What is the most robust way to force a UIView to redraw?

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I have a UITableView with a list of items. Selecting an item pushes a viewController that then proceeds to do the following. from method viewDidLoad I fire off a URLRequest for data that is required by on of my subviews - a UIView subclass with drawRect overridden. When the data arrives from the cloud I start building my view hierarchy. the subclass in question gets passed the data and it's drawRect method now has everything it needs to render.

But.

Because I don't call drawRect explicitly - Cocoa-Touch handles that - I have no way of informing Cocoa-Touch that I really, really want this UIView subclass to render. When? Now would be good!

I've tried [myView setNeedsDisplay]. This kinda works sometimes. Very spotty.

I've be wrestling with this for hours and hours. Could someone who please provide me with a rock solid, guaranteed approach to forcing a UIView re-render.

Here is the snippet of code that feeds data to the view:

// Create the subview
self.chromosomeBlockView = [[[ChromosomeBlockView alloc] initWithFrame:frame] autorelease];

// Set some properties
self.chromosomeBlockView.sequenceString     = self.sequenceString;
self.chromosomeBlockView.nucleotideBases    = self.nucleotideLettersDictionary;

// Insert the view in the view hierarchy
[self.containerView          addSubview:self.chromosomeBlockView];
[self.containerView bringSubviewToFront:self.chromosomeBlockView];

// A vain attempt to convince Cocoa-Touch that this view is worthy of being displayed ;-)
[self.chromosomeBlockView setNeedsDisplay];

Cheers, Doug

urlrequest uiview cocoa-touch
6 Answers

You can use CATransaction to force a redraw:

[CATransaction begin];
[someView.layer displayIfNeeded];
[CATransaction flush];
[CATransaction commit];
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