I have iOS 6 application that consists of UIView with many UIButtons (like 9 to as many as 100) displayed at same time; all buttons are movable, so I'm changing button's frame property all the time.
After using the application for a couple of minutes (= moving buttons around the parent UIView), app slows down. It is very strange also that it seems buttons that are near the bottom of the screen (= parent UIView) are much slower than those on the top of screen.
All buttons belong to same class, inherited from generic UIButton.
It happens only on real device, not iPhone simulator.
Any idea about the issue? I'm using NSlog frequently through the code. Can this be the problem?
Thx,
DJ
You can set your NSLogs to be only in DEBUG mode, it will be much faster in Relese:
#ifdef DEBUG
NSLog(#"log");
#endif
Yes you are right.
Never give NSLog or DLog in release versions..
remove all nslog, or for testing purpose just comment them out.
#ifdef DEBUG
NSLog(#"log");
#endif
or
#define NSLog //NSLog
Also you should check for zombies and memory leaks.
Related
Hei.
These two pictures below show what changed. Here's my code for it and the code didn't change.
- (NSString *)tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section
{
if (section == 0) {
return #"If enabled, closing apps via the app switcher won't actually close the app itself.\n\nThis option is perfect to use with Fast Freeze.";
}
NSString *offDescription = #"OFF\nDisables the backgrounding capability completely. The app has to restart every time you close it.";
NSString *fastFreezeDescription = #"FAST FREEZE\nThis mode is similar to what 'Smart Close' by rpetrich did. Usually an app has up to 10 minutes to perform tasks in the background before it gets suspended in memory. Since this can be an unnecessary battery drain, Fast Freeze will suspend the app right after you close it.";
NSString *nativeDescription = #"NATIVE\nThis is Apple's built in way of backgrounding.";
NSString *unlimitedNativeDescription = #"UNLIMITED NATIVE\nThis background mode allows apps to execute background tasks for an unlimited period of time, so the app won't get suspended in memory after 10 minutes.";
NSString *foregroundDescription = #"FOREGROUND\nForeground tricks the system into thinking that the app wasn't closed and is still running in foreground. This is the perfect way to continue to listen to internet streams or videos while using another app.";
return [NSString stringWithFormat:#"\n%#\n\n%#\n\n%#\n\n%#\n\n%#", offDescription, fastFreezeDescription, nativeDescription, unlimitedNativeDescription, foregroundDescription];
}
Here are the screenshots:
This is the view before (iOS 8), notice that "\nOFF\nDisables ..." has the gap to the last UITableViewCell like it should be.
This is the view after (iOS 9), the gap is off. Too much space there.
So, does anyone know why this happens? If anyone has an fix or something, please tell me!
Thanks in advance!
This seems like an Apple's bug (iOS 9.0 - 9.1), the more lines footer has, the bigger misplacement gets.
You can even reproduce this in the storyboard using static table view.
I cound't find any workaround yet, the best advice I can give is to file a bug report to Apple.
Update
The bug in storyboard seems to be fixed in Xcode 7.2 beta 2. However this issue still persists when you run the app even on iOS 9.2 simulator.
Update 2
Narrowed down the reproduction of this bug. Basically something breaks after your app presents a table view section header. Check this repo for details.
I'm trying to solve a memory leak in my iOS app and struggling. I'm using the leaks tool to try to isolate the problem. To my surprise, the leak seems to be happening 100% within the UITableView gesture recognizer code. Specifically, the leak count increments each time I stop scrolling (release) the UITableView. Even weirder, this happens with a UIWebView as well. And with a UIScrollView.
So each time I release a drag action on any of these UIKit objects, I get a memory leak. The UI pieces are at different, distinct places around my app, so it's not just localized to one screen.
Ideas?
I just started doing iPhone dev. At the moment I'm trying to fix a bug which exists in an already built app. The main function looks as follows:
#import <UIKit/UIKit.h>
int main(int argc, char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, nil);
[pool release];
return retVal;
}
This seems pretty typical from what I understand; I'm guessing UIApplicationMain is the main loop, which the source files that have been created for the app specifically connects to via the use of delegates/function pointers in Objective-C (note, while I'm quite proficient in C++, I hardly know much about iOS or Objective-C).
So, what I'd like to know is how I can step through my source files and track down the calculation bug I'm experiencing for this app. Unfortunately, all I receive is disassembly when stepping into the UIApplicationMain, and while I know the very basics of asm and can interpret it (for the most part), I'd rather not unless I absolutely have to - especially considering the fact that the debugger appears to be outputting AT&T syntax (NOTE: if it's possible to change the asm syntax to Intel, I'd appreciate it if someone could state how to do that).
Thanks.
You can put breakpoints on every line by clicking on the gray space between the code and the project explorer on the left. When running, upon encountering a breakpoint the simulator or device will stop running and the code will show up. Then hit either the down arrow button that will show up on the upper left of the debugging window at the bottom to go line by line, which will show asm when appropriate, or hit the right-pointing arrow which will run until the next breakpoint is hit. You can disable breakpoints by deleting them individually or by toggling the breakpoints button at the top.
The main function in iOS is almost identical in all projects. It just serves to get the ball rolling. Here is a good tutorial for debugging especially crashes in Xcode. debugging tutorial
(Answer to NOTE not the actual question)
xcode can be set to use gdb (in scheme settings):
simply add to your .gdbinit
(which is located in your home dir ) :
"set disassembly-flavor intel"
for lldb there might be something similar
I'm testing my app on Instruments -> Leaks
And I have a leak that I can't eliminate, because I can't understand its roots.
What should I do?
P.S. These leaks appear after such steps:
App goes to background with visible keyboard.
App goes to foreground.
I enter any letter on the keyboard.
If the keyboard is invisible before going to background = no leaks
one http://iwheelbuy.com/leak.png
two http://iwheelbuy.com/leak1.png
three http://iwheelbuy.com/leak2.png
I will suggest in applicationWillEnterBackground in AppDelegate.h, just resign First responder.
At a great number of requests from people using older iOS hardware, I'm currently refactoring and optimizing my app so it will work on iOS 3. That being said I've got a glitch with my UITabBar that I can replicate on all of the iPhone 3G units I've tested it on.
The glitch appears to have been fixed in iOS 4, but I was wondering if before that time, anyone else had this glitch as well and had figured out a (relatively elegant) workaround for it.
The problem is what you can see below; when a memory warning occurs and all of the views offscreen are released, when I bring a view controller with a tab bar back on screen, all of the UITabBarItems that are supposed to be in it are gone. As far as I can see, they're not being drawn at all; ie tapping the tab bar has no effect. After setting breakpoints and examining the UITabBar and its items in memory, they're all still there (ie not getting released), just that they're not getting redrawn when the UITabBar is re-created in the controller loadView method.
My app works similar to the official Twitter app in that I implemented my own version of UITabBarController so I could control the integration of it with a parent UINavigationController properly. I set it up as closely as possible to the original UITabBarController class though, with all of the child view controllers handling their own respective UITabBarItems and initializing them inside the class' init methods. Once the child view controllers are passed to my TabController object via an accessor method, the tabBarItems are accessed and added to the UITabBar view.
Has anyone seen this behaviour before and know of a way I can fix it? I'm hoping there's a really simple fix for this since it already works in iOS 4, so I don't want to hack it up too badly.
Thanks a lot!
After a bit of research, I think I found a solution to this. It's not the most elegant solution I was after, but it definitely works.
I'm guessing after a memory warning is triggered, something is happening to the UITabBarItem objects that basically renders them corrupt. I tried a lot of things (flushing out the UITabBar, re-creating the controllers array etc), but nothing worked.
I finally discovered that if you completely destroy the UITabBarItems and allocate new ones in their place, then those ones will work. :)
So my final solution to this was to add an extra condition in the viewDidLoad method of my controller that if the detected system was iOS 3, and there was already an array of UITabBarItems, it would go through each one, copy out all of the properties needed, destroy it, allocate a new one and then copy the old properties over to the new one.
I'm still going to keep an eye out for a better solution (I think there's a bit of overhead in this method), but thankfully at this stage, iOS 3 legacy support is becoming less and less of an issue. :)