为iPhone 4，iPhone 5及更高版本，iPad加载不同的视图

Question

I currently have the below code that loads the view depending on if the device is and ipad or iphone, however I need to change it to have three different options.

A view for iphone 4, and view for iphone 5 and greater and then view for ipad

if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        self.viewController = [[ViewController alloc] initWithNibName:@"ViewController_iPhone" bundle:nil];
        self.navController= [[UINavigationController alloc] initWithRootViewController:self.viewController];
    } else
    {
        self.viewController = [[ViewController alloc] initWithNibName:@"ViewController_iPad" bundle:nil];
        self.navController= [[UINavigationController alloc] initWithRootViewController:self.viewController];
    }

Answer 1

This is very easy indeed. You can do it, by checking the screen sizes and then deciding what view to show, like so:

if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {

    CGSize result = [[UIScreen mainScreen] bounds].size;
    NSString *viewName;

    if (result.height == 480) {
        // 3.5 inch display - Iphone 4S and below
        viewName = [NSString stringWithFormat:@"ViewController_iPhone_SMALL"];
    }

    else if (result.height == 568) {
        // 4 inch display - iPhone 5
        viewName = [NSString stringWithFormat:@"ViewController_iPhone_5"];
    }

    else if (result.height == 667) {
        // 4.7 inch display - iPhone 6
        viewName = [NSString stringWithFormat:@"ViewController_iPhone_6"];
    }

    else if (result.height == 736) {
        // 5.5 inch display - iPhone 6 Plus
        viewName = [NSString stringWithFormat:@"ViewController_iPhone_6_PLUS"];
    }

    self.viewController = [[ViewController alloc] initWithNibName:viewName bundle:nil];
    self.navController= [[UINavigationController alloc] initWithRootViewController:self.viewController];
} 

else {
        self.viewController = [[ViewController alloc] initWithNibName:@"ViewController_iPad" bundle:nil];
        self.navController= [[UINavigationController alloc] initWithRootViewController:self.viewController];
}