NSLayoutConstraint的簡單應用，nslayoutconstraint

NSLayoutConstraint的簡單應用，nslayoutconstraint

    UIView *topView = [[UIView alloc] init];    topView.backgroundColor = [UIColor redColor];    [self.view addSubview:topView];    topView.translatesAutoresizingMaskIntoConstraints = NO;    [self.view addConstraints:@[                                                                [NSLayoutConstraint constraintWithItem:topView                                                             attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1.0 constant:10],                                [NSLayoutConstraint constraintWithItem:topView                                                             attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1.0 constant:-10],                                [NSLayoutConstraint constraintWithItem:topView                                                             attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:100],                                [NSLayoutConstraint constraintWithItem:topView                                                             attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:20]                                ]];

 

 topView在父視圖的左邊間距10，下邊間距-10，寬度為100，高度為20的實現代碼