xcode6 的自动布局问题

Question

xcode布局

Answer 1

自动布局autolayout 会帮你管理在各个尺寸设备下的显示，前提是你正确设置了各元素的约束。使用自动布局后不需要再调整，因为它就是为解决这种问题而出现的。

Answer 2

- (void)setupView
{
    self.backgroundColor = [UIColor whiteColor];
    self.accessoryType = UITableViewCellAccessoryNone;
    self.accessoryView = nil;
    self.selectionStyle = UITableViewCellSelectionStyleNone;
    // Fix for contentView constraint warning
    [self.contentView setAutoresizingMask:UIViewAutoresizingFlexibleHeight];
    
    // Create our ImageView
    self.sampleImageView = [[UIImageView alloc] initWithFrame:CGRectZero];
    self.sampleImageView.translatesAutoresizingMaskIntoConstraints = NO;
    self.sampleImageView.contentMode = UIViewContentModeScaleAspectFit;
    self.sampleImageView.layer.borderColor = [UIColor colorWithWhite:210.0/255 alpha:1.0].CGColor;
    self.sampleImageView.layer.borderWidth = 0.5;
    self.sampleImageView.backgroundColor = [UIColor whiteColor];
    [self.contentView addSubview:self.sampleImageView];
    
    // title label
    self.titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    self.titleLabel.translatesAutoresizingMaskIntoConstraints = NO;
    self.titleLabel.font = [UIFont systemFontOfSize:15];
    self.titleLabel.textColor = [UIColor colorWithRed:50.0/255 green:50.0/255 blue:50.0/255 alpha:1.0];
    self.titleLabel.numberOfLines = 1;
    //self.titleLabel.lineBreakMode = NSLineBreakByWordWrapping;
    [self.contentView addSubview:self.titleLabel];    
    //discass label
    self.discassLabel = [[UILabel alloc]initWithFrame:CGRectZero];
    self.discassLabel.translatesAutoresizingMaskIntoConstraints = NO;
    self.discassLabel.font = [UIFont systemFontOfSize:12];
    self.discassLabel.textColor = [UIColor grayColor];
    self.discassLabel.numberOfLines = 1;
    [self.contentView addSubview:self.discassLabel];
    
    //discass image view
    self.disImageView = [[UIImageView alloc]initWithFrame:CGRectZero];
    self.disImageView.translatesAutoresizingMaskIntoConstraints = NO;
    self.disImageView.contentMode = UIViewContentModeScaleAspectFill;
    self.disImageView.backgroundColor = [UIColor clearColor];
    //self.disImageView.image = [UIImage imageNamed:@"comment.png"];
    [self.contentView addSubview:self.disImageView];
    
    CGFloat width = CGRectGetWidth([UIScreen mainScreen].bounds) - 22;
    CGFloat height = width*18.0/29.0;    // Constrain
    NSDictionary *viewDict = NSDictionaryOfVariableBindings(_sampleImageView,_titleLabel,_disImageView,_discassLabel);
    // Create a dictionary with buffer values
    NSDictionary *metricDict = @{@"sideBuffer" : @11, @"verticalBuffer" : @6, @"midBuffer" : @5, @"imageWidth" : [NSNumber numberWithFloat:width],@"imageHeight" : [NSNumber numberWithFloat:height],@"smallicon" : @15};
    
    // Constrain elements horizontally
    [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-sideBuffer-[_sampleImageView(imageWidth)]" options:0 metrics:metricDict views:viewDict]];
    [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[_disImageView(smallicon)]-midBuffer-[_discassLabel]-smallicon-|" options:0 metrics:metricDict views:viewDict]];
    [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-smallicon-[_titleLabel]-(50)-|" options:0 metrics:metricDict views:viewDict]];
    // Constrain elements vertically
    [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-verticalBuffer-[_sampleImageView(imageHeight)]" options:0 metrics:metricDict views:viewDict]];
    [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[_disImageView(sideBuffer)]" options:0 metrics:metricDict views:viewDict]];
    
    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.titleLabel attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.sampleImageView attribute:NSLayoutAttributeBottom multiplier:1 constant:5]];
    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.disImageView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.titleLabel attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]];
    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.discassLabel attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.titleLabel attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]];    
    [self.discassLabel setContentCompressionResistancePriority:UILayoutPriorityDefaultHigh forAxis:UILayoutConstraintAxisHorizontal];
    [self.disImageView setContentCompressionResistancePriority:UILayoutPriorityDefaultHigh forAxis:UILayoutConstraintAxisHorizontal];
    [self.titleLabel setContentCompressionResistancePriority:UILayoutPriorityDefaultLow forAxis:UILayoutConstraintAxisHorizontal];
}
动态自动布局你可以这样,不懂的方法自己百度....

Answer 3

如果是动态布局的话，比如Cell，我一般会把某个需要动态的约束用IBOutlet连接到类里，然后通过修改它的constant值来修改约束