实例讲解设计模式中的命令模式在iOS App开发中的运用

#import <Foundation/Foundation.h>
 
@interface NimoReceiver : NSObject
 
- (void)action;
 
@end

#import "NimoReceiver.h"
 
@implementation NimoReceiver
 
- (void)action
{
    NSLog(@"实际执行");
}
 
@end

#import <Foundation/Foundation.h>
#import "NimoReceiver.h"
#import "NimoInvoker.h"
#import "NimoConcreteCommand.h"
 
int main(int argc, const char * argv[]) {
    @autoreleasepool {
       
        NimoReceiver *receiver = [[NimoReceiver alloc] init];
        NimoConcreteCommand *command = [[NimoConcreteCommand alloc] initWithReceiver:receiver];
        
        NimoInvoker *invoker = [[NimoInvoker alloc] init];
        invoker.command = command;
        [invoker executeCommand];
        
    }
    return 0;
}

#import <Foundation/Foundation.h>
 
@interface NimoReceiver : NSObject
 
- (int)printWithName:(NSString *)name gender:(NSString *)gender age:(int)age;
 
@end

#import "NimoReceiver.h"
 
@implementation NimoReceiver
 
- (int)printWithName:(NSString *)name gender:(NSString *)gender age:(int)age
{
    NSLog(@"My name is %@, %@, %d years old.", name, gender, age);
    return 119;
}
 
@end

#import <Foundation/Foundation.h>
#import "NimoReceiver.h"
 
int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        //用Receiver的实例创建NSInvocation对象，并把Receiver的action作为选择器
        NimoReceiver *receiver = [[NimoReceiver alloc] init];
        NSString *name = @"Lee";
        NSString *gender = @"male";
        int age = 28;
        SEL sel = @selector(printWithName:gender:age:);
        NSMethodSignature *methodSignature = [[receiver class] instanceMethodSignatureForSelector:sel];
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSignature];
        [invocation setTarget:receiver];
        [invocation setSelector:sel];
        [invocation setArgument:&name atIndex:2];
        [invocation setArgument:&gender atIndex:3];
        [invocation setArgument:&age atIndex:4];
        [invocation retainArguments];
        [invocation invoke]; //通过调用NSInvocation对象的invoke方法，完成对Receiver中action的调用
        
        int returnValue = 0;
        [invocation getReturnValue:&returnValue];
        
        NSLog(@"returnValue: %d", returnValue);
    }
    return 0;
}