Question

I create a new “View-based Application” project and modify the didFinishLaunchingWithOptions: method as follow.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
    // Override point for customization after application launch.
    // Add the view controller's view to the window and display.
    [self.window addSubview:viewController.view];
    [self.window makeKeyAndVisible];
    downloader = [[InternetIOProcess alloc] init]; 
    [downloader initWithServer:[NSURL URLWithString:@"http://www.test.com"] ];
    return YES;
}

InternetIOProcess is a NSObject with two variables, and a method:

@interface InternetIOProcess : NSObject {
    NSMutableArray* downloadingFile;
    NSURL* serverAddress;}
@property (nonatomic,retain) NSMutableArray* downloadingFile;
@property (nonatomic,retain) NSURL* serverAddress;
-(void) initWithServer:(NSURL*) server;

the implementation of InternetIOProcess is:

@implementation InternetIOProcess
@synthesize downloadingFile,serverAddress; //,serviceuploadingQueue,;
-(void) initWithServer:(NSURL*) server
{
    downloadingFile = [NSMutableArray array];
    serverAddress = server;
}

And then, I write a IBAction in UIViewController response to a button “touch up inside” event:

-(IBAction) test:(id)sender
{
    MyAppDelegate* d = (MyAppDelegate*)[UIApplication sharedApplication].delegate;
    InternetIOProcess* thedownloader = d.downloader;
    //value of "thedownloader" incorrect.
}

Try to access “thedownloader” here, its member “downloadingFile, serverAddress” both give random bad values!

Anybody know why can’t I access this object?

Answer 1

The problem lies here with you not retaining the array and the server and bad naming convention of init. It looks like your custom init method is not getting called.

-(void) initWithServer:(NSURL*) server
{
    downloadingFile = [NSMutableArray array];
    serverAddress = server;
}

Try making the following changes

//InternetIOProcess.h add
-(id) initWithServer:(NSURL*) server;

//InternetIOProcess.m change
-(id) initWithServer:(NSURL*) server
{
    self = [super init];
    if(self != nil)
    {
        downloadingFile = [[NSMutableArray array] retain];
        serverAddress = [server retain];
    }
    return self;
}

//MyAppDelegate.m
downloader = [[InternetIOProcess alloc] initWithServer:[NSURL URLWithString:@"http://www.test.com"]];