoTwo]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 


    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[twoOne]-10-[twoTwo]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 

} 

我跟了幾個教程，但沒有（到目前爲止）已經描述瞭如何創建這樣的「網格」佈局，他們已經簡單得多像UIViews單「列」，但是，當我有進一步的「列」我得到有關無法維持的約束錯誤：

Unable to simultaneously satisfy constraints. 
Probably at least one of the constraints in the following list is one you don't want. 

這段代碼工作正常，如果我使它四個UIViews下來或跨屏幕，但不是如果我使它2×2。我做錯了什麼？

更新

按照接受的答案的約束應該是：你

[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[oneOne]-10-[twoOne(==oneOne)]-10-|" 
                    options:0 
                    metrics:nil 
                    views:viewsDict]]; 

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[oneTwo]-10-[twoTwo(==oneTwo)]-10-|" 
                    options:0 
                    metrics:nil 
                    views:viewsDict]]; 

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[oneOne]-10-[oneTwo(==oneOne)]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 


    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[twoOne]-10-[twoTwo(==twoOne)]-10-|" 
                    options:0 
                    metrics:nil 
                    views:viewsDict]]; 

Answer 1

首先在第二約束錯誤。它應該是：

[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[oneOne]-10-[oneTwo]-10-|" 
                    options:NSLayoutFormatDirectionLeadingToTrailing 
                    metrics:nil 
                    views:viewsDict]]; 

此外，您的佈局仍不包含有關子視圖大小（寬度和高度）的任何信息。您必須添加像這樣的約束（僞代碼）

oneOne.width = oneTwo.width = twoOne.width = twoTwo.width 
oneOne.height = oneTwo.height = twoOne.height = twoTwo.height