It&#39;s a replacement for the `retain` attribute, as part of [Objective-C Automated Reference Counting (ARC)](http://clang.llvm.org/docs/AutomaticReferenceCounting.html). In non-ARC code it&#39;s just a synonym for `retain`.

A strong reference is a reference to an object that stops it from being deallocated. In other words it creates a owner relationship. Whereas previously you would do this:
    	
    **// Non-ARC Compliant Declaration
    @property(retain) NSObject *obj;**
    
Under ARC we do the following to ensure a class instance takes an ownership interest a referenced object (i.e. so it cannot be deallocated until the owner is).
    	
    **// ARC Compliant Declaration
    @property(strong) NSObject *obj;**

As we know, we cannot release any object in an ARC-based project in iOS 5.
So when we want to retain any object for further use at a later stage and don&#39;t want ARC to remove the object from memory, then we set the property for the object as &quot;Strong&quot;.

I am trying with Gradle first time. I am trying with a maven java project to compile and create a jar file. It is compiling and creating the jar file in build/libs directory as 

&gt; **trunk**-XXXVERSION-SNAPSHOT.jar

I am running gradle build file from trunk directory of this maven java project. 

I want to get the project name (for ex: project1) in the jar file name, something like 

&gt; **project1**-XXXVERSION-SNAPSHOT.jar

 in build/libs directory.
Please suggest.


Gradle - jar file name in java plugin

My class should extend two classes at the same time:

    public class Preferences extends AbstractBillingActivity {
    
    public class Preferences extends PreferenceActivity {

How to do so?


**Upd**. Since this is not possible, how should I use that [AbstractBillingActivity][1] with Preferences then?

**Upd2**. If I go with interfaces, should I create:

 1. BillingInterface
    
        public interface BillingInterface extends PreferenceActivity, AbstractBillingActivity {
        
        }
    
 2. PreferenceActivity
    
        public interface PreferenceActivity {
        
        }
    
 3. AbstractBillingActivity
    
        public interface AbstractBillingActivity {
            
            	void onCreate(Bundle savedInstanceState);
            
        }

and then 

    public class Preferences implements BillingInterface {

  [1]: http://github.com/robotmedia/AndroidBillingLibrary






Can one class extend two classes?

I am using the Xcode beta for developers, and am noticing some subtle differences. Among them is a new attribute for declared properties.

    @property(strong)IBOutlet NSArrayController *arrayControl;

My question is: what does the strong attribute mean?? Does it replace some older one, or is it something entirely new? I have searched through google and the developer documentation and havent been able to find anything. Until i know what it is i am hesitant to use it.

Thanks in advance

What is the strong property attribute

I am using the Xcode beta for developers, and am noticing some subtle differences. Among them is a new attribute for declared properties.
<pre><code class="hljs language-objectivec">@property(strong)IBOutlet NSArrayController *arrayControl;
</code></pre>
My question is: what does the strong attribute mean?? Does it replace some older one, or is it something entirely new? I have searched through google and the developer documentation and havent been able to find anything. Until i know what it is i am hesitant to use it.
Thanks in advance

I&#39;m setting text color for `UIButton`


    headingButton.titleLabel.textColor = [UIColor colorWithRed:36/255.0 
                                                         green:71/255.0 
                                                          blue:113/255.0 
                                                         alpha:1.0];


It&#39;s not changing color same code I&#39;m using in another code it&#39;s working.

UIButton title text color

I&#39;m implementing a color-chooser table view where the user can select amongst, say, 10 colors (depends on the product). The user can also select other options (like hard drive capacity, ...).

All color options are inside their own tableview section.

I want to display a little square on the left of the textLabel showing the actual color.

Right now I&#39;m adding a simple square UIView, give it the correct background color, like this :


	- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
		UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:RMProductAttributesCellID];
		if (cell == nil) {
			cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:RMProductAttributesCellID] autorelease];
			cell.indentationWidth = 44 - 8;
			
			UIView *colorThumb = [[[UIView alloc] initWithFrame:CGRectMake(8, 8, 28, 28)] autorelease];
			colorThumb.tag = RMProductAttributesCellColorThumbTag;
			colorThumb.hidden = YES;
			[cell.contentView addSubview:colorThumb];
		}
		
		RMProductAttribute *attr = (RMProductAttribute *)[_product.attributes objectAtIndex:indexPath.section];
		RMProductAttributeValue *value = (RMProductAttributeValue *)[attr.values objectAtIndex:indexPath.row];
		cell.textLabel.text = value.name;
		cell.textLabel.backgroundColor = [UIColor clearColor];
		
		UIView *colorThumb = [cell viewWithTag:RMProductAttributesCellColorThumbTag];
		colorThumb.hidden = !attr.isColor;
		cell.indentationLevel = (attr.isColor ? 1 : 0);
		
		if (attr.isColor) {
			colorThumb.layer.cornerRadius = 6.0;
			colorThumb.backgroundColor = value.color;
		}
		
		[self updateCell:cell atIndexPath:indexPath];
		
		return cell;
	}


This displays fine without problems.

My only problem is that when I select a &quot;color&quot; row, during the fade-to-blue selection animation, my custom UIView (colorThumb) is hidden. It gets visible again just after the selection/deselection animation ended, but this produces an ugly artifact.

What should I do to correct this? Don&#39;t I insert the subview at the right place?

(There&#39;s nothing special in the didSelectRowAtIndexPath, I just change the cell&#39;s accessory to a checkbox or nothing, and deselect the current indexPath).

UITableViewCell subview disappears when cell is selected

I had a Macintosh I used to develop iPhone apps with using Xcode 4.
I now have a new Macintosh with a new install of... everything.

When opening Xcode projects built on the old Mac, I cannot run the app on the iPhone that was configured as a development iPhone.  
Xcode 4 organizer tells me &quot;Valid signing identity not found&quot; on my provisioning profiles.

I guess this is something to do with the .certSigningRequest file I had generated before on the old Mac (I have a backup of that file), but what do I have to do with it on the new Mac?

Another strange thing, I don&#39;t see my 5 existing provisioning profiles (defined on Apple provisioning portal) in the organizer, even after a refresh and after having entered my provisioning portal login and password :

[![organizer devices screenshot][1]][1]


  [1]: http://i.stack.imgur.com/iz9AM.png

Xcode 4 - &quot;Valid signing identity not found&quot; error on provisioning profiles on a new Macintosh install

My project worked perfectly on simulator+device,  
but now, after upgrading to **lion** os and **xcode 4.1**, I get this error when gps is active!

    server did not accept client registration 68

It&#39;s a gps based application, and i&#39;m nervous to not debug app in simulator!

Any idea to solve this issue?


----------


**UPDATE**: Gps on Simulator doesn&#39;t work also on Xcode 3.2.6 + LION.


----------

**EDIT**: Apple response on bug tracker:  

&gt; After further investigation it has
&gt; been determined that this is a known issue, which is currently being
&gt; investigated by engineering. This issue has been filed in our bug
&gt; database under the original Bug ID#.   Thank you for submitting this
&gt; bug report. We truly appreciate your assistance in helping us discover
&gt; and isolate bugs.



How to solve Xcode 4.1 (LION) GPS error?

I am just wondering how you repeat a AVAudioPlayer?


How do I repeat a AVAudioPlayer?

I have been googling so much on how to do this, but how would I reverse a NSString? Ex:hi would become: ih

I am looking for the easiest way to do this.

Thanks!

@Vince I made this method:

    - (IBAction)doneKeyboard {
    
    // first retrieve the text of textField1
    NSString *myString = field1.text;
    NSMutableString *reversedString = [NSMutableString string];
    NSUInteger charIndex = 0;
    while(myString &amp;&amp; charIndex &lt; [myString length]) {
        NSRange subStrRange = NSMakeRange(charIndex, 1);
        [reversedString appendString:[myString substringWithRange:subStrRange]];
        charIndex++;
    }
    // reversedString is reversed, or empty if myString was nil
    field2.text = reversedString;
    }

I hooked up that method to textfield1&#39;s didendonexit. When I click the done button, it doesn&#39;t reverse the text, the UILabel just shows the UITextField&#39;s text that I entered. What is wrong?


Reverse NSString text

What unit of time does timeIntervalSinceDate return? Is it seconds, milliseconds or something else?

The documentation says that it returns an NSTimeInterval, but what *unit of time* is that value?

What unit of time does timeIntervalSinceDate return?

I use the NSUserDefaults dictionary to store basic information such as high scores etc so that when the user closes the app data is not lost. Anyways I use:

    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

to store data. If I wish to store a new high score for example then I would do:

    [prefs setInteger:1023 forKey:@&quot;highScore&quot;];
    [prefs synchronize];  //this is needed in case the app is closed. 

and later if I wish to retrieve the high score I would do:

    [prefs integerForKey:@&quot;highScore&quot;];


anyways the point is that I store a lot of other things because the `NSUserDefaults enable` you to store `booleans`, `integers`, `objects` etc.   what method would I have to execute to delete all keys so that NSUserDefaults becomes like the fist time I launch the app?

I am looking for something like:

    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    [prefs deleteAllKeysAndObjectsInTheDictionary];

or maybe there is a way of getting all keys and I have to loop through each object but I don&#39;t know how to remove them. 


EDIT:


I have tried :

    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    [NSUserDefaults resetStandardUserDefaults];
    [prefs synchronize];

and I still am able to retrieve a high score....



Delete all keys from a NSUserDefaults dictionary iOS

How can I add text alignment attribute to an NSAttributedString to center the text?

Edit:
Am I doing anything wrong? It doesn&#39;t seem to change the alignment.

	CTParagraphStyleSetting setting;
	setting.spec = kCTParagraphStyleSpecifierAlignment;
	setting.valueSize = kCTCenterTextAlignment;
	
	CTParagraphStyleSetting settings[1] = {
		{kCTParagraphStyleSpecifierAlignment, sizeof(CGFloat), &amp;setting},			
	};
	
	CTParagraphStyleRef paragraph = CTParagraphStyleCreate(settings, sizeof(setting));
	
	NSMutableAttributedString *mutableAttributed = [[NSMutableAttributedString alloc] initWithAttributedString:self.attributedString];
	[mutableAttributed addAttributes:[NSDictionary dictionaryWithObjectsAndKeys:(NSObject*)paragraph ,(NSString*) kCTParagraphStyleAttributeName, nil] range:_selectedRange];

NSAttributedString add text alignment

I&#39;m trying to create a nib that contains a view that will be embedded in a TableViewCell. I&#39;ve created the interface and implementation files, `ResultCell.h` and `ResultCell.m`. They&#39;re stock, out-of-the-box, no code changes.

I then create an empty XIB file, and drag a UIView onto it. Then I click File&#39;s Owner, and set the type to `ResultCell`. I click the view, and set its class to also be `ResultCell`.

Here are the problems I have:

1. When using the Assistant Editor view (which I live in), the `ResultCell.h` file doesn&#39;t appear when I&#39;m viewing the ResultCell.xib file. I have to force it to load by clicking on Automatic and selecting the file.
2. When I drop a label in the view, and then Ctrl+Click and drag to the .h to create an outlet, I get this error message: &quot;**Could not insert new outlet connection:** Could not find any information about the class named ResultCell.&quot;

I&#39;ve tried creating and re-creating the view, and it&#39;s just not working, and I&#39;ve started to lose my patience. Any help would be very, very appreciated!

Xcode 4: Creating a UIView xib, not properly connecting

Hello&lt;br/&gt;this weekend I started to watch the 2011 WWDC videos. I&#39;ve found really interesting topics about iOS. My favorites were about performance and graphics, but I&#39;ve found two of them apparently in contradiction. Of course there is something that I didn&#39;t get.
The sessions that I&#39;m talking about are Understanding UIKit Rendering -121 and Polishing your app -105.
&lt;br/&gt;
Unfortunately sample code from 2011 is still not downloadable, so is pretty hard to have an overall view.
In one session they explain that most of times offscreen rendering should be avoided during visualization in scrollview etc. They fix the performance issues in the sample code almost drawing everything inside the -drawRect method.
In the other session the performance issue (on a table view) seems to be due to too much code in the -drawRect method of the table&#39;s cells.&lt;br/&gt;
First is not clear to me when an OffScreen rendering is required by the system, I&#39;ve seen in the video that some quartz function such as: cornerRadious, shadowOffset, shadowColor requires it, but does exist a general rule?&lt;br/&gt;
Second I don&#39;t know if I understood well, but it seems that when there is no offscreen rendering adding layers or views is the way to go.
I hope someone could bring light about that..&lt;br/&gt;
Thanks,&lt;br/&gt;
Andrea


When does a view (or layer) require offscreen rendering?

I&#39;m writing StoreKit-related code, and I&#39;m getting some rather troubling error codes when I try to add a purchase to the queue.

So far, I&#39;ve experienced error codes -1003 and -1004 and I can&#39;t find anything about those codes on the internet.

Running a product request returns valid product numbers, so I don&#39;t know why calls to `[[SKPaymentQueue defaultQueue] addPayment:aPayment];` would fail with this undocumented problem.

The same code also works without the errors on one device but not on another.

The questions I have are, as of yet, unanswered:

What do these codes mean?
How can I mitigate this problem?
Why are they happening for purchase attempts and not for product requests?

Troubleshooting I&#39;ve done includes regenerating a signing certificate and provisioning profile, changing WiFi networks, cleaning and building and reinstalling all related software and components, and none of these things individually or together have helped fix the problem.

EDIT:

Found a discussion about this on the Apple dev forums, but no one from Apple has responded: https://devforums.apple.com/thread/107121?tstart=75 (iOS developer account required to view)

EDIT:

I was hit with error code -1001 today, to add to this list of inexplicable and intermittent problems.  Still no accountability from Apple, that I can find.

EDIT:

I have a suspicion that these error codes are randomly generated and really only indicate that the Sandbox is down.  Anyone else experience this problem?

Undocumented NSURLErrorDomain error codes (-1001, -1003 and -1004) using StoreKit

I&#39;m trying to get the file path of a file called &quot;temp.pdf&quot; which is located in the NSTemporaryDirectory folder (I&#39;ve checked, the file exists).

I use this:

    NSString *filePath = [[NSBundle mainBundle] pathForResource:@&quot;temp&quot; ofType:@&quot;pdf&quot; inDirectory:NSTemporaryDirectory()];

I&#39;ve tried with:

    NSString *filePath = [[NSBundle mainBundle] pathForResource:@&quot;temp.pdf&quot; ofType:@&quot;&quot; inDirectory:NSTemporaryDirectory()];

And:

    NSString *filePath = [[NSBundle mainBundle] pathForResource:@&quot;temp&quot; ofType:@&quot;pdf&quot;];

But it seems that it doesn&#39;t work, return value is always null.

How can I access the file path?

Get file path and URL for file in temp directory

In ARC enabled code, how to fix a warning about a potential retain cycle, when using a block-based API?

The warning:  
`Capturing &#39;request&#39; strongly in this block is likely to lead to a retain cycle`

produced by this snippet of code:  
    
    ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:...

	[request setCompletionBlock:^{
	    NSDictionary *jsonDictionary = [[CJSONDeserializer deserializer] deserialize:request.rawResponseData error:nil];
        // ...
	    }];

Warning is linked to the use of the object `request` inside the block.

Fix warning &quot;Capturing [an object] strongly in this block is likely to lead to a retain cycle&quot; in ARC-enabled code

I want to distribute Framework A. Framework A depends on Framework B. I want a user of my framework to only need to include Framework A, but still have programmatic access to Framework B.

Apple does this all the time using the concept of &quot;Umbrella Frameworks&quot;, but there is this topic in the docs:

&gt; **Don&#39;t Create Umbrella Frameworks**
&gt; 
&gt; While it is possible to create umbrella frameworks using Xcode, doing
&gt; so is unnecessary for most developers and is not recommended. Apple
&gt; uses umbrella frameworks to mask some of the interdependencies between
&gt; libraries in the operating system. In nearly all cases, you should be
&gt; able to include your code in a single, standard framework bundle.
&gt; Alternatively, if your code was sufficiently modular, you could create
&gt; multiple frameworks, but in that case, the dependencies between
&gt; modules would be minimal or nonexistent and should not warrant the
&gt; creation of an umbrella for them.

Why is this approach discouraged? What makes it a good solution for Apple&#39;s problem of interdependent frameworks but not for mine?

Why are umbrella frameworks discouraged?

On my Lion app, I have this data model:

![enter image description here][1]

The relationship `subitems` inside `Item` **is ordered**.
 
Xcode 4.1 (build 4B110) has created for me the file `Item.h`, `Item.m`, `SubItem.h` and `SubItem.h`.
 
Here is the content (autogenerated) of `Item.h`:

    #import &lt;Foundation/Foundation.h&gt;
    
    #import &lt;CoreData/CoreData.h&gt;
    
    @class SubItem;
    
    @interface Item : NSManagedObject {
    @private
    }
    
    @property (nonatomic, retain) NSString * name;
    @property (nonatomic, retain) NSOrderedSet *subitems;
    @end
    
    @interface Item (CoreDataGeneratedAccessors)
    
    - (void)insertObject:(SubItem *)value inSubitemsAtIndex:(NSUInteger)idx;
    - (void)removeObjectFromSubitemsAtIndex:(NSUInteger)idx;
    - (void)insertSubitems:(NSArray *)value atIndexes:(NSIndexSet *)indexes;
    - (void)removeSubitemsAtIndexes:(NSIndexSet *)indexes;
    - (void)replaceObjectInSubitemsAtIndex:(NSUInteger)idx withObject:(SubItem *)value;
    - (void)replaceSubitemsAtIndexes:(NSIndexSet *)indexes withSubitems:(NSArray *)values;
    - (void)addSubitemsObject:(SubItem *)value;
    - (void)removeSubitemsObject:(SubItem *)value;
    - (void)addSubitems:(NSOrderedSet *)values;
    - (void)removeSubitems:(NSOrderedSet *)values;
    
    @end

And here is the content (autogenerated) of `Item.m`:

    #import &quot;Item.h&quot;
    #import &quot;SubItem.h&quot;
    
    @implementation Item
    
    @dynamic name;
    @dynamic subitems;
    
    @end
 
As you can see, the class `Item` offers a method called `addSubitemsObject:`. Unfortunately, when trying to use it in this way:

    Item *item = [NSEntityDescription insertNewObjectForEntityForName:@&quot;Item&quot; inManagedObjectContext:self.managedObjectContext];
    item.name = @&quot;FirstItem&quot;;
    
    SubItem *subItem = [NSEntityDescription insertNewObjectForEntityForName:@&quot;SubItem&quot; inManagedObjectContext:self.managedObjectContext];
    
    [item addSubitemsObject:subItem];

this error appear:

    2011-09-12 10:28:45.236 Test[2002:707] *** -[NSSet intersectsSet:]: set argument is not an NSSet

Can you help me?

**Update:**

After just 1,787 days from my bug report, today (August 1, 2016) Apple wrote me this: *&quot;Please verify this issue with the latest iOS 10 beta build and update your bug report at bugreport.apple.com with your results.&quot;*. Let&#39;s hope this is the right time :)

  [1]: http://i.stack.imgur.com/CYI00.png

Exception thrown in NSOrderedSet generated accessors

I am trying to access a `model.filefield` in Django to parse a [CSV][1] file in Python using the `csv` module. It&#39;s working on Windows, but on Mac it gave me this:

    Exception Type: Error

    Exception Value: new-line character seen in unquoted field - do you need to open the file in universal-newline mode?

This is the code:

    myfile = customerbulk.objects.all()[0].fileup

    mydata = csv.reader(myfile)
        for email,mobile,name,civilid in mydata:
            print email,mobile,name,civilid

  [1]: http://en.wikipedia.org/wiki/Comma-separated_values


Open the file in universal-newline mode using the CSV Django module

I am going to set the path for mySQl on my computer (I&#39;m running Snow Leopard) but I see different instructions online.

Some say to change the .profile file and some say to change the .bash_profile file. What is the difference?

Difference between .profile and .bash_profile on Snow Leopard

Just upgraded my computer to Mac OS X Lion and went to terminal and typed &quot;make&quot; but it says:
-bash: make: command not found

Where did the &quot;make&quot; command go?



Where can I find &quot;make&quot; program for Mac OS X Lion?

I recently upgraded to OSX 10.7, at which point my rails installation completely borked when trying to connect to the psql server.   When I do it from the command line using 

    psql -U postgres

it works totally fine, but when I try to run the rails server or console with the same username and password, I get this error 

    ...activerecord-3.0.9/lib/active_record/connection_adapters/postgresql_adapter.rb:950:in `initialize&#39;: could not connect to server: Permission denied (PGError)	
    Is the server running locally and accepting
    	connections on Unix domain socket &quot;/var/pgsql_socket/.s.PGSQL.5432&quot;?

Any ideas what might be going on would be super helpful!  Thanks!

Repairing Postgresql after upgrading to OSX 10.7 Lion

I need to retrieve the default gateway on a Mac machine. I know that in Linux route -n will give an output from which I can easily retrieve this information. However this is not working in Mac OSX(Snow Leopard). 

I also tried `netstat -nr | grep &#39;default&#39;`, but I was hoping for a cleaner output like that produced by `route -n` in Linux/Unix. `netstat -nr` lists all the interfaces and the default gateway for them.

Any kind of suggestion or a hint in the right direction will be appreciated.

Content Type	Original Author	Original Content on Stackoverflow
Question	Chance Hudson	View Question on Stackoverflow
Solution 1 - Iphone	Lily Ballard	View Answer on Stackoverflow
Solution 2 - Iphone	Jack Farnandish	View Answer on Stackoverflow
Solution 3 - Iphone	sanjeev sharma	View Answer on Stackoverflow

What is the strong property attribute

Iphone Problem Overview

Iphone Solutions

Solution 1 - Iphone

Solution 2 - Iphone

Solution 3 - Iphone

Can one class extend two classes?

Gradle - jar file name in java plugin

Attributions