CODEWITHSUNDEEP
iphoneuiscrollviewuibuttonlag
Sebastian Søndergaard
Sebastian Søndergaard

Reputation: 59

UIScrollView lags on iPhone

I'm trying to create a crossword app. The game runs in a UIScrollView, because the player should be able to zoom, scroll etc. The largest crossword are 21x21 which means there need to be 441 touchable tiles. What i've tried so far were to create an UIView and added it as a subView to the UIScrollView. Then I call a method that creates 441 custom UIButtons and set the backgroundImage.

Some of the UIButtons need to have a custom label overlay, so i added a UILabel and set it on top of the UIButton.

When I run the app in simulator all works as it should, but when i test it on an iPhone 4 the UIScrollView lags a lot.

I don't know if this the way to do it? Can you maybe try to guide me in the right direction of how to do this so the UIScrollView won't lag on a device.

Thanks in advance.

Upvotes: 0

Views: 914

Answers (2)

Paul Hunter
Paul Hunter

Reputation: 4463

Big UIScrollViews are difficult to make smooth without some sort of caching mechanism, such as the one provided by UITableView.

One thing you can do, however, to make life easier for your rendering, is to make sure to use opaque backgrounds whenever possible. In stead of making a view transparent you should make it the same color as its underlying view. This is something that does help.

Also, I have experienced better performance using imageWithContentsOfFile: in stead of imageNamed: for initializing images to be used in a UIScrollView.

Upvotes: 1

Demz
Demz

Reputation: 1058

In order to not keep all those buttons in memory, you should work with reusable table view cells, this will really improve the scroll performance. Here's one component that could make your life easier: DTGridView, there are also others (you can check Cocoa Controls)

Upvotes: 0

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