1 @implementation NJView
2
3 /*
4 -(void)awakeFromNib
5 {
6
7 NSLog(@"awakeFromNib");
8 // 创建CADisplayLink, 默认每秒60次
9 CADisplayLink *display = [CADisplayLink displayLinkWithTarget:self selector:@selector(updataImage)];
10 // 将CADisplayLink加入到消息循环中
11 [display addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
12 }
13 */
14
15
16 - (id)initWithCoder:(NSCoder *)aDecoder
17 {
18 if (self = [super initWithCoder:aDecoder]) {
19 NSLog(@"initWithCoder");
20
21 // NSTimer一般用于定时的更新一些非界面上的数据
22 // [NSTimer scheduledTimerWithTimeInterval:
23 // 0.1 target:self selector:@selector(updataImage) userInfo:nil repeats:YES];
24
25 // 创建CADisplayLink, 默认每秒60次
26 CADisplayLink *display = [CADisplayLink displayLinkWithTarget:self selector:@selector(updataImage)];
27 // 将CADisplayLink加入到消息循环中
28 [display addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
29
30 }
31 return self;
32 }
33
34 - (void)updataImage
35 {
36 [self setNeedsDisplay];
37 }
38
39
40 - (void)drawRect:(CGRect)rect
41 {
42 CGContextRef ctx = UIGraphicsGetCurrentContext();
43 // CGContextClearRect(ctx, rect);
44
45 self.imageY += 10;
46
47 if (self.imageY > rect.size.height) {
48 self.imageY = 0;
49 }
50 // Drawing code
51 UIImage *image = [UIImage imageNamed:@"snow"];
52 [image drawAtPoint:CGPointMake(10, self.imageY)];
53
54
55 }
