iOS设计模式 - 中介者

iOS设计模式 - 中介者

原理图

说明

用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显式地相互引用，从而使其耦合松散，而且可以独立地改变它们之间的交互。

注：中介者对象本身没有复用价值，只是将逻辑操作封装在一个类里面而已

源码

https://github.com/YouXianMing/iOS-Design-Patterns

//
//  TextFieldMediator.h
//  MediatorPattern
//
//  Created by YouXianMing on 15/10/26.
//  Copyright © 2015年 ZiPeiYi. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface TextFieldMediator : NSObject <UITextFieldDelegate>

@property (nonatomic, weak) UITextField  *textField_1;
@property (nonatomic, weak) UITextField  *textField_2;
@property (nonatomic, weak) UITextField  *textField_3;

@end

//
//  TextFieldMediator.m
//  MediatorPattern
//
//  Created by YouXianMing on 15/10/26.
//  Copyright © 2015年 ZiPeiYi. All rights reserved.
//

#import "TextFieldMediator.h"

@implementation TextFieldMediator

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

    if ([textField isEqual:self.textField_1]) {

        NSString *currentNum  = [self currentStringWithTextField:textField replacementString:string inRange:range];
        self.textField_2.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue * ];
        self.textField_3.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue * ];

    } else if ([textField isEqual:self.textField_2]) {

        NSString *currentNum  = [self currentStringWithTextField:textField replacementString:string inRange:range];
        self.textField_1.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue / ];
        self.textField_3.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue * ];

    } else {

        NSString *currentNum  = [self currentStringWithTextField:textField replacementString:string inRange:range];
        self.textField_1.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue / ];
        self.textField_2.text = [NSString stringWithFormat:@"%.f", currentNum.floatValue / ];
    }

    return YES;
}

- (NSString *)currentStringWithTextField:(UITextField *)textField replacementString:(NSString *)string inRange:(NSRange)range {

    NSMutableString *mutableString = [NSMutableString stringWithString:textField.text];

    if (string.length) {

        [mutableString insertString:string atIndex:range.location];

    } else {

        [mutableString deleteCharactersInRange:range];
    }

    return [NSString stringWithString:mutableString];
}

@end

//
//  ViewController.m
//  MediatorPattern
//
//  Created by YouXianMing on 15/10/26.
//  Copyright © 2015年 ZiPeiYi. All rights reserved.
//

#import "ViewController.h"
#import "TextFieldMediator.h"

@interface ViewController () <UITextFieldDelegate>

@property (nonatomic, strong) UITextField  *textField_1;
@property (nonatomic, strong) UITextField  *textField_2;
@property (nonatomic, strong) UITextField  *textField_3;

@property (nonatomic, strong) TextFieldMediator *mediator;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // 初始化控件
    self.textField_1 = [self createTextFieldWithFrame:CGRectMake(,  +  * , , )];
    self.textField_2 = [self createTextFieldWithFrame:CGRectMake(,  +  * , , )];
    self.textField_3 = [self createTextFieldWithFrame:CGRectMake(,  +  * , , )];
    [self.view addSubview:self.textField_1];
    [self.view addSubview:self.textField_2];
    [self.view addSubview:self.textField_3];

    // 初始化中介者
    self.mediator = [[TextFieldMediator alloc] init];
    self.mediator.textField_1 = self.textField_1;
    self.mediator.textField_2 = self.textField_2;
    self.mediator.textField_3 = self.textField_3;

    // 将代理设置成中介者
    self.textField_1.delegate = self.mediator;
    self.textField_2.delegate = self.mediator;
    self.textField_3.delegate = self.mediator;
}

- (UITextField *)createTextFieldWithFrame:(CGRect)frame {

    UITextField *tmpField      = [[UITextField alloc] initWithFrame:frame];
    tmpField.layer.borderWidth = 0.5f;
    tmpField.keyboardType      = UIKeyboardTypeNumberPad;

    return tmpField;
}

@end

细节