设计模式-原型模式

设计模式-原型模式

效果:

原型模式,其实就是完整的复制一个对象,以一个对象为样本,进行复制作业,然后再来使用.

以下以复制一个UIView的操作来讲解原型模式的实现

注:UIView对象是不能够复制的,我们需要完整的把UIView对象的参数都复制了后,就行了.

http://stackoverflow.com/questions/4425939/can-uiview-be-copied

Your app probably crashes with something like:

 [UIView copyWithZone:]: unrecognized selector sent to instance 0x1c6280

The reason is that UIView does not implement the copying protocol, and therefore there is no copyWithZone selector in UIView.

因为UIView没有实现复制的协议,所以也就不能复制UIView了.

UIView+Prototype.h 与 UIView+Prototype.m

//
//  UIView+Prototype.m
//  Copy
//
//  Created by YouXianMing on 14/11/14.
//  Copyright (c) 2014年 YouXianMing. All rights reserved.
//

#import "UIView+Prototype.h"

@implementation UIView (Prototype)

- (UIView *)createPrototype {
    UIView *prototypeView = nil;

    if (self) {
        // 创建出view
        prototypeView                            = [[UIView alloc] initWithFrame:self.frame];

        // 被复制的内容
        prototypeView.transform                  = self.transform;
        prototypeView.contentScaleFactor         = self.contentScaleFactor;
        prototypeView.multipleTouchEnabled       = self.multipleTouchEnabled;
        prototypeView.exclusiveTouch             = self.exclusiveTouch;
        prototypeView.autoresizesSubviews        = self.autoresizesSubviews;
        prototypeView.autoresizingMask           = self.autoresizingMask;
        prototypeView.clipsToBounds              = self.clipsToBounds;
        prototypeView.backgroundColor            = self.backgroundColor;
        prototypeView.alpha                      = self.alpha;
        prototypeView.clearsContextBeforeDrawing = self.clearsContextBeforeDrawing;
        prototypeView.hidden                     = self.hidden;
        prototypeView.contentMode                = self.contentMode;
        prototypeView.tintColor                  = self.tintColor;
        prototypeView.tintAdjustmentMode         = self.tintAdjustmentMode;
    }

    return prototypeView;
}

@end

//
//  UIView+Prototype.h
//  Copy
//
//  Created by YouXianMing on 14/11/14.
//  Copyright (c) 2014年 YouXianMing. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIView (Prototype)

/**
 *  创建当前View的原型
 *
 *  @return 当前view的一个新的实例
 */
- (UIView *)createPrototype;

@end

使用:

//
//  ViewController.m
//  Copy
//
//  Created by YouXianMing on 14/11/14.
//  Copyright (c) 2014年 YouXianMing. All rights reserved.
//

#import "ViewController.h"
#import "UIView+Prototype.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 作为原型的view
    UIView *redView         = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 100, 100)];
    redView.backgroundColor = [UIColor redColor];
    redView.alpha           = 0.5;
    [self.view addSubview:redView];

    // 根据一个原型创建出view
    UIView *greenView         = [redView createPrototype];
    greenView.frame           = CGRectMake(75, 75, 100, 100);
    greenView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:greenView];

    // 根据一个原型创建出view
    UIView *blueView         = [greenView createPrototype];
    blueView.frame           = CGRectMake(100, 100, 100, 100);
    blueView.backgroundColor = [UIColor blueColor];
    [self.view addSubview:blueView];
}

@end

需要注意的地方: