desert@2x : iPhone 4s (320 x 420)desert-568h@2x : iPhones 5, 5C and 5S (320 x 568)desert-667h@2x : iPhone 6 (375 x 667)desert-736h@3x : iPhone 6+ (414 x 736)desert@2x~ipad : iPad (1024 x 768)

iPhone 4S  Screen Size: 3.5 Inches  Resolution: 640 x 960 (Half: 320 x 480)

iPhone 5  Screen Size: 4.0 Inches  Resolution: 640 × 1136 (Half: 320 x 568)

iPhone 5S/5C  Screen Size: 4.0 Inches  Resolution: 640 x 1136 (Half: 320 x 568)

iPhone 6  Screen Size: 4.7 Inches Resolution: 750 x 1334 (Half: 375 x 667)

iPhone 6 Plus  Screen Size: 5.5 Inches Resolution: 1242 x 2208 (1/3: 414 x 736)  The size of iPhone 6 Plus is @3x scaling. So, it is divided by 3.

#import <UIKit/UIKit.h>typedef NS_ENUM(NSInteger, thisDeviceClass) {    thisDeviceClass_iPhone,    thisDeviceClass_iPhoneRetina,    thisDeviceClass_iPhone5,    thisDeviceClass_iPhone6,    thisDeviceClass_iPhone6plus,    // we can add new devices when we become aware of them    thisDeviceClass_iPad,    thisDeviceClass_iPadRetina,    thisDeviceClass_unknown};thisDeviceClass currentDeviceClass();@interface UIImage (DeviceSpecificMedia)+ (instancetype )imageForDeviceWithName:(NSString *)fileName;@end

#import "UIImage+DeviceSpecificMedia.h"thisDeviceClass currentDeviceClass() {    CGFloat greaterPixelDimension = (CGFloat) fmaxf(((float)[[UIScreen mainScreen]bounds].size.height),                                                    ((float)[[UIScreen mainScreen]bounds].size.width));    switch ((NSInteger)greaterPixelDimension) {        case 480:            return (( [[UIScreen mainScreen]scale] > 1.0) ? thisDeviceClass_iPhoneRetina : thisDeviceClass_iPhone );            break;        case 568:            return thisDeviceClass_iPhone5;            break;        case 667:            return thisDeviceClass_iPhone6;            break;        case 736:            return thisDeviceClass_iPhone6plus;            break;        case 1024:            return (( [[UIScreen mainScreen]scale] > 1.0) ? thisDeviceClass_iPadRetina : thisDeviceClass_iPad );            break;        default:            return thisDeviceClass_unknown;            break;    }}@implementation UIImage (deviceSpecificMedia)+ (NSString *)magicSuffixForDevice{    switch (currentDeviceClass()) {        case thisDeviceClass_iPhone:            return @"";            break;        case thisDeviceClass_iPhoneRetina:            return @"@2x";            break;        case thisDeviceClass_iPhone5:            return @"-568h@2x";            break;        case thisDeviceClass_iPhone6:            return @"-667h@2x"; //or some other arbitrary string..            break;        case thisDeviceClass_iPhone6plus:            return @"-736h@3x";            break;        case thisDeviceClass_iPad:            return @"~ipad";            break;        case thisDeviceClass_iPadRetina:            return @"~ipad@2x";            break;        case thisDeviceClass_unknown:        default:            return @"";            break;    }}+ (instancetype )imageForDeviceWithName:(NSString *)fileName{    UIImage *result = nil;    NSString *nameWithSuffix = [fileName stringByAppendingString:[UIImage magicSuffixForDevice]];    result = [UIImage imageNamed:nameWithSuffix];    if (!result) {        result = [UIImage imageNamed:fileName];    }    return result;}@end

目前ios的指令集有以下幾種：• armv6 ? 
  iPhone? iPhone2? iPhone3G? 第一代和第二代iPod Touch• armv7
? iPhone4? iPhone4S• armv7s 
? iPhone5? iPhone5C• arm64 
? iPhone5S 機器對指令集的支持是向下兼容的，因此armv7的指令集是可以運行在iphone5S的，只是效率沒那么高而已~================================================Architecture ： 指你想支持的指令集。Valid architectures : 指即將編譯的指令集。Build Active Architecture Only : 只是否只編譯當前適用的指令集。================================================ 現(xiàn)在是2014年初，其實4和4S的用戶還是蠻多的，而iphone3之類的機器幾乎沒有了，所以我們的指令集最低必須基于armv7.因此,Architecture的值選擇：armv7 armv7s arm64PS:選arm64時需要最低支持5.1.1:

self.navigationController.navigationBar.barTintColor = [UIColor blackColor];self.navigationController.navigationBar.tintColor = [UIColor whiteColor];[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor whiteColor]}];self.navigationController.navigationBar.translucent = NO;