object-c之计时器

1 先设置一个定时器
2 TimeInterval：设置时间间隔
3 target：表示发送的对象
4 selector：选择一个实例方法
5 userInfo:此参数可以为nil，当定时器失效时，由你指定的对象保留和释放该定时器
6 
7 [NSTimer scheduledTimerWithTimeInterval:2.0ftarget:self selector:@selector(doTimer:) userInfo:handle repeats:YES];
8 
9 
10 - (void)doTimer:(NSTimer *)timer
11 {
12 ……
13 //计时器失效
14 [timer invalidate];
15 
16 }
17 
18 
19 
20 主函数
21 
22 [timer startWrite];
23 //添加到runloop中后，该定时器将在初始化时指定的timeInterval秒后自动触发。
24 [[NSRunLoop currentRunLoop]run];

1 main.m
2 
3         
4         Timers *timer =[[Timers alloc]init];
5         
6 [timer startWrite];
7         
8 [[NSRunLoop currentRunLoop]run];
9 
10 Timer.h
11 #import <Foundation/Foundation.h>
12 
13 @interfaceTimers : NSObject
14 
15 @property(nonatomic,retain) NSTimer *timer;
16 
17 - (void)startWrite;
18 
19 @end
20 
21 
22 #import "Timers.h"
23 
24 @implementationTimers
25 
26 static int num = 0;
27 
28 
29 - (void)doTimer:(NSTimer *)timer
30 {
31     //处理问题
32     num++;
33     NSFileHandle *handle =[timer userInfo];
34     NSDate *date =[NSDate date];
35     //设置日期格式
36     NSDateFormatter *formatter =[[NSDateFormatter alloc]init];
37     [formatter setAMSymbol:@"上午"];
38     [formatter setPMSymbol:@"下午"];
39     [formatter setDateFormat:@"YYYY年MM月dd日 HH:mm:ss EEE aaa"];
40     
41     //日期格式化
42     NSString *time =[formatter stringFromDate:date];
43     //添加换行
44     NSString *time1 = [time stringByAppendingString:@""];
45     
46     NSData *data =[time1 dataUsingEncoding:NSUTF8StringEncoding];
47     //光标移到文件末尾
48 [handle seekToEndOfFile];
49     //写入数据
50 [handle writeData:data];
51     
52     if (num>=5)
53 {
54 [timer invalidate];
55         NSLog(@"哈哈哈");
56         //[handle closeFile];
57 }
58 }
59 
60 - (void)startWrite
61 {
62     //数据存储路径
63     NSString *path = @"/Users/scjy/Desktop/刘二龙练习/OC/练习1/日期写入/日期写入/dateInsert.txt";
64     
65     NSFileManager *filemanger =[NSFileManager defaultManager];
66     if (![filemanger fileExistsAtPath:path])
67 {
68         //如果文件不存在，创建文件
69 [filemanger createFileAtPath:path contents:nil attributes:nil];
70         
71 }
72     
73     //准备写入
74     NSFileHandle *handle =[NSFileHandle fileHandleForWritingAtPath:path];
75     
76     [NSTimer scheduledTimerWithTimeInterval:2.0ftarget:self selector:@selector(doTimer:) userInfo:handle repeats:YES];
77     
78 }
79 @end