一、AutoLayout有兩個重要的屬性：

1.Content Compression Resistance 百度翻譯（內容壓縮抗力）
2.Content Hugging 百度翻譯(內容擁抱)

二、解釋

Content Compression Resistance = 變大！（保持自己更大）

這個屬性的優先級（Priority）越高，越不“容易”被壓縮。也就是說，當整體的空間裝不下所有的View的時候，Content Compression Resistance優先級越高的，現實的內容越完整。

[self.labelTwo setContentCompressionResistancePriority:UILayoutPriorityDefaultHighforAxis:UILayoutConstraintAxisHorizontal];

Content Hugging = 抱緊！（保持自己更?。?

這個屬性的優先級越高，整個View就要越“抱緊”View里面的內容。也就是View的大小不會隨著父級View的擴大而擴大。

[self.labelOne setContentHuggingPriority:UILayoutPriorityDefaultHighforAxis:UILayoutConstraintAxisHorizontal];

 >參數一：(UILayoutPriority)
 >設置優先級等級，數值越大，優先級越高。
 >UILayoutPriorityRequired           == 1000；
 >UILayoutPriorityDefaultHigh        == 750；
 >UILayoutPriorityDefaultLow         == 250；
 >UILayoutPriorityFittingSizeLevel   == 50；


>參數二：(UILayoutConstraintAxis)
>百度翻譯(Axis：軸線。意思是你添加的優先級是Horizontal還是Vertical)
 >UILayoutConstraintAxisHorizontal
 >UILayoutConstraintAxisVertical

三、代碼部分

#import "ViewController.h"
#import "Masonry.h"

@interface ViewController ()

@property(nonatomic,strong) UILabel * labelOne;
@property(nonatomic,strong) UILabel * labelTwo;

@end

@implementation ViewController


- (void)initUI
{
    [self.view addSubview:self.labelOne];
    [self.labelOne mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.view.mas_left).with.offset(20);
        make.top.equalTo(self.view.mas_top).with.offset(20);
    }];
    
    [self.view addSubview:self.labelTwo];
    [self.labelTwo mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(_labelOne.mas_right);
        make.right.equalTo(self.view.mas_right);
        make.top.equalTo(self.view.mas_top).with.offset(20);
        make.height.equalTo(_labelOne);
    }];
    
    [self.labelOne setContentHuggingPriority:UILayoutPriorityDefaultHigh forAxis:UILayoutConstraintAxisHorizontal];
    /**參數一：(UILayoutPriority)
     UILayoutPriorityRequired
     UILayoutPriorityDefaultHigh
     UILayoutPriorityDefaultLow
     UILayoutPriorityFittingSizeLevel
     */
    
    /**參數二：(UILayoutConstraintAxis)
     UILayoutConstraintAxisHorizontal
     UILayoutConstraintAxisVertical
     */
    [self.labelTwo setContentCompressionResistancePriority:UILayoutPriorityDefaultHigh forAxis:UILayoutConstraintAxisHorizontal];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    [self initUI];
}

- (UILabel *)labelOne{
    if (!_labelOne) {
        self.labelOne = [[UILabel alloc] init];
        self.labelOne.text = @"這是labelOne";
        self.labelOne.backgroundColor = [UIColor redColor];
    }
    return _labelOne;
}

- (UILabel *)labelTwo{
    if (!_labelTwo) {
        self.labelTwo = [[UILabel alloc] init];
        self.labelTwo.text = @"這是labelTwo";
        self.labelTwo.backgroundColor = [UIColor greenColor];
    }
    return _labelTwo;
}
@end

尊重原創