只是为了结合@sickp的答案和下面来自@n13的评论，我把它做成了一个UIScreen类别，这似乎工作得很好。检查在您第一次调用它时完成，然后为以后的调用保存。

@interface UIScreen (RetinaCheck)
+ (BOOL)retinaScreen;
@end

static BOOL isRetinaScreen = NO;
static BOOL didRetinaCheck = NO;

@implementation UIScreen (RetinaCheck)
+ (BOOL)retinaScreen
{
    if (!didRetinaCheck) {
        isRetinaScreen = ([[self mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] &&
                          ([self mainScreen].scale == 2.0));
        didRetinaCheck = YES;
    }
    return isRetinaScreen;
}
@end

可能对某人有用。

比较浮点值是否相等总是让人感觉有点不可靠。 两者我都喜欢

[UIScreen mainScreen].scale > 1.0;

or

[UIScreen mainScreen].scale < 2.0;

这是对Matt MC的回答的重复。只是UIScreen上的一个类别。

#import "UIScreen+Util.h"

@implementation UIScreen (Util)

+ (BOOL) isRetinaDisplay {
    static BOOL retina = NO;
    static BOOL alreadyChecked = NO;
    if (!alreadyChecked) {
        UIScreen *mainScreen = self.mainScreen;
        if (mainScreen) {
            retina = mainScreen.scale > 1.0;
            alreadyChecked = YES;
        }
    }
    return retina;
}

@end

以上答案的Swift版本，>= 2.0规模，因此它包括iPhone 6+和其他未来的高于retina规模的设备:

 if UIScreen.mainScreen().respondsToSelector(Selector("scale")) && UIScreen.mainScreen().scale >= 2.0 {
    // code executed only on Retina device
}

只是为了结合@sickp的答案和下面来自@n13的评论，我把它做成了一个UIScreen类别，这似乎工作得很好。检查在您第一次调用它时完成，然后为以后的调用保存。

@interface UIScreen (RetinaCheck)
+ (BOOL)retinaScreen;
@end

static BOOL isRetinaScreen = NO;
static BOOL didRetinaCheck = NO;

@implementation UIScreen (RetinaCheck)
+ (BOOL)retinaScreen
{
    if (!didRetinaCheck) {
        isRetinaScreen = ([[self mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] &&
                          ([self mainScreen].scale == 2.0));
        didRetinaCheck = YES;
    }
    return isRetinaScreen;
}
@end

可能对某人有用。

试试这个

if ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] &&
    ([UIScreen mainScreen].scale == 2.0))
{
    // Retina display
    NSLog(@"---------------Retina display");
} else {
    // non-Retina display
    NSLog(@"---------------non-Retina display");
}