知识点
NS_SWIFT_UNAVAILABLE("NSInvocation and related APIs not available")在swift中不能使用
NSInvocation可以直接调用某个对象的方法.
NSInvocation和NSMethodSignature搭配使用,可以访问某个类内部定义所有方法私有的公开的都可以.
NSMethodSignature是方法的签名,可以用来获取参数数量,返回值类型,返回值长度,指定参数的类型等,具体见API
NSInvocation的使用
#import "InvocationViewController.h"
#import "UndoManager.h"
@interface InvocationViewController ()
@end
@implementation InvocationViewController
{
UndoManager * undoManage;
}
- (void)viewDidLoad {
[super viewDidLoad];
undoManage = [[UndoManager alloc]init];
//获取方法的对象
//publicInvocation是有返回值的
NSInvocation * publicInvocation = [self buildPublicInvocation];
//privateInvocation无参无返回值
NSInvocation * privateInvocation = [self buildPrivateInvocation];
//有参数的话需要设置参数
//atIndex是在方法中参数的位置,从左往右数,不能是0和1,要记得0和1已经被占用了即可.
NSString * object = @"object";
NSString * object1 = @"object1";
NSString * object2 = @"object2";
[publicInvocation setArgument:&object atIndex:2];
[publicInvocation setArgument:&object1 atIndex:3];
[publicInvocation setArgument:&object2 atIndex:4];
//设置接收返回值的对象
NSString * returnValue;
[publicInvocation setReturnValue:&returnValue];
//调用方法
[publicInvocation invoke];
//接收返回值
NSLog(@"%@",returnValue);
//打印返回值
[publicInvocation getReturnValue:&returnValue];
NSLog(@"publicInvocation:%@",returnValue);
//调用私有方法
[privateInvocation invoke];
// Do any additional setup after loading the view.
}
- (NSInvocation *)buildPublicInvocation{
//初始化方法的签名,需要调用谁的方法就用谁去创建签名,这里是UndoManager这个类的方法.
//初始化方法的签名有两种这里是使用的类方法还有一种是对象方法
NSMethodSignature * signature = [UndoManager instanceMethodSignatureForSelector:@selector(invocationTestObject:withObject1:withObject2:)];
//返回invocation对象
NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:signature];
//设置invocation的目标对象
[invocation setTarget:undoManage];
//设置需要调用的方法,切记需要和signature中的方法一致
[invocation setSelector:@selector(invocationTestObject:withObject1:withObject2:)];
return invocation;
}
- (NSInvocation *)buildPrivateInvocation{
//初始化方法的签名,需要调用谁的方法就用谁去创建签名,这里是UndoManager这个类的方法.
//初始化方法的签名有两种这里是使用的对象方法
NSMethodSignature * signature = [undoManage methodSignatureForSelector:@selector(testMethodSignature)];
NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:signature];
[invocation setTarget:undoManage];
[invocation setSelector:@selector(testMethodSignature)];
return invocation;
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@end
//
// UndoManager.h
// ObjectMode
//
// Created by 董德帅 on 2020/6/25.
// Copyright © 2020 九天. All rights reserved.
//
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface UndoManager : NSObject
- (NSString *)invocationTestObject:(NSString *)object withObject1:(NSString *)object1 withObject2:(NSString *)object2;
@end
NS_ASSUME_NONNULL_END
//
// UndoManager.m
// ObjectMode
//
// Created by 董德帅 on 2020/6/25.
// Copyright © 2020 九天. All rights reserved.
//
#import "UndoManager.h"
@implementation UndoManager
{
}
- (instancetype)init
{
self = [super init];
if (self) {
}
return self;
}
- (void)testMethodSignature{
NSLog(@"私有方法也可以被外界访问");
}
- (NSString *)invocationTestObject:(NSString *)object withObject1:(NSString *)object1 withObject2:(NSString *)object2{
NSLog(@"%@,%@,%@",object,object1,object2);
return @"return";
}
@end
最终的打印结果,可以发现私有的和公开的都能成功的被调用,对于有返回值的必须调用getReturnValue这个方法后设置的接收返回值的对象才会有参数.
截屏2020-06-26下午6.54.25.png
NSUndoManager和NSInvocation结合使用
//
// InvocationViewController.m
// ObjectMode
//
// Created by 董德帅 on 2020/6/25.
// Copyright © 2020 九天. All rights reserved.
//
#import "InvocationViewController.h"
#import "UndoAndInvocation.h"
@interface InvocationViewController ()
@end
@implementation InvocationViewController
{
UndoAndInvocation * undoInvocation;
NSUndoManager * myUndoManager;
}
- (void)viewDidLoad {
[super viewDidLoad];
//NSUndoManager和NSInvocation的结合
[self undoAndInvocation];
// Do any additional setup after loading the view.
}
- (void)undoAndInvocation{
undoInvocation = [UndoAndInvocation new];
myUndoManager = [[NSUndoManager alloc]init];
NSString * object = @"测试专用字符串";
[self addObject:object];
//打印数据
[undoInvocation printData];
//执行撤销操作
[myUndoManager undo];
//打印数据
[undoInvocation printData];
//执行恢复操作
[myUndoManager redo];
//打印数据
[undoInvocation printData];
}
- (void)addObject:(NSString *)object{
NSInvocation * invocation = [self buildAddInvocation];
[invocation setArgument:&object atIndex:2];
[invocation invoke];
[[myUndoManager prepareWithInvocationTarget:self] removeObject:object];;
}
- (void)removeObject:(NSString *)object{
NSInvocation * invocation = [self buildRemovaInvocation];
[invocation setArgument:&object atIndex:2];
[invocation invoke];
[[myUndoManager prepareWithInvocationTarget:self] addObject:object];
}
- (NSInvocation *)buildAddInvocation{
NSMethodSignature * signature = [UndoAndInvocation instanceMethodSignatureForSelector:@selector(addObject:)];
NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:signature];
[invocation setSelector:@selector(addObject:)];
[invocation setTarget:undoInvocation];
return invocation;
}
- (NSInvocation *)buildRemovaInvocation{
NSMethodSignature * signature = [UndoAndInvocation instanceMethodSignatureForSelector:@selector(removeObject:)];
NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:signature];
[invocation setTarget:undoInvocation];
[invocation setSelector:@selector(removeObject:)];
return invocation;
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@end
//
// UndoAndInvocation.h
// ObjectMode
//
// Created by 董德帅 on 2020/6/26.
// Copyright © 2020 九天. All rights reserved.
//
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface UndoAndInvocation : NSObject
- (void)addObject:(NSString *)object;
- (void)removeObject:(NSString *)object;
- (void)printData;
@end
NS_ASSUME_NONNULL_END
//
// UndoAndInvocation.m
// ObjectMode
//
// Created by 董德帅 on 2020/6/26.
// Copyright © 2020 九天. All rights reserved.
//
#import "UndoAndInvocation.h"
@implementation UndoAndInvocation
{
NSMutableArray * arrData;
}
- (instancetype)init
{
self = [super init];
if (self) {
arrData = [NSMutableArray new];
}
return self;
}
- (void)addObject:(NSString *)object{
[arrData addObject:object];
}
- (void)removeObject:(NSString *)object{
[arrData removeObject:object];
}
- (void)printData{
NSLog(@"%@",arrData);
}
@end
