First create a new PCH file and then modify the project's build setting prefix Header to $ (srcroot)/project name/precompiled filename;
The general PCH file is useful:
1, import the framework, such as:
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h> etc.
2. Macro definition
#define Kscreenwidth [UIScreen mainscreen].bounds.size.width // width of the screen
#define Kscreenheight [UIScreen mainscreen].bounds.size.height // screen high
//Interface Data Convenient program outsourcing modify this file for easy
#define Us_box @ "Us_box"//Home Data Interface
#define News_list @ "News_list"//News interface//Set whether debug mode#define DEBUG 1//logoff will not print #ifdef DEBUG
#define NSLOG (S, ...) NSLog (@ "%@", [NSString stringWithFormat: (s), # #__VA_ARGS__])
#else
#define NSLOG (S, ...) #endif//macro defines a function to create a random color
#define RGB (a) [Uicolor colorwithred:arc4random ()%10*.1 green:arc4random ()%10*.1 blue:arc4random ()%10*.1 alpha:a]
//Equipment Model judgment
#define DEVICENUM [[Uidevice currentdevice].systemversion Floatvalue]
precompiling files with PCH