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POUIView reference returns NULL pointed ARC enabled
 

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  1. POUIView reference returns NULL pointed ARC enabled
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    <p>I have ARC enabled so I am unsure as to why my reference is null.</p> <p>My view controller instantiates a UIView ‘<strong>theGrid</strong>’ as soon as the view is loaded. </p> <p>Later I have switch inside another class (MyOtherClass) that calls the UIViewContoller <code>- (void) updateTheGrid:(id)sender</code> method, that method is called as per the NSLog, but when I output the UIView to see if it is there, its returns null. </p> <p>What am I doing wrong? It was my impression that ARC keeps up with everything. I feel like my trouble is coming from mm "MyOtherClass" when I <code>ViewController * vc = [[ViewController alloc] init];</code> because I feel like that is just creating a new instance. But if that is the case, how am i suppose to reference the old instance and call the method?</p> <p><strong>NSLOG OUTPUT</strong></p> <pre><code>[28853:c07] Intial Grid: &lt;GridView: 0x8e423b0; frame = (0 0; 768 1024); layer = &lt;CALayer: 0x8e43780&gt;&gt; [28853:c07] Update The Grid (null) </code></pre> <p><strong>GridView.h</strong></p> <pre><code>#import &lt;UIKit/UIKit.h&gt; @interface GridView : UIView - (void) gridUpdated; @end </code></pre> <p><strong>GridView.m</strong></p> <pre><code>#import "GridView.h" @implementation GridView - (id)initWithFrame:(CGRect)frame { self = [super initWithFrame:frame]; if (self) { // Initialization code NSLog(@"initWithFrame"); } return self; } - (void)drawRect:(CGRect)rect{ NSLog(@"Grid Draw Rect"); } - (void) gridUpdated { NSLog(@"GRID VIEW.m : Grid update called"); [self setNeedsDisplay]; } @end </code></pre> <p><strong>ViewController.h</strong></p> <pre><code>#import &lt;UIKit/UIKit.h&gt; #import "GridView.h" @interface ViewController : UIViewController { GridView *theGrid; } @property (strong, retain) GridView * theGrid; - (void) updateTheGrid : (id) sender; @end </code></pre> <p><strong>ViewController.m</strong></p> <pre><code>#import "ViewController.h" #import "GridView.h" @interface ViewController () {} @end @implementation ViewController @synthesize theGrid; - (void)viewDidLoad { [super viewDidLoad]; //draw the grid theGrid = [[GridView alloc] initWithFrame:self.view.frame]; NSLog(@"Intial Grid: %@", theGrid); [self.view addSubview:theGrid]; } - (void) updateTheGrid : (id) sender{ NSLog(@"Update The Grid %@", theGrid); [theGrid gridUpdated]; } @end </code></pre> <p><strong>MyOtherClass.m</strong></p> <pre><code>- (void) mySwitch : (id) sender { ViewController * vc = [[ViewController alloc] init]; [vc updateTheGrid:sender]; } </code></pre>
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    1. USJasonBourne
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    1. COwhere is ur updateThePaper method ? what is this means "@property (strong, retain) GridView * theGrid; " ????
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      1. USShamsudheen TK
    2. COSorry I updated the code to edit the typo. It should read updateTheGrid now. As for the '@property (strong, retain) GridView * theGrid;' I was trying different methods of maintain **theGrid** in memory or at least a way to reference it. Do I need that line? @Ramshad
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      1. USJasonBourne
    3. COthe issue is not happening here.. if u don't mind,could u send the sample app to ramshadram90@gmail.com ? I can help u then..
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      1. USShamsudheen TK
 

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