Wrestling with Car Format tin beryllium a thrilling drive, afloat of sudden twists and turns. 1 of the about communal caput-scratchers is the enigmatic UIView-Encapsulated-Format-Tallness constraint. What is it? Wherefore does it look seemingly retired of obscurity? And, about importantly, however tin you tame this beast and unit it to recalculate accurately, giving you the structure you meticulously crafted? This station dives heavy into the mysteries of UIView-Encapsulated-Structure-Tallness, offering actionable methods to conquer your Car Structure woes and accomplish pixel-clean UI concord.
Demystifying UIView-Encapsulated-Format-Tallness
UIView-Encapsulated-Structure-Tallness is a scheme-generated constraint that represents the intrinsic contented tallness of a UIView. It’s robotically added once Car Format wants to find the tallness of a position based mostly connected its contented, particularly once the position doesn’t person express tallness constraints. Deliberation of it arsenic Car Format’s manner of saying, “I’ve calculated the tallness based mostly connected what’s wrong this position.” This frequently occurs with UILabels, UIButtons, and UIStackViews wherever the contented dictates the measurement.
This constraint is mostly adjuvant, however it tin go problematic once your structure expectations conflict with the scheme’s calculations. This tin pb to surprising format behaviour, together with clipping, overlapping parts, and the dreaded “ambiguous format” warnings and errors. Knowing however this constraint plant is important for debugging and resolving these points.
Communal Causes of UIView-Encapsulated-Structure-Tallness Conflicts
Respective situations tin set off conflicts involving UIView-Encapsulated-Structure-Tallness. 1 communal perpetrator is conflicting constraints. For illustration, if you fit a fastened tallness constraint connected a UILabel that’s besides relying connected its intrinsic contented dimension, you’ll apt brush a struggle.
Different predominant origin is incorrect UIStackView configuration. If you haven’t decently outlined the organisation and alignment properties, the stack position mightiness make conflicting constraints, together with the encapsulated format tallness constraint. Likewise, forgetting to fit the numberOfLines place to zero connected a multi-formation UILabel tin besides pb to sudden tallness calculations and conflicts.
- Conflicting specific tallness constraints.
- Incorrect UIStackView configuration.
Taming the Beast: Forcing Recalculation
Present, fto’s acquire to the bosom of the substance: however to unit UIView-Encapsulated-Format-Tallness to recalculate cleanly. Respective methods tin aid you regain power of your format. 1 effectual technique is calling setNeedsLayout() and layoutIfNeeded() connected the affected position. setNeedsLayout() marks the position arsenic needing a format replace, piece layoutIfNeeded() forces the structure replace instantly. This tin beryllium particularly utile once dealing with dynamic contented adjustments.
Different attack is to invalidate the intrinsic contented dimension of the position by overriding the intrinsicContentSize place. This tells Car Format to recalculate the dimension primarily based connected the actual contented. Nevertheless, usage this with warning, arsenic it tin pb to show points if overused.
- Call
setNeedsLayout()andlayoutIfNeeded(). - Override
intrinsicContentSize.
Champion Practices for a Harmonious Format
Stopping UIView-Encapsulated-Structure-Tallness conflicts successful the archetypal spot is ever the champion scheme. Cautiously reappraisal your constraints and guarantee they don’t struggle with the intrinsic contented dimension of your views. Treble-cheque your UIStackView configurations and guarantee they are fit ahead appropriately. For multi-formation labels, ever retrieve to fit numberOfLines to zero.
Totally investigating your structure crossed antithetic surface sizes and orientations is important. Usage Xcode’s preview characteristic and trial connected animal gadgets to drawback immoderate possible format points aboriginal connected. By pursuing these champion practices, you tin reduce the probabilities of encountering UIView-Encapsulated-Structure-Tallness issues and make sturdy, adaptable layouts.
Arsenic Pome’s documentation states, “Constraints correspond relationships betwixt views.” Knowing these relationships is cardinal to mastering Car Structure.
- Reappraisal constraints for conflicts.
- Treble-cheque UIStackView configurations.
Larn much astir Car Structure champion practices.Featured Snippet: UIView-Encapsulated-Structure-Tallness is a scheme-generated constraint representing a position’s intrinsic contented tallness. Conflicts originate once express constraints conflict with this calculated tallness. Options see calling setNeedsLayout()/layoutIfNeeded() oregon overriding intrinsicContentSize. Prevention is cardinal: reappraisal constraints, confirm UIStackView setup, and trial completely.
[Infographic Placeholder] FAQs
Q: What is the quality betwixt setNeedsLayout() and layoutIfNeeded()?
A: setNeedsLayout() schedules a structure replace for the adjacent render rhythm, piece layoutIfNeeded() forces the structure replace instantly.
Running with Car Format and constraints tin beryllium difficult, however by knowing the intricacies of UIView-Encapsulated-Structure-Tallness and using the methods outlined present, you tin make dynamic, responsive UIs that accommodate seamlessly to antithetic surface sizes and orientations. Retrieve to prioritize cautious readying, thorough investigating, and proactive debugging. These practices volition not lone resoluteness present format points however besides forestall early complications, redeeming you invaluable improvement clip and starring to a smoother, much satisfying Car Structure education. Dive deeper into constraint debugging with these adjuvant assets: Pome’s setNeedsLayout Documentation, Pome’s layoutIfNeeded Documentation, and Stack Overflow - Car Structure. See exploring associated matters similar contented hugging and compression opposition priorities for equal finer power complete your layouts.
Question & Answer :
I person a UITableView moving nether iOS eight and I’m utilizing automated compartment heights from constraints successful a storyboard.
1 of my cells accommodates a azygous UITextView and I demand it to declaration and grow based mostly connected person enter - pat to shrink/grow the matter.
I’m doing this by including a runtime constraint to the matter position and altering the changeless connected the constraint successful consequence to person occasions:
-(void)illness:(BOOL)illness; { _collapsed = illness; if(illness) [_collapsedtextHeightConstraint setConstant: kCollapsedHeight]; // 70.zero other [_collapsedtextHeightConstraint setConstant: [same idealCellHeightToShowFullText]]; [same setNeedsUpdateConstraints]; }
Whenver I bash this, I wrapper it successful tableView updates and call [tableView setNeedsUpdateConstraints]:
[tableView beginUpdates]; [_briefCell illness:!_showFullBriefText]; [tableView setNeedsUpdateConstraints]; // I person besides tried // [same.tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationTop]; // with precisely the aforesaid outcomes. [tableView endUpdates];
Once I bash this, my compartment does grow (and animates while doing it) however I acquire a constraints informing:
2014-07-31 thirteen:29:fifty one.792 OneFlatEarth[5505:730175] Incapable to concurrently fulfill constraints. Most likely astatine slightest 1 of the constraints successful the pursuing database is 1 you don't privation. Attempt this: (1) expression astatine all constraint and attempt to fig retired which you don't anticipate; (2) discovery the codification that added the undesirable constraint oregon constraints and hole it. (Line: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't realize, mention to the documentation for the UIView place translatesAutoresizingMaskIntoConstraints) ( "<NSLayoutConstraint:0x7f94dced2b60 V:[UITextView:0x7f94d9b2b200'Little matter: Lorem Ipsum i...'(388)]>", "<NSLayoutConstraint:0x7f94dced2260 V:[UITextView:0x7f94d9b2b200'Little matter: Lorem Ipsum i...']-(15)-| (Names: '|':UITableViewCellContentView:0x7f94de5773a0 )>", "<NSLayoutConstraint:0x7f94dced2350 V:|-(6)-[UITextView:0x7f94d9b2b200'Little matter: Lorem Ipsum i...'] (Names: '|':UITableViewCellContentView:0x7f94de5773a0 )>", "<NSLayoutConstraint:0x7f94dced6480 'UIView-Encapsulated-Structure-Tallness' V:[UITableViewCellContentView:0x7f94de5773a0(ninety one)]>" ) Volition effort to retrieve by breaking constraint <NSLayoutConstraint:0x7f94dced2b60 V:[UITextView:0x7f94d9b2b200'Little matter: Lorem Ipsum i...'(388)]>
388 is my calculated tallness, the another constraints connected the UITextView are excavation from Xcode/IB.
The last 1 is bothering maine - I’m guessing that UIView-Encapsulated-Structure-Tallness is the calculated tallness of the compartment once it is archetypal rendered - (I fit my UITextView tallness to beryllium >= 70.zero) nevertheless it doesn’t look correct that this derived constraint past overrules an up to date person cnstraint.
Worse, though the format codification says it’s making an attempt to interruption my tallness constraint, it doesn’t - it goes connected to recalculate the compartment tallness and every little thing attracts arsenic I would similar.
Truthful, what is NSLayoutConstraint UIView-Encapsulated-Format-Tallness (I’m guessing it is the calculated tallness for computerized compartment sizing) and however ought to I spell astir forcing it to recalculate cleanly?
Attempt to less the precedence of your _collapsedtextHeightConstraint to 999. That manner the scheme equipped UIView-Encapsulated-Format-Tallness constraint ever takes priority.
It is based mostly connected what you instrument successful -tableView:heightForRowAtIndexPath:. Brand certain to instrument the correct worth and your ain constraint and the generated 1 ought to beryllium the aforesaid. The less precedence for your ain constraint is lone wanted briefly to forestall conflicts piece illness/grow animations are successful formation.
Summation: Piece it whitethorn beryllium debatable if the scheme provided constraint is accurate oregon not, location’s nary component successful warring the model. Merely judge that the scheme constraint takes priority. If you deliberation the scheme constraint is incorrect, brand certain to instrument the accurate rowHeight from the delegate.
