通过代码判断iphone4的Retina 屏幕分辨率

通过代码判断iphone4的Retina 屏幕分辨率

#define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)

-(void)loadMainView

{

    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    UIImage *bigImage = [UIImage imageNamed:@"comment.png"];

    UIImage *smallImage = [UIImage imageNamed:@"[email protected]"];

    if (isRetina) 

    {

        button.frame = CGRectMake(0, 20, bigImage.size.width, bigImage.size.height);

        [button setImage:bigImage forState:UIControlStateNormal];

    }

    else 

    {

        button.frame = CGRectMake(0, 20, smallImage.size.width, smallImage.size.height);

        [button setImage:smallImage forState:UIControlStateNormal];

    }

    

    [button addTarget:self action:@selector(isButtonClicked:) forControlEvents:UIControlEventTouchUpInside];

    [self.window addSubview:button];

}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    [self loadMainView];

   

    self.window.backgroundColor = [UIColor whiteColor];

    [self.window makeKeyAndVisible];

    return YES;

}