iOS @property properties and @synthesize properties (RPM)

When you define a series of variables, you need to write a lot of getter and setter methods, and their form is similar, so Xcode provides the @property and @synthesize properties, @property used in the. h header file as a declaration, @ Synthesize is used in. m files for implementation.

As below, create a project based on "Command line Tool", called "Property", and create a new student class,

The traditional notation is:

Student.h

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2. //   
4. //Student.h   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import <Foundation/Foundation.h>   
22. @interface Student:nsobject
24. {
26. int  Age ;
28. int  No;
30. }
34. //age getter and setter method declarations   
36. -(int) age;
38. -(void) setage: (int) newage;
42. //no getter and setter method declarations   
44. -(int) No;
46. -(void) Setno: (int) Newno;
50. @end

Student.m

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2. //   
4. //STUDENT.M   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import "Student.h"   
22. @implementation Student
26. implementation of getter and setter method for//age   
28. -(int) age
30. {
32. return  Age ;
34. }
36. -(void) setage: (int) newage
38. {
40. age = NewAge;
42. }
46. implementation of getter and setter method for//no   
48. -(int) No
50. {
52. return  No;
54. }
56. -(void) Setno: (int) Newno
58. {
60. no = Newno;
62. }
66. @end

Main.m

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2. //   
4. //MAIN.M   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import <Foundation/Foundation.h>   
20. #import "Student.h"   
24. int Main (int argc, const char * argv[])
26. {
30. @autoreleasepool {
34. //Insert code here ...   
36. Student *stu = [[Student alloc] init];
38. Stu.age = 100; //This sentence is equivalent to setter method   
40. NSLog (@"Age is%i", stu.age); //Here the Stu.age equivalent getter method   
44. [Stu release];
48. }
50. return  0;
52. }

--------------------------------------------------------------------------------------------------------------- ---------with @property and @synthesize are:

Student.h

[CPP]View Plaincopy

2. //   
4. //Student.h   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import <Foundation/Foundation.h>   
22. @interface Student:nsobject
24. {
26. int  Age ;
28. int  No;
30. }
34. //When the compiler encounters @property, it automatically expands into getter and setter declarations   
36. @property int age ;
38. @property int No;
44. @end

Student.m

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2. //   
4. //STUDENT.M   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import "Student.h"   
22. @implementation Student
26. //@synthesize will automatically generate getter and setter implementations   
28. //@synthesize will access the variable with the same name by default, Age,no,height   
30. //If a variable with the same name is not found, a private variable age,no,height with the same name is automatically generated internally ,   
32. //So these variables in the Student.h can also be omitted from writing.   
34. @synthesize Age,no;
38. @end

Main.m

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2. //   
4. //MAIN.M   
6. // Property   
8. //   
10. //Created by rio.king on 13-8-25.   
12. //Copyright (c) 2013 rio.king. All rights reserved.   
14. //   
18. #import <Foundation/Foundation.h>   
20. #import "Student.h"   
24. int Main (int argc, const char * argv[])
26. {
30. @autoreleasepool {
34. //Insert code here ...   
36. Student *stu = [[Student alloc] init];
38. Stu.age = 100;
40. NSLog (@"Age is%i", Stu.age);
44. [Stu release];
46. }
48. return  0;
50. }

A few notes:

1. In Xcode4.5 and later versions, you can omit @synthesize, the compiler will automatically help you add getter and setter method implementation, and by default will go to access

_age This member variable, if the _age member variable is not found, a private member variable called _age is automatically generated.

2. Video teaching in the proposed variable name with the "_" prefix as the beginning, but I see big Nerd that book is not used, the individual is more accustomed to the big Nerd that way, so the variable name is not prefixed. Y^o^y

Excerpt from: http://blog.csdn.net/chaoyuan899/article/details/10310719