“给马一个规则，让它只能走日”设计模式

在我心里，面向对象应该是这样的:

“给马一个规则，让它只能走日”设计模式

而MVVM看上去是将方法从VC分离出来，但是并没有这种感觉，所以我就尝试用我想要的方式写了一个象棋棋子“马”，我称这种设计模式为“给马一个规则，让它只能走日”设计模式.

讲之前先说一下WWeChat，其实更新了，只是没写讲解…改动的还是挺多的，代码在这里.

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效果图:

Chess.gif

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下面讲我这种设计模式（如果你有建议，欢迎指出！）

• 首先我创建了一个UIButtom,名字是Chess

  顾名思义，这个类是所有棋子的父类

.h

 

 

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/** *  棋子上的Label */ @property (nonatomic,strong)UILabel * categoryLabel;   /** *  棋子的类别 (红，黑)默认为红 */ @property (nonatomic,assign)BOOL isRed;   /** *  棋子的状态 (拿起，放下)默认为放下 */ @property (nonatomic,assign)BOOL isInAir;   /** *  每格的宽度 */ @property (nonatomic,assign)CGFloat rowWidth;   /** *  目前的行列 */ @property (nonatomic,copy)NSIndexPath * index;   - (instancetype)initWithRowWidth:(CGFloat)rowWidth andRowLine:(NSIndexPath *)index;

.m

 

 

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- (instancetype)initWithRowWidth:(CGFloat)rowWidth andRowLine:(NSIndexPath *)index {     if (self = [super init])     {         _isRed = YES;           _isInAir = NO;           _index = index;           _rowWidth = rowWidth;           self.backgroundColor = [UIColor clearColor];           //行         NSInteger row = index.row;           //列         NSInteger line = index.section;           if (row > 5)         {             self.frame = CGRectMake(row * rowWidth - rowWidth/2.0 , line * rowWidth - rowWidth/2.0 + rowWidth, rowWidth, rowWidth);         }         else         {             self.frame = CGRectMake(row * rowWidth - rowWidth/2.0, line * rowWidth - rowWidth/2.0,rowWidth, rowWidth);         }           self.categoryLabel = ({               UILabel * categoryLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, rowWidth, rowWidth)];               categoryLabel.textColor = _isRed == YES ? [UIColor redColor] : [UIColor blackColor];               categoryLabel.textAlignment = NSTextAlignmentCenter;               categoryLabel.adjustsFontSizeToFitWidth = YES;               categoryLabel.backgroundColor = [UIColor whiteColor];               categoryLabel.layer.cornerRadius = rowWidth/2.0;               categoryLabel.clipsToBounds = YES;               categoryLabel.layer.borderColor = [UIColor grayColor].CGColor;             categoryLabel.layer.borderWidth = 2;               categoryLabel;         });         [self addSubview:_categoryLabel];           [self addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];     }     return self; }   - (void)btnClick:(UIButton *)sender {     self.isInAir = !self.isInAir;         if (self.isInAir == YES)     {         self.categoryLabel.backgroundColor = [UIColor blackColor];     }     else     {         self.categoryLabel.backgroundColor = [UIColor whiteColor];     }       NSLog(@"%@",_isInAir == YES?@"拿起":@"放下"); }   - (void)setIsRed:(BOOL)isRed {     _isRed = isRed;     _categoryLabel.textColor = _isRed == YES ? [UIColor redColor] : [UIColor blackColor]; }

通过这些代码，棋子获得了被拿起、放下以及分红方、黑方的能力.

• 然后给它创建一个类别Chess+Move

 

 

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- (void)moveToIndex:(NSIndexPath *)index {     [UIView animateWithDuration:0.5 animations:^{           //行         NSInteger  row = index.row;           //列         NSInteger  line = index.section;           if (row > 5)         {             self.frame = CGRectMake(line * self.rowWidth - self.rowWidth/2.0 , row * self.rowWidth - self.rowWidth/2.0 , self.rowWidth, self.rowWidth);         }         else         {             self.frame = CGRectMake(line * self.rowWidth - self.rowWidth/2.0, row * self.rowWidth - self.rowWidth/2.0,self.rowWidth, self.rowWidth);         }           }         completion:^(BOOL finished)        {                self.isInAir = NO;              self.categoryLabel.backgroundColor = [UIColor whiteColor];              self.index = index;          }]; }

让棋子获得任意移动的能力，不写在Chess里面，而是写到Chess+Move里面，我感觉更符合面向对象。

• 现在Chess已经可以了，现在创建一个马

  创建Chess的子类House，获得棋子的基本能力，

 

 

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#import "Chess.h"   @interface House : Chess   - (void)newChess;   @end

 

 

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//House里面只要给Label一个text就够了. - (void)newChess {     self.categoryLabel.text = @"马"; }

• 创建House+rule，让马只能走日的规则

 

 

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- (BOOL)canMoveToIndex:(NSIndexPath *)index {     NSInteger  toRow = index.row;       NSInteger  toLine = index.section;       NSInteger  fromRow = self.index.row;       NSInteger  fromLine = self.index.section;       if(ABS(toLine - fromLine) == 1 & ABS(toRow - fromRow) == 2)     {         return YES;     }     else if(ABS(toLine - fromLine) == 2 & ABS(toRow - fromRow) == 1)     {         return YES;     }     else     {         return NO;     } }

• 创建棋盘UIView类的Map

.h

 

 

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/** *  每格的宽度 */ @property (nonatomic,assign)CGFloat rowWidth;     - (instancetype)initWithStartPt:(CGPoint)pt andRowWidth:(CGFloat)rowWidth;

.m

 

 

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- (instancetype)initWithStartPt:(CGPoint)pt andRowWidth:(CGFloat)rowWidth {     if (self = [super init])     {         _rowWidth = rowWidth;           self.frame = CGRectMake(pt.x, pt.y, rowWidth * 8, rowWidth * 8 + rowWidth);           self.backgroundColor = [UIColor grayColor];           //画列线         for (int j = 0 ; j < 2; j++)         {             for (int i = 0 ; i < 9; i++)             {                 UIView * line = [[UIView alloc]init];                 line.backgroundColor = [UIColor whiteColor];                   if (j == 0)                 {                   line.frame =CGRectMake(i * rowWidth - 1 , 0, 2 , (self.frame.size.height - rowWidth)/2.0);                 }                 else                 {                   line.frame =CGRectMake(i * rowWidth - 1 , (self.frame.size.height - rowWidth)/2.0 + rowWidth, 2 , (self.frame.size.height - rowWidth)/2.0);                 }                 [self addSubview:line];             }         }           //画行线         for (int i = 0; i < 10; i++)         {             UIView * line = [[UIView alloc]init];                  line.frame = CGRectMake(0, i * rowWidth - 1 , self.frame.size.width , 2);               line.backgroundColor = [UIColor whiteColor];             [self addSubview:line];         }     }     return self; }

这里看看就行了，就是画线。

• 走马

  在Map中创建一个点击事件

 

 

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- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {     UITouch * touch = [touches anyObject];     CGPoint  pt = [touch locationInView:self];       //行     NSInteger row = floor((pt.y - _rowWidth/2.0)  / _rowWidth) + 1 ;       //列     NSInteger line = floor((pt.x - _rowWidth/2.0)  / _rowWidth) + 1 ;       for (UIView * view in self.subviews)     {         if ([view isKindOfClass:[Chess class]])         {             //马             if ([view isKindOfClass:[House class]])             {                 House * house = (House *)view;                 if (house.isInAir == YES)                 {                     if ([house canMoveToIndex:[NSIndexPath indexPathForRow:row inSection:line]])                     {                         [house moveToIndex:[NSIndexPath indexPathForRow:row inSection:line]];                     }                 }             }            //其他棋子             else             {               }         }     }       NSLog(@"row:%ld line:%ld",row,line); }

整个项目我都用了一个方法来避开复杂的位置计算，将虚拟的棋盘，化成一部分一部分，根据行、列来确定棋子位置.

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总结

可以看出，我在这里通过类别和继承来使一个Button变成了一个只能走日的棋子“马”，这样的模式，我感觉更符合面向对象的思想.
做其他棋子也会非常简单，只需要再创建属于其他棋子的类别（规则）就行了。
还是那句话！有建议欢迎指出，大家一起讨论！