1 @interface NJView ()
2 /**
3 * 定义一个大数组(大数组中保存小数组, 每一个小数组保存一条直线所有的点)
4 */
5 @property (nonatomic, strong) NSMutableArray *totalPoints;
6
7 @end
8
9 @implementation NJView
10
11 - (NSMutableArray *)totalPoints
12 {
13 if (_totalPoints == nil) {
14 _totalPoints = [NSMutableArray array];
15 }
16 return _totalPoints;
17 }
18
19 // 开始触摸
20 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
21 {
22 // NSLog(@"touchesBegan");
23
24 // 1.获取手指对应UITouch对象
25 UITouch *touch = [touches anyObject];
26 // 2.通过UITouch对象获取手指触摸的位置
27 CGPoint startPoint = [touch locationInView:touch.view];
28
29 // 3.将手指触摸的起点存储到数组中
30 // [self.points addObject:[NSValue valueWithCGPoint:startPoint]];
31
32 // 3.创建一个小数组,用于保存当前路径所有的点
33 NSMutableArray *subPoints = [NSMutableArray array];
34 // 4.将手指触摸的起点存储到小数组中
35 [subPoints addObject:[NSValue valueWithCGPoint:startPoint]];
36 // 5.将小数组存储到大数组中
37 [self.totalPoints addObject:subPoints];
38
39 }
40 // 移动
41 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
42 {
43 // 1.获取手指对应UITouch对象
44 UITouch *touch = [touches anyObject];
45 // 2.通过UITouch对象获取手指触摸的位置
46 CGPoint movePoint = [touch locationInView:touch.view];
47 // 3.将手指移动时触摸的点存储到数组中
48 // [self.points addObject:[NSValue valueWithCGPoint:movePoint]];'
49 // 4.从大数组中取出当前路径对应的小数组
50 NSMutableArray *subPoints = [self.totalPoints lastObject];
51 // 5.将手指移动时触摸的点存储到小数组中
52 [subPoints addObject:[NSValue valueWithCGPoint:movePoint]];
53
54
55 // 6.调用drawRect方法重回视图
56 [self setNeedsDisplay];
57
58 }
59
60 // 离开view(停止触摸)
61 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
62 {
63 // 1.获取手指对应UITouch对象
64 UITouch *touch = [touches anyObject];
65 // 2.通过UITouch对象获取手指触摸的位置
66 CGPoint endPoint = [touch locationInView:touch.view];
67
68 // 3.将手指离开时触摸的点存储到数组中
69 // [self.points addObject:[NSValue valueWithCGPoint:endPoint]];
70
71 // 4.从大数组中取出当前路径对应的小数组
72 NSMutableArray *subPoints = [self.totalPoints lastObject];
73 // 5.将手指移动时触摸的点存储到小数组中
74 [subPoints addObject:[NSValue valueWithCGPoint:endPoint]];
75
76 // 6.调用drawRect方法重回视图
77 [self setNeedsDisplay];
78
79 }
80
81 // 画线
82 - (void)drawRect:(CGRect)rect
83 {
84
85 // 1.获取上下文
86 CGContextRef ctx = UIGraphicsGetCurrentContext();
87 // 遍历大数组,取出所有的小数组(每一个小数组代表一条线段)
88 for (NSMutableArray *subPointArray in self.totalPoints) {
89 // 遍历小数组, 取出小数组中所有的点
90 for (int index = 0; index < subPointArray.count; index++) {
91 // 1.取出小数组中的每一个点
92 CGPoint point = [subPointArray[index] CGPointValue];
93 // 2.绘制线段
94 if (0 == index) {
95 // 2.1. 设置线段的起点
96 CGContextMoveToPoint(ctx, point.x, point.y);
97 }else
98 {
99 // 2.2.设置线段的终点
100 CGContextAddLineToPoint(ctx, point.x, point.y);
101 }
102 }
103 }
104
105 /*
106 for (int index = 0; index < self.points.count; index++) {
107 CGPoint point = [self.points[index] CGPointValue];
108 // 2.绘制线段
109 if (0 == index) {
110 // 2.1. 设置线段的起点
111 CGContextMoveToPoint(ctx, point.x, point.y);
112 }else
113 {
114 // 2.2.设置线段的终点
115 CGContextAddLineToPoint(ctx, point.x, point.y);
116 }
117
118 }
119 */
120
121 CGContextSetLineCap(ctx, kCGLineCapRound);
122 CGContextSetLineJoin(ctx, kCGLineJoinRound);
123 CGContextSetLineWidth(ctx, 10);
124
125 // 3.渲染
126 CGContextStrokePath(ctx);
127
128 }
129
130 - (void)clearView
131 {
132 [self.totalPoints removeAllObjects];
133 [self setNeedsDisplay];
134 }
135 - (void)backView
136 {
137 [self.totalPoints removeLastObject];
138 [self setNeedsDisplay];
139 }
