ios NSInvocation基本使用

 

为什么要NSInvocation，NSInvocation比performSelector 调用方法，根据方法名可以传递三个参数

1.  
   -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
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3.  
   // performSelector 只能 根据方法名调用 2个参数
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   // 传递一个参数例子
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   [self performSelector:@selector(callWithNumber:andContent:) withObject:@"110"];
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   // 传递二个参数例子
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   [self performSelector:@selector(callWithNumber:andContent:) withObject:@"110" withObject:@"吃放了"];
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   // [self invocation];
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    }
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    -(void)invocation
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    {
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    //1.创建签名:方法名称|参数|返回|谁拥有它,和方法的调用没有关系
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    NSMethodSignature *signature = [ViewController instanceMethodSignatureForSelector:@selector(callWithNumber:andContent:withStatus:)];
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    //创建NSInvocation
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    /*
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    */
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    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
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    invocation.target = self;
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    invocation.selector = @selector(callWithNumber:andContent:withStatus:);
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    NSString *number = @"15376321";
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    NSString *content = @"11222";
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    NSString *status = @"睡觉";
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    //self and _cmd 0-1已经被占用了,已经被方法占用了
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    [invocation setArgument:&number atIndex:2];
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    [invocation setArgument:&content atIndex:3];
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    [invocation setArgument:&status atIndex:4];
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    [invocation invoke];
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    // return invocation;
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    }
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    -(NSString *)call
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    {
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    NSLog(@"call--");
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    return @"wre";
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    }
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    -(void)callWithNumber:(NSString *)number
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    {
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    NSLog(@"call--%@",number);
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    }
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52.  
    -(void)callWithNumber:(NSString *)number andContent:(NSString *)content
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    {
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    NSLog(@"call--%@--%@",number,content);
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    }
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57.  
    -(void)callWithNumber:(NSString *)number andContent:(NSString *)content withStatus:(NSString *)status
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    {
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    NSLog(@"call--%@--%@---%@",number,content,status);
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    }