cocoa-touch - 使用自动布局视觉格式字符串均匀分布间距

Question

b是否可以平均分配左右空间在 @"|-[a(5)]-[b(8)]-[c(5)]-|"使用视觉格式字符串？

Answer 1

苹果Auto Layout Guide建议使用“间隔 View ”。这是在水平方向上以相等的间距布置三个 View 的解决方案:

// create views dictionary
NSMutableDictionary *viewsDictionary = [NSMutableDictionary dictionary];
[viewsDictionary addEntriesFromDictionary:NSDictionaryOfVariableBindings(viewA, viewB, viewC)];

// create 4 spacer views
for (int i = 0; i < 4; i++) {
    UIView *spacerView = [[UIView alloc] init];
    spacerView.hidden = YES;
    [self addSubview:spacerView];
    [viewsDictionary setObject:spacerView
                        forKey:[NSString stringWithFormat:@"spacer%d", i + 1]];
}

// disable translatesAutoresizingMaskIntoConstraints in views for auto layout
[viewsDictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) 
{
    [obj setTranslatesAutoresizingMaskIntoConstraints:NO];
}];

// add constraints
[superview addConstraints:
 [NSLayoutConstraint constraintsWithVisualFormat:
  @"|[spacer1(>=0)][viewA][spacer2(==spacer1)][viewB][spacer3(==spacer1)][viewC][spacer4(==spacer1)]|"
                                         options:kNilOptions
                                         metrics:nil
                                           views:viewsDictionary]];

请注意 spacer1的宽度设置为大于 0。随后的间隔 View 设置为与 spacer1 具有相同的宽度.