Reuse Xcode screen size acquisition code CGSize sc = [[UISscreen mainScreen] bounds].size;

For screen size-dependent codes, I believe that writing the auto-layout will reduce the number of actual pixels in the screen size, but I will answer on the premise that it is separate from the auto-layout.

How about creating a subclass of UIApplication and defining a read-only property called screenSize and running screenSize at init?

The sample code is as follows

[Application Name].h

#import<UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@ interface [application name]:UIApplication
@property(readonly) CGSize screenSize;

@end

NS_ASSUME_NONNULL_END

Application Name .m

#import "[Application Name].h"

@implementation [Application Name]
@synthesize screenSize;

- (nonnull instance type) init
{
    self=[super init];
    if(self){
        screenSize = [[UISscreen mainScreen] bounds].size;
    }

    return self;
}

@end

To take advantage of this, add an item to info.plist, select principal class, and write the Application Name in the right column.

You can also use the screenSize source file you want to browse to

#import "[Application Name].h"

where screenSize is required.

CGSize screenSize=([Application Name] *) [UIAApplication sharedApplication]).screenSize;

You can then view the screenSize obtained when starting the application.

After all, it's troublesome, so I don't think it's that different every time I write it, but I hope it'll be helpful if the variable I want to use again (readwrite) and constant (readonly) increase.