IOS 判断设备屏幕尺寸、分辨率

根据屏幕尺寸和分辨率，ios现在数起来有6个版本。

iOS 设备现有的分辨率如下：
iPhone/iPod Touch
普通屏                         　 320像素 x 480像素       iPhone 、3G、3GS，iPod Touch 、、
： Retina 屏           　　640像素 x 960像素        iPhone 、4S，iPod Touch
： Retina 屏               640像素 x 1136像素      iPhone ，iPod Touch 

iPad
普通屏         　　　　　　   768像素 x 1024像素      iPad ， iPad2，iPad mini
Retina屏     　　　　         1536像素 x 2048像素     New iPad，iPad 

UIDevice+Resolutions.h

//
//  UIDevice+Resolutions.h
//  Test_common
//
//  Created by wangzhipeng on 13-1-30.
//  Copyright (c) 2013年 com.comsoft. All rights reserved.
//

#import 

enum {
    // iPhone 1,3,3GS 标准分辨率(320x480px)
    UIDevice_iPhoneStandardRes      = ,
    // iPhone 4,4S 高清分辨率(640x960px)
    UIDevice_iPhoneHiRes            = ,
    // iPhone 5 高清分辨率(640x1136px)
    UIDevice_iPhoneTallerHiRes      = ,
    // iPad 1,2 标准分辨率(1024x768px)
    UIDevice_iPadStandardRes        = ,
    // iPad 3 High Resolution(2048x1536px)
    UIDevice_iPadHiRes              =
}; typedef NSUInteger UIDeviceResolution;

@interface UIDevice (Resolutions){

}

+ (UIDeviceResolution) currentResolution;

+ (BOOL)isRunningOniPhone5;

+ (BOOL)isRunningOniPhone;

@end

UIDevice+Resolutions.m

//
//  UIDevice+Resolutions.m
//  Test_common
//
//  Created by wangzhipeng on 13-1-30.
//  Copyright (c) 2013年 com.comsoft. All rights reserved.
//

#import "UIDevice+Resolutions.h"

@implementation UIDevice (Resolutions)

+ (UIDeviceResolution) currentResolution {
    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone){
        if ([[UIScreen mainScreen] respondsToSelector: @selector(scale)]) {
            CGSize result = [[UIScreen mainScreen] bounds].size;
            result = CGSizeMake(result.width * [UIScreen mainScreen].scale, result.height * [UIScreen mainScreen].scale);
            if (result.height <= 480.0f)
                return UIDevice_iPhoneStandardRes;
            return (result.height >  ? UIDevice_iPhoneTallerHiRes : UIDevice_iPhoneHiRes);
        } else
            return UIDevice_iPhoneStandardRes;
    } else
        return (([[UIScreen mainScreen] respondsToSelector: @selector(scale)]) ? UIDevice_iPadHiRes : UIDevice_iPadStandardRes);
}

+ (BOOL)isRunningOniPhone5{
    if ([self currentResolution] == UIDevice_iPhoneTallerHiRes) {
        return YES;
    }
    return NO;
}

+ (BOOL)isRunningOniPhone{
    return (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone);
}

@end