Objective C message dispatch mechanism

I am just staring to play around with Objective C (writing toy iPhone apps) and I am curious about the underlying mechanism used to dispatch messages. I have a good understanding of how virtual...

How do I disable warnings being flagged as errors in Xcode

Is there a setting Xcode that lets you treat warnings NOT as errors in Xcode? I'm doing a lot of prototyping code where I don't care if I have an unused variable for example. Xcode is treating...

Center content of UIScrollView when smaller

I have a UIImageView inside a UIScrollView which I use for zooming and scrolling. If the image / content of the scroll view is bigger than the scroll view, everything works fine. However, when the...

NSString with \n or line break

Does anyone know how to use line breaks in NSString? I need to do something like this - [NSString stringWithFormat:@"%@,\n%@", mystring1,mystring2];

NSTimer crashes, when I call [Timer isValid] or [Timer invalidate]

I have two NSTimers in my iPhone app. DecreaseTimer works fine, but TimerCountSeconds crashes when I call [timerCountSeconds isValid] or [timerCountSeconds invalidate]. They are used like...

Augmented reality iphone

Is there any sample "augmented reality" app for iPhone or iPod?

iPad SplitView with navigation stack for multiple view controllers

my starting point was this MultipleDetailViews sample code found on xcode. I am trying to create a separate navigation stack for the First- and SecondDetailViewController in order to push new...

Handling NSAsserts in Restkit throws

I am using Restkit's object manager to handle a good chunk of my remote API calls. It throws NSAssert for a wide range of errors. For example, if the server returns a error page as opposed to...

NSPredicate check for kind of object class

I have an array of UIView objects. I want to call - (NSArray *)filteredArrayUsingPredicate:(NSPredicate *)predicate on this array to get array of MyCustomView objects. How to code predicate with...

Appending NSDictionary to other NSDictionary

I have one NSDictionary and it loads up UITableView. If a user scrolls more and more, I call API and pull new data. This data is again in the form of an NSDictionary. Is it possible to add the new...

How to compare two NSArrays for equal content in any order?

I have two NSArrays where the objects of the arrays are the same but might be in different indices. It should print both are equal irrespective of their indices. NSArray *arr1 = [[NSArray...

How to get parameters using symbolic breakpoints in Objective-C

I have a breakpoint that looks like this -[UITableViewCell setSelected:] and it works, but I cannot figure out how to get the value that is being passed in. I have tried -[UITableViewCell...

ESC POS print PNG image

I am very new to ESC POS programming on Objective C. I have tested the printer with normal ESC pos line command and it works perfectly. But I was unable to understand the raster mode command. (GS...

backgroundColor of UIImageView is ignored on iOS7?

Before iOS7, a code like this worked fine on UIImageView's subclass. But not working any more. -(id) initWithFrame:(CGRect) frame{ self = [super initWithFrame:frame]; if(self){ ...

How to handle multiple markers on Google Maps with same location?

I use Google Maps in an app and it is likely that multiple markers are attached to same location where each marker represent a person. In this situation user will not know that there are other...

Custom class not shown in the storyboard identity inspector

I created in my app a new class named EmpresasTableViewController, and in the storyboard I copied CategoriasViewController to EmpresasTableViewController, I just want to assign the class...

Duplicate symbols for architecture x86_64 under Xcode

I now have the same question with above title but have not found the right answer yet. I got the error: ...

How to convert any format(.txt, .Doc) file into epub file in iOS application

I'm developing an app for IOS in which I have to read or write an eBook. In iOS so many libraries are available for reading eBooks, but for writing I didn't find any thing(library or SDK). I have...

How can I view the contents of the App Group Shared Container directory when debugging an iOS app?

Fairly self explanatory. We can view the app's documents, library, tmp directories via Window > Devices (this has been the case forever). But when app extensions came on the scene with iOS8, the...

why UITableViewAutomaticDimension not working?

Hi there is plenty of question answering the dynamic height for UITableViewCell of UITableView. However I find it weird when I did it. here's are some of the answer : here and here usually this...

Xcode keep using old framework version

From the beginning of my project, I use a custom framework, let's call it "custom.framework". But there was a bug in this framework and now I want to use another version of the...

iOS 9: How to change volume programmatically without showing system sound bar popup?

I have to change the volume on iPad and using this code: [[MPMusicPlayerController applicationMusicPlayer] setVolume:0]; But this changing volume and showing system volume bar on iPad. How to...

NSPredicate SELF CONTAINS[c] returns value contained in longer text first

I am using UISearchBar to sort UITableView. Each value in the array which the table is populated with, can have up to 3 words @"Pineapple", @"Pineapple Green", @"Apple Green", @"Apple Green,...

What gets called instead of - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event when Accessibility(voice over is on)

Recently I have put a breakpoint in a UIViews method - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event { } method and checked if the compiler stops here when a user taps on the...

How to make some part of the text label bold in iOS Objective C programmatically?

I have tried like this #define KPrivacyText @"Your privacy is very important to us. We are committed \nto earn your trust by safeguarding your personal \ninformation. All the information you...

Capture redirect url in wkwebview in ios

How do I capture the redirection url in when using WKWebView like if a webpage redirects to another page on submitting the username and password or some other data. I need to capture the...

WKWebView behavior. Reloading after Image picker returns

I am getting a weird behavior of a WKWebview. Resuming the problem is that after the web content ask for a image, the app opens automatically an image picker controller, and after select the...

Xcode project dependencies graph

I am new to Swift/Objective C and Xcode. I am having hard time to understand a project which i have downloaded from GitHub. The project is very big, written in both Objective C and Swift, also...

iOS image picker is not showing images first time even after granting permission

When I fresh install the app and try to add photos even after granting the permission the image picker (I am using QBImagePickerController) can't load any albums or image. But if I terminate the...

How to start audio recording when app running on background?

I am working on audio recording. when application running on foreground i have to start audio recording and going to background at that time audio recording working fine. But my question is that...