Autolayout / masonry中心有多个视图

Question

I use Masonry to create autolayout constraints in code.

This is what I have so far:

Using the following code:

- (void)viewDidLoad {
    [super viewDidLoad];

    [self.view setBackgroundColor:[UIColor whiteColor]];

    UIView *container = [[UIView alloc] init];
    [self.view addSubview:container];

    UIView *itemContainer = [[UIView alloc] init];
    [itemContainer setBackgroundColor:[UIColor colorWithWhite:0.9 alpha:1.0]];
    [container addSubview:itemContainer];

    UIImageView *itemImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Test"]];
    [itemContainer addSubview:itemImage];

    UILabel *itemTitle = [[UILabel alloc] init];
    [itemTitle setNumberOfLines:1];
    [itemTitle setText:@"Lorem ipsum dolor sit amet."];
    [itemTitle setFont:[UIFont boldSystemFontOfSize:12]];
    [itemTitle setTextColor:[UIColor blackColor]];
    [itemContainer addSubview:itemTitle];

    UILabel *itemText = [[UILabel alloc] init];
    [itemText setNumberOfLines:2];
    [itemText setText:@"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt"];
    [itemText setTextColor:[UIColor blackColor]];
    [itemText setFont:[UIFont systemFontOfSize:10]];
    [itemContainer addSubview:itemText];

    [container makeConstraints:^(MASConstraintMaker *make) {
        UIView *topLayoutGuide = (id)self.topLayoutGuide;
        make.top.equalTo(topLayoutGuide.bottom);
        make.left.right.bottom.equalTo(self.view).insets(UIEdgeInsetsMake(10, 10, 10, 10));
    }];

    [itemContainer makeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.equalTo(container);
        make.height.equalTo(@80);
    }];

    [itemImage makeConstraints:^(MASConstraintMaker *make) {
        make.top.bottom.left.equalTo(itemContainer);
        make.width.equalTo(itemImage.height);
    }];

    [itemTitle makeConstraints:^(MASConstraintMaker *make) {
        make.top.right.equalTo(itemContainer);
        make.left.equalTo(itemImage.right).offset(5);
    }];

    [itemText makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.equalTo(itemTitle);
        make.top.equalTo(itemTitle.bottom).offset(5);
    }];
}

Now I want to center the labels vertically, like so:

My approaches so far have failed. Any idea how to achieve this with autolayout / Masonry?

-- EDIT

Using spacer views like chris838 suggested is working. This is the updated code:

- (void)viewDidLoad {
    [super viewDidLoad];

    [self.view setBackgroundColor:[UIColor whiteColor]];

    UIView *container = [[UIView alloc] init];
    [self.view addSubview:container];

    UIView *itemContainer = [[UIView alloc] init];
    [itemContainer setBackgroundColor:[UIColor colorWithWhite:0.9 alpha:1.0]];
    [container addSubview:itemContainer];

    UIImageView *itemImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Test"]];
    [itemContainer addSubview:itemImage];

    UIView *spacer1 = [[UIView alloc] init];
    [itemContainer addSubview:spacer1];

    UIView *spacer2 = [[UIView alloc] init];
    [itemContainer addSubview:spacer2];

    UILabel *itemTitle = [[UILabel alloc] init];
    [itemTitle setNumberOfLines:1];
    [itemTitle setText:@"Lorem ipsum dolor sit amet."];
    [itemTitle setFont:[UIFont boldSystemFontOfSize:12]];
    [itemTitle setTextColor:[UIColor blackColor]];
    [itemContainer addSubview:itemTitle];

    UILabel *itemText = [[UILabel alloc] init];
    [itemText setNumberOfLines:2];
    [itemText setText:@"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt"];
    [itemText setTextColor:[UIColor blackColor]];
    [itemText setFont:[UIFont systemFontOfSize:10]];
    [itemContainer addSubview:itemText];

    [container makeConstraints:^(MASConstraintMaker *make) {
        UIView *topLayoutGuide = (id)self.topLayoutGuide;
        make.top.equalTo(topLayoutGuide.bottom);
        make.left.right.bottom.equalTo(self.view).insets(UIEdgeInsetsMake(10, 10, 10, 10));
    }];

    [itemContainer makeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.equalTo(container);
        make.height.equalTo(@80);
    }];

    [itemImage makeConstraints:^(MASConstraintMaker *make) {
        make.top.bottom.left.equalTo(itemContainer);
        make.width.equalTo(itemImage.height);
    }];

    [spacer1 makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(itemContainer.top);
        make.height.equalTo(spacer2);
    }];

    [itemTitle makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(spacer1.bottom);
        make.right.equalTo(itemContainer);
        make.left.equalTo(itemImage.right).offset(5);
    }];

    [itemText makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.equalTo(itemTitle);
        make.top.equalTo(itemTitle.bottom).offset(5);
        make.bottom.equalTo(spacer2.top);
    }];

    [spacer2 makeConstraints:^(MASConstraintMaker *make) {
        make.bottom.equalTo(itemContainer.bottom);
        make.height.equalTo(spacer1);
    }];
}

Answer 1

Often when using auto-layout, I find I have to add additional 'spacer' views to achieve the layout I want. See the red coloured views in the example below:

Once you have the layout you want, you can set the views to hidden. Typically the constraints you would need for your spacer view (in this case) would be:

• Top and bottom space to the adjacent view (or superview) set to zero.
• Equal heights.
• Fixed width.
• Centred horizontally in container.

The equal heights bit is obviously the key to getting the content centred!