我认为这是自动布局的问题。
我创建了一个视图，并在其中创建了一些子视图。
内容视图包含子视图，子视图全部放在一行中。
我认为我没有做错什么，但内容视图的框架始终不正确。
像这样：2013-08-29 14:13:34.688 AutoLayoutBugTest[4658:c07] pV_content.frame {{0, 208}, {319, 44}}
内容视图的宽度是319而不是320，更改viewDidLoad函数中的'cnt'参数，帧可能更差。
像这样的代码：@interface ViewController ()
@property (nonatomic, strong) UIView *pV_content;
@property (nonatomic, strong) NSMutableArray *Arr_views;
@end
@implementation ViewController
- (void)removeConstraintForCustomView:(UIView *)customView
fromView:(UIView *)superView
{
NSMutableArray *pArr_constraint = [NSMutableArray array];
for (NSLayoutConstraint *constraint in superView.constraints) {
if ([constraint.firstItem isEqual:customView]) {
[pArr_constraint addObject:constraint];
}
}
[superView removeConstraints:pArr_constraint];
pArr_constraint = nil;
}
- (void)constraintCustomView:(UIView *)customView
matchWidthOfView:(UIView *)superView
withHeight:(CGFloat)height
{
[self removeConstraintForCustomView:customView fromView:superView];
customView.translatesAutoresizingMaskIntoConstraints = NO;
NSLayoutConstraint *constraint_y = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeCenterY
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeCenterY
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_y];
NSLayoutConstraint *constraint_height = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeHeight
multiplier:0.f
constant:height];
[superView addConstraint:constraint_height];
NSLayoutConstraint *constraint_left = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeLeft
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_left];
NSLayoutConstraint *constraint_width = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeWidth
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_width];
}
- (void)constraintCustomView:(UIView *)customView
matchWidthPercentOfView:(UIView *)superView
boxCount:(int)boxCount
boxIndex:(int)boxIndex
{
[self removeConstraintForCustomView:customView fromView:superView];
customView.translatesAutoresizingMaskIntoConstraints = NO;
NSLayoutConstraint *constraint_top = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeTop
multiplier:1.f
constant:customView.frame.origin.y];
[superView addConstraint:constraint_top];
constraint_top.priority = UILayoutPriorityFittingSizeLevel;
NSLayoutConstraint *constraint_height = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeHeight
multiplier:0.f
constant:customView.frame.size.height];
[superView addConstraint:constraint_height];
constraint_height.priority = UILayoutPriorityFittingSizeLevel;
if (boxCount == 1) {
NSLayoutConstraint *constraint_percent_x = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeCenterX
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_percent_x];
constraint_percent_x.priority = UILayoutPriorityFittingSizeLevel;
NSLayoutConstraint *constraint_width = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeWidth
multiplier:1.f
constant:-4.f];
[superView addConstraint:constraint_width];
constraint_width.priority = UILayoutPriorityFittingSizeLevel;
}
else {
if (boxIndex == 0) {
NSLayoutConstraint *constraint_left = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeLeft
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_left];
constraint_left.priority = UILayoutPriorityFittingSizeLevel;
NSLayoutConstraint *constraint_width = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeWidth
multiplier:(2.f / (CGFloat)(2 * boxCount + 1))
constant:-2.f];
[superView addConstraint:constraint_width];
constraint_width.priority = UILayoutPriorityFittingSizeLevel;
}
else if (boxIndex == boxCount - 1) {
NSLayoutConstraint *constraint_right = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeRight
multiplier:1.f
constant:0.f];
[superView addConstraint:constraint_right];
constraint_right.priority = UILayoutPriorityFittingSizeLevel;
NSLayoutConstraint *constraint_width = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeWidth
multiplier:(2.f / (CGFloat)(2 * boxCount + 1))
constant:-2.f];
[superView addConstraint:constraint_width];
constraint_width.priority = UILayoutPriorityFittingSizeLevel;
}
else {
NSLayoutConstraint *constraint_percent_x = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeCenterX
multiplier:(((CGFloat)(2 * boxIndex + 1)) / (CGFloat)boxCount)
constant:0.f];
[superView addConstraint:constraint_percent_x];
constraint_percent_x.priority = UILayoutPriorityFittingSizeLevel;
NSLayoutConstraint *constraint_width = [NSLayoutConstraint constraintWithItem:customView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:superView
attribute:NSLayoutAttributeWidth
multiplier:(2.f / (CGFloat)(2 * boxCount + 1))
constant:-2.f];
[superView addConstraint:constraint_width];
constraint_width.priority = UILayoutPriorityFittingSizeLevel;
}
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.view.backgroundColor = [UIColor whiteColor];
self.pV_content = [[UIView alloc] initWithFrame:CGRectMake(0.f,
0.f,
self.view.frame.size.width,
44.f)];
self.pV_content.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:self.pV_content];
[self constraintCustomView:self.pV_content
matchWidthOfView:self.view
withHeight:44.f];
int cnt = 5;
for (int i = 0; i < cnt; i++) {
UIView *pV_sub = [[UIView alloc] initWithFrame:CGRectMake(0.f,
5.f,
30.f,
35.f)];
pV_sub.backgroundColor = [UIColor redColor];
[self.pV_content addSubview:pV_sub];
[self constraintCustomView:pV_sub
matchWidthPercentOfView:self.pV_content
boxCount:cnt
boxIndex:i];
}
}
- (void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
NSLog(@"pV_content.frame %@", NSStringFromCGRect(self.pV_content.frame));
}
- (BOOL)shouldAutorotate
{
return YES;
}
- (NSUInteger)supportedInterfaceOrientations
{
return UIInterfaceOrientationMaskAll;
}
@end
答案 0 :(得分：0)
来自指南：
约束的形式为“view1.attr1 view2.attr2 * multiplier + constant”。如果您希望表达的约束没有第二个视图和属性，请使用nil和NSLayoutAttributeNotAnAttribute。
次要：尝试使用
constraintsWithVisualFormat:options:metrics:views:
例如，如果您有一个视图testView：
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[testView]|" options:0 metrics:0 views:@{@"testView":self.testView}]];