iphone dev: splash screen with tabbar controller + modalviewcontroller

Question

I'm new to iphone app development and I try to build an app with a splash screen. I need the splash screen, because my app needs to load a xml file from the web. during this, the app should show a splash screen (logo + message "loading xml...") and after successful loading it should proceed to the main screen.

I started the app with a tabbar template, because this should be shown after the splash screen. the first tab has a navigation controller (configured in IB) which loads a custom view controller (I called it searchViewController.h/.m/.xib) on his stack.

my problem: if I run my app, the screen keeps for a long time black and then there is very shortly the splash-screen shown (as it moves down/disappearing) and then the tabbar with the other attached views are shown. but while the screen is black, I can see in the console my control NSLog-messages from the XML parsing.

this means: the app starts, fetching XML, parsing XML, showing splash screen for about 1ms and then show the main app. but I want it to show the splash screen already during the XML fetching and parsing.

my AppDelegate.m:

#import "AppDelegate_iPhone.h"
#import "startPage.h"

@implementation AppDelegate_iPhone

@synthesize window;
@synthesize tabBarController;
@synthesize theVendors;
#pragma mark -#pragma mark Application lifecycle

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:
  (NSDictionary *)launchOptions {

        [window addSubview:tabBarController.view];

        //initialise the splash screen from class startPage as loadingPage
        startPage *loadingPage = [[startPage alloc] init];

        //present splash screen as modalview of the tabbar controller            
        [self.tabBarController presentModalViewController:loadingPage animated:NO];

        //make the hole thing visible (should be visible, but isn't (that's the problem))
        [self.window makeKeyAndVisible];

        //call the splash-screen controller for doing the XML work
        [loadingPage initVendors];
        [loadingPage release];

        return YES;
}

and now the spash-screen method for the XML stuff:

-(void)initVendors{
    vendors *theVendorsLocal = [[vendors alloc] initWithDictionary];
    NSURL *xmlURL = [NSURL URLWithString:@"http://.../muuhh.xml"];

    fParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];
    [fParser setDelegate:theVendorsLocal];
    [fParser setShouldProcessNamespaces:NO];
    [fParser setShouldReportNamespacePrefixes:NO];
    [fParser setShouldResolveExternalEntities:NO];
    [fParser parse];
    [xmlURL release];



if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad){
    //AppDelegate_iPad *del = (AppDelegate_iPad *)[UIApplication sharedApplication].delegate;   
    //del.theVendors = theVendorsLocal;
}else{
    AppDelegate_iPhone *del = (AppDelegate_iPhone *)[UIApplication sharedApplication].delegate;     
    del.theVendors = theVendorsLocal;
}

    //detach the modalview from the tabbar controller
[self.parentViewController dismissModalViewControllerAnimated:YES];
}

so the problem is, that the whole parsing stuff is done BEFORE the splash screnn is shown.

why??

as you can see, I load the tabbarcontroller.view, put it as subview of window, set the modalview and do the [self.window makeKeyAndVisible] before I call the [loadingPage initVendors]; method...

why is the splash screen shown after the whole parsing stuff (actually it's not even shown, I just see how it slides out)??

thanks for any help...

I tried to move the [self.window makeKeyAndVisible] to the very top, but the results are still the same:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    breakpoint1 ->  [self.window makeKeyAndVisible];
    breakpoint2 ->  [window addSubview:tabBarController.view];

    //initialise the splash screen from class startPage as loadingPage
    breakpoint3 ->  startPage *loadingPage = [[startPage alloc] init];

    //present splash screen as modalview of the tabbar controller            
    [self.tabBarController presentModalViewController:loadingPage animated:NO];

...

I also tried around with other arrangements, nothing worked. finally I started setting breakpoints and using NSLog to show me, how the app is calling every method. while observing the screen, I found out, that the method-call of [self.window makeKeyAndVisible] doesn't show the view directly after the call..

I marked the breakpoints in the source code above: I would have assumed, that after breakpoint1 the black screen would disappear and a white screen is shown (the window) and afterwards at breakpoint2 the tabbar is shown (at least at breakpoint3). but nothing happens. the screen remains black until the whole idFinishLaunchingWithOptions-method is finished.

I also placed some breakpoints in the applicationDidBecomeActive-method, which is called after the didFinishLaunchingWithOptions-method. if the debugger breaks in one breakpoint in the applicationDidBecomeActive-method, even then there is nothing shown on the screen, the screnn still remains black.

finally after leaving the applicationDidBecomeActive-method the tabbar is shown.

I have no clou, where the app "goes" after leaving the applicationDidBecomeActive-method.

And I would like to know, where and when the tabbar is actually shown?

why does [self.window makeKeyAndVisible] doesn't show the window if I stop at a b reakpoint directly behind this call?

Toastor Toastor · Accepted Answer · 2011-02-16T18:44:15

I suspect the tabbarcontroller is unable to present your splashscreen modally in time, because at that point your window is still invisible, hence hiding the view hierarchy attached to it. The splashscreen belongs to this hierarchy too.

Try moving the "makeKeyAndVisible" method to the beginning of your didFinishLaunchingMethod, otherwise making the view hierarchy is visible until after parsing your xml is complete - just as you are observing it.

iphone dev: splash screen with tabbar controller + modalviewcontroller

1 Answers