问题

I am trying to build a game for the iphone using cocos2d engine. I wanted to know how can I tell a difference whether the user is using iphone 4 or iphone 3 as I wanted to load hi-resolution graphics for the iphone4 and low-resolution for iphone 3. I know if I use @2x.png at the end of the image file name UIImage loads the hi-resolution image by itself if I am using an iphone 4 but for the game I am using cocos2d engine\'s CCSprite class to load the graphics.

I would really appreciate the reply.

Regards, Ankur

回答1:

You could check the scale of the screen.

if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] && [[UIScreen mainScreen] scale] == 2){
    //iPhone 4
}

回答2:

For detecting retina display on all devices including the new iPad

    +(BOOL)isRetinaDisplay {
    // since we call this alot, cache it
    static CGFloat scale = 0.0;
    if (scale == 0.0) {
        // NOTE: In order to detect the Retina display reliably on all iOS devices,
        // you need to check if the device is running iOS4+ and if the 
        // [UIScreen mainScreen].scale property is equal to 2.0. 
        // You CANNOT assume a device is running iOS4+ if the scale property exists,
        // as the iPad 3.2 also contains this property.
        // On an iPad running iOS3.2, scale will return 1.0 in 1x mode, and 2.0
        // in 2x mode -- even though we know that device does not contain a Retina display.
        // Apple changed this behavior in iOS4.2 for the iPad: it returns 1.0 in both
        // 1x and 2x modes. You can test this yourself in the simulator.
        // I test for the -displayLinkWithTarget:selector: method on the main screen
        // which exists in iOS4.x but not iOS3.2, and then check the screen's scale:

        if ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] && 
            ([UIScreen mainScreen].scale == 2.0)) {
            scale = 2.0;
            return YES;
        } else {
            scale = 1.0;
            return NO;
        }   

    }
    return scale > 1.0;
}

Credit to: Adriano Paladini http://developer.appcelerator.com/question/133826/detecting-new-ipad-3-dpi-and-retina

回答3:

- (NSString *) platform  
{  
    size_t size;  
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);  
    char *machine = malloc(size);  
    sysctlbyname("hw.machine", machine, &size, NULL, 0);  
    NSString *platform = [NSString stringWithCString:machine];  
    free(machine);  
    return platform;  
}  

- (NSString *) platformString  
{  
    NSString *platform = [self platform];  
    if ([platform isEqualToString:@"iPhone1,1"]) return @"Original iPhone";  
    if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";  
    if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3G[S]"; 
    if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";   
    return @"Unknown";  
}

回答4:

Despite what Apple's docs say, the UIScreen's scale property isn't just available in iOS4, it's also available in 3.2 on the iPad. This means it's probably an unreliable way to check which device you're on.

Instead, you should check if contentScaleFactor is available on your main window(or any UIView), and then check the scale value.

回答5:

Checking the scale property is not sufficient, as on iPad 3.2 in 2x mode, the scale property exists and will return 2.0, but we know that device does NOT have a Retina display.

I've created at category on UIScreen to do this. For a more detailed explanation, see my answer to Detect Retina Display. Here's the code:

@interface UIScreen(ZBScreenRetinaAdditions)

// Returns YES if this is a Retina display.
- (BOOL)zb_isRetina;

@end

@implementation UIScreen(ZBScreenRetinaAdditions)

- (BOOL)zb_isRetina {
  return [self respondsToSelector:@selector(displayLinkWithTarget:selector:)] && (self.scale == 2.0);
}

@end

Usage example:

if ([UIScreen mainScreen] zb_isRetina) {
  // Retina display
}

回答6:

just adding my 2 cents :

I see what you are doing here, but binding this to a specific value like 2.0 is good for the moment, but what if for example next iPad got resolution bump like x1.5 ? For me anything that goes above 1.0 is kind of higher-than-normal display so I will load hi-res graphics. Does not matter much then if that is iPad,iPhone ....

回答7:

I know that the topic is a bit old now, but It might help some people. On Cocos2d you can load hi-resolution graphics for the iphone4 and low-resolution for iphone 3 using the -hd suffix on your files.

You just have to enable the retina display like this before:

// Enables High Res mode (Retina Display) on iPhone 4 and maintains low res on all other devices
if( ! [director enableRetinaDisplay:YES] )
    CCLOG(@"Retina Display Not supported");

For more information read the documentation here: RetinaDisplay in cocos2d

回答8:

import "UIScreen+Retina.h"

if([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad){
    //IPAD        
    if ([[UIScreen mainScreen] isRetina]) {
        // IPAD 3 - Retina display
        bannersGetPromoServerRequest.size = kXML_API_IMAGESIZE_IPAD_HIGHRES;            
    }else{
        //iPAD 1/2
        bannersGetPromoServerRequest.size = kXML_API_IMAGESIZE_IPAD_LOWRES;        }
}else{
    //IPHONE
    if ([[UIScreen mainScreen] isRetina]) {
        // IPHONE 4/4s/5 - Retina display
        bannersGetPromoServerRequest.size = kXML_API_IMAGESIZE_IPHONE_HIGHRES;

    }else{
        //IPHONE (3.x)
        bannersGetPromoServerRequest.size = kXML_API_IMAGESIZE_IPHONE_LOWRES;

    }
}

回答9:

scale is available for iPad, however you can always use if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) to check whether it is iPad or iPhone/iTouch

来源：https://stackoverflow.com/questions/3294100/how-to-differentiate-between-iphone4-and-iphone-3

标签

ios

ccsprite

How to differentiate between iphone4 and iphone 3

问题