iOS SDK是否提供了一种简单的方法来检查currentDevice是否具有高分辨率的显示器(retina) ?
我现在发现的最好的方法是:
if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] == YES && [[UIScreen mainScreen] scale] == 2.00) {
// RETINA DISPLAY
}
iOS SDK是否提供了一种简单的方法来检查currentDevice是否具有高分辨率的显示器(retina) ?
我现在发现的最好的方法是:
if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] == YES && [[UIScreen mainScreen] scale] == 2.00) {
// RETINA DISPLAY
}
当前回答
// .h
UIKIT_EXTERN bool isRetinaDisplay();
// .m
bool isRetinaDisplay()
{
static bool flag;
#ifdef __BLOCKS__
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
if([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
{
flag = [[UIScreen mainScreen] scale] > 1.0;
}
else
{
flag = false;
}
});
#else
static bool onceToken;
if(onceToken == false)
{
onceToken = true;
if([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
{
flag = [[UIScreen mainScreen] scale] > 1.0;
}
else
{
flag = false;
}
}
#endif
return flag;
}
其他回答
SSToolkit有一个这样做的方法:
http://sstoolk.it/documentation/Categories/UIScreen (SSToolkitAdditions) . html
它的用法如下:
[[UIScreen mainScreen] isRetinaDisplay];
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
这是一个方便的快速扩展:
Swift v5更新:
extension UIScreen {
public var isRetina: Bool {
guard let scale = screenScale else {
return false
}
return scale >= 2.0
}
public var isRetinaHD: Bool {
guard let scale = screenScale else {
return false
}
return scale >= 3.0
}
private var screenScale: CGFloat? {
guard UIScreen.main.responds(to: #selector(getter: scale)) else {
return nil
}
return UIScreen.main.scale
}
}
用法:
if UIScreen.main.isRetina {
// Your code
}
原:
extension UIScreen {
public func isRetina() -> Bool {
return screenScale() >= 2.0
}
public func isRetinaHD() -> Bool {
return screenScale() >= 3.0
}
private func screenScale() -> CGFloat? {
if UIScreen.mainScreen().respondsToSelector(Selector("scale")) {
return UIScreen.mainScreen().scale
}
return nil
}
}
用法:
if UIScreen.mainScreen().isRetina() {
// your code
}
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");
}