Layout--iOS

2019-11-14 17:52:48

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// 系統的約束代碼

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

UIView *superView = self.view;

UIView *viewDemo = [[UIView alloc] init];

viewDemo.translatesAutoresizingMaskIntoConstraints = NO;

viewDemo.backgroundColor = [UIColor orangeColor];

[superView addSubview:viewDemo];

UIEdgeInsets padding = UIEdgeInsetsMake(10, 10, 10, 10);

[superView addConstraints:@[

　　　　　　　　　　　// viewDemo頂部距離父視圖superView頂部距離為padding.top(即為：10)，

[NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeTop multiplier:1 constant:padding.top],

[NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeLeft multiplier:1 constant:padding.left],

[NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeRight multiplier:1 constant:-padding.right],

[NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeBottom multiplier:1 constant:-padding.bottom]

]];

}

// 注：若是把右邊約束去掉，改為如下語句

// [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0]

// 則viewDemo的寬度變為superView的0.5倍?。?/span>

//***************************************************

// VFL語言

　 UIView *viewLeft = [[UIView alloc] init];

viewLeft.translatesAutoresizingMaskIntoConstraints = NO;

viewLeft.backgroundColor = [UIColor orangeColor];

[self.view addSubview:viewLeft];

UIView *viewRight = [[UIView alloc] init];

viewRight.translatesAutoresizingMaskIntoConstraints = NO;

viewRight.backgroundColor = [UIColor redColor];

[self.view addSubview:viewRight];

// horizontal：水平方向距左邊10，距右邊10

//簡單說來，NSDictionaryOfVariableBindings(scrollView)就等于@{@”scrollView”: scrollView}

NSDictionary *constraintDict = NSDictionaryOfVariableBindings(viewLeft,viewRight);

NSArray *hConstraintArrayLeft = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(10)-[viewLeft]-(10)-|" options:0 metrics:nil views:constraintDict];

// vertical：垂直方向距頂部30，控件高度100

NSArray *vConstraintArrayLeft = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(30)-[viewLeft(100)]" options:0 metrics:nil views:constraintDict];

// 添加到父視圖上

[self.view addConstraints:hConstraintArrayLeft];

[self.view addConstraints:vConstraintArrayLeft];

NSArray *hConstraintArrayRight = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(10)-[viewRight]-(10)-|" options:0 metrics:nil views:constraintDict];

// viewRight距viewLeft的垂直距離為50

NSArray *vConstraintArrayRight = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[viewLeft]-(50)-[viewRight(200)]" options:0 metrics:nil views:constraintDict];

[self.view addConstraints:hConstraintArrayRight];

[self.view addConstraints:vConstraintArrayRight];

//***************************************************

// 三方庫：Masonry

// 居中

// 快速定義一個weakSelf，用于block里面，防止循環引用

#define WS(weakSelf) __weak __typeof(&*self)weakSelf = self

WS(ws);

UIView *sv = [UIView new];

sv.backgroundColor = [UIColor orangeColor];

// 在做autoLayout之前一定要先將view添加到superView上否則會報錯

[self.view addSubview:sv];

[sv mas_makeConstraints:^(MASConstraintMaker *make) {

// 居中

make.center.equalTo(ws.view);

// 設置size

make.size.mas_equalTo(CGSizeMake(300, 300));

}];

3. [初級] 讓兩個高度為150的view垂直居中且等寬且等間隔排列間隔為10(自動計算其寬度)

int padding1 = 10;
[sv2 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(sv.mas_centerY);
    make.left.equalTo(sv.mas_left).with.offset(padding1);
    make.right.equalTo(sv3.mas_left).with.offset(-padding1);
    make.height.mas_equalTo(@150);
    make.width.equalTo(sv3);
}];
[sv3 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(sv.mas_centerY);
    make.left.equalTo(sv2.mas_right).with.offset(padding1);
    make.right.equalTo(sv.mas_right).with.offset(-padding1);
    make.height.mas_equalTo(@150);
    make.width.equalTo(sv2);
}];

代碼效果

這里我們在兩個子view之間互相設置的約束可以看到他們的寬度在約束下自動的被計算出來了

4. [中級] 在UIScrollView順序排列一些view并自動計算contentSize

UIScrollView *scrollView = [UIScrollView new];
scrollView.backgroundColor = [UIColor whiteColor];
[sv addSubview:scrollView];
[scrollView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(sv).with.insets(UIEdgeInsetsMake(5,5,5,5));
}];
UIView *container = [UIView new];
[scrollView addSubview:container];
[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(scrollView);
    make.width.equalTo(scrollView);
}];
int count = 10;
UIView *lastView = nil;
for ( int i = 1 ; i <= count ; ++i )
{
    UIView *subv = [UIView new];
    [container addSubview:subv];
    subv.backgroundColor = [UIColor colorWithHue:( arc4random() % 256 / 256.0 )
                                      saturation:( arc4random() % 128 / 256.0 ) + 0.5
                                      brightness:( arc4random() % 128 / 256.0 ) + 0.5
                                           alpha:1];
     
    [subv mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.and.right.equalTo(container);
        make.height.mas_equalTo(@(20*i));
         
        if ( lastView )
        {
            make.top.mas_equalTo(lastView.mas_bottom);
        }
        else
        {
            make.top.mas_equalTo(container.mas_top);
        }
    }];
     
    lastView = subv;
}
[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.bottom.equalTo(lastView.mas_bottom);
}];

頭部效果

尾部效果

從scrollView的scrollIndicator可以看出 scrollView的內部已如我們所想排列好了

這里的關鍵就在于container這個view起到了一個中間層的作用能夠自動的計算uiscrollView的contentSize

5. [高級] 橫向或者縱向等間隙的排列一組view

很遺憾 autoLayout并沒有直接提供等間隙排列的方法(Masonry的官方demo中也沒有對應的案例) 但是參考案例3 我們可以通過一個小技巧來實現這個目的為此我寫了一個Category

@implementation UIView(Masonry_LJC)
- (void) distributeSpacingHorizontallyWith:(NSArray*)views
{
    NSMutableArray *spaces = [NSMutableArray arrayWithCapacity:views.count+1];
     
    for ( int i = 0 ; i < views.count+1 ; ++i )
    {
        UIView *v = [UIView new];
        [spaces addObject:v];
        [self addSubview:v];
         
        [v mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.equalTo(v.mas_height);
        }];
    }    
     
    UIView *v0 = spaces[0];
     
    __weak __typeof(&*self)ws = self;
     
    [v0 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(ws.mas_left);
        make.centerY.equalTo(((UIView*)views[0]).mas_centerY);
    }];
     
    UIView *lastSpace = v0;
    for ( int i = 0 ; i < views.count; ++i )
    {
        UIView *obj = views[i];
        UIView *space = spaces[i+1];
         
        [obj mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(lastSpace.mas_right);
        }];
         
        [space mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(obj.mas_right);
            make.centerY.equalTo(obj.mas_centerY);
            make.width.equalTo(v0);
        }];
         
        lastSpace = space;
    }
     
    [lastSpace mas_makeConstraints:^(MASConstraintMaker *make) {
        make.right.equalTo(ws.mas_right);
    }];
     
}
- (void) distributeSpacingVerticallyWith:(NSArray*)views
{
    NSMutableArray *spaces = [NSMutableArray arrayWithCapacity:views.count+1];
     
    for ( int i = 0 ; i < views.count+1 ; ++i )
    {
        UIView *v = [UIView new];
        [spaces addObject:v];
        [self addSubview:v];
         
        [v mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.equalTo(v.mas_height);
        }];
    }
     
     
    UIView *v0 = spaces[0];
     
    __weak __typeof(&*self)ws = self;
     
    [v0 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(ws.mas_top);
        make.centerX.equalTo(((UIView*)views[0]).mas_centerX);
    }];
     
    UIView *lastSpace = v0;
    for ( int i = 0 ; i < views.count; ++i )
    {
        UIView *obj = views[i];
        UIView *space = spaces[i+1];
         
        [obj mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(lastSpace.mas_bottom);
        }];
         
        [space mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(obj.mas_bottom);
            make.centerX.equalTo(obj.mas_centerX);
            make.height.equalTo(v0);
        }];
         
        lastSpace = space;
    }
     
    [lastSpace mas_makeConstraints:^(MASConstraintMaker *make) {
        make.bottom.equalTo(ws.mas_bottom);
    }];
}
@end

簡單的來測試一下

UIView *sv11 = [UIView new];
UIView *sv12 = [UIView new];
UIView *sv13 = [UIView new];
UIView *sv21 = [UIView new];
UIView *sv31 = [UIView new];
sv11.backgroundColor = [UIColor redColor];
sv12.backgroundColor = [UIColor redColor];
sv13.backgroundColor = [UIColor redColor];
sv21.backgroundColor = [UIColor redColor];
sv31.backgroundColor = [UIColor redColor];
[sv addSubview:sv11];
[sv addSubview:sv12];
[sv addSubview:sv13];
[sv addSubview:sv21];
[sv addSubview:sv31];
//給予不同的大小 測試效果
[sv11 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.equalTo(@[sv12,sv13]);
    make.centerX.equalTo(@[sv21,sv31]);
    make.size.mas_equalTo(CGSizeMake(40, 40));
}];
[sv12 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(70, 20));
}];
[sv13 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(50, 50));
}];
[sv21 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(50, 20));
}];
[sv31 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(40, 60));
}];
[sv distributeSpacingHorizontallyWith:@[sv11,sv12,sv13]];
[sv distributeSpacingVerticallyWith:@[sv11,sv21,sv31]];
[sv showPlaceHolderWithAllSubviews];
[sv hidePlaceHolder];