iOS cell上的定时器

  转载地址：http://blog.csdn.net/littleSun_zheng/article/details/51426859

实现原理： 
1、将数据（数据中的时间部分），以字典（字典中包括：记录所存数据下标，还有所剩时间 两个 key）的形式保存到数组中。 
2、开启定时器，执行：遍历整个数组，每秒减 一，然后保存到他原来的位置。 
3、每次减一之后，根据之前记录的下标找到对应的Cell，然后修改上面的数。这样就可以了。 
提示：分组类型的tableView 也是没有一点问题的。效果如APP“E中医”里面的名医出诊功能。 
简单的一个demo: 
command + a 代码（直接粘贴到刚刚新建工程的ViewController.m文件中即可）：

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//  ViewController.m</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//  CountdownDemo</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//  Created by 郑鹏 on 16/5/16.</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//  Copyright © 2016年 littleSun_zheng. All rights reserved.</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#import <span class="hljs-title" style="box-sizing: border-box;">"ViewController.h"</span></span><span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ViewController</span> ()<<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">UITableViewDataSource</span>>{</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//存放假数据的数组</span>    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableArray</span> *_textArry;    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//时间倒计时的 时间数组</span>    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableArray</span> *_totalLastTime;    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//定时器</span>    NSTimer *_timer;    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//记录 indexPath</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> _num;}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">strong</span>)<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableView</span> *tableView;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@end</span><span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@implementation</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ViewController</span></span>- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)viewDidLoad {    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span> viewDidLoad];    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Do any additional setup after loading the view, typically from a nib.</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//模拟倒计时   数据</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//模拟所用数据</span>    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> _modelData];    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化 tableView</span>    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> _creatTableView];    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//处理数据   并  在主线程 开启定时器</span>    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> _operateData];}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#pragma mark--假数据</span>- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)_modelData{    _totalLastTime = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableArray</span> array];    _textArry = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableArray</span> array];    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">101</span>; i++) {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (i%<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span> == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {            [_textArry addObject:[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSNumber</span> numberWithInt:i]];        }    }}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#pragma mark--初始化标视图</span>- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)_creatTableView{    _tableView = [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableView</span> alloc] initWithFrame:CGRectMake(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">64</span>, [UIScreen mainScreen]<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.bounds</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.size</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.width</span> ,[UIScreen mainScreen]<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.bounds</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.size</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.height</span> - <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">64</span>) style:UITableViewStylePlain];    _tableView<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.dataSource</span> = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span>;    _tableView<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.rowHeight</span> = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">44</span>;    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.view</span> addSubview:_tableView];}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#pragma mark -- 处理数据   并  在主线程 开启定时器</span>- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)_operateData{    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (_textArry<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span> != <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i<_textArry<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span>; i++) {            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSNumber</span> *allSecond = _textArry[i];            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span> remainIntSecond = [allSecond integerValue];            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSDictionary</span> *dic = @{@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"indexPath"</span>:[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%i"</span>,i],@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"lastTime"</span>: [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld"</span>,(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span>)remainIntSecond]};            [_totalLastTime addObject:dic];        }    }    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">dispatch_async</span>(dispatch_get_main_queue(), ^{        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//开启定时器</span>        [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> _startTimer];        [_tableView reloadData];    });}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#pragma mark--开启定时器  时处理</span>- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)_startTimer{    _timer = [NSTimer scheduledTimerWithTimeInterval:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1.0</span> target:<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> selector:<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@selector</span>(refreshLessTime) userInfo:<span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">nil</span> repeats:<span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">YES</span>];    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//如果不添加下面这条语句，在UITableView拖动的时候，会阻塞定时器的调用（为什么我还不怎么明白，希望能相互交流）</span>    [[NSRunLoop currentRunLoop] addTimer:_timer forMode:UITrackingRunLoopMode];}- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)refreshLessTime{    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> time;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < _totalLastTime<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span>; i++) {            time = [[[_totalLastTime objectAtIndex:i] objectForKey:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"lastTime"</span>] intValue];            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (time > <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSIndexPath</span> *indexPath = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSIndexPath</span> indexPathForRow:[[[_totalLastTime objectAtIndex:i] objectForKey:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"indexPath"</span>] integerValue] inSection:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableViewCell</span> *cell = [_tableView cellForRowAtIndexPath:indexPath];                cell<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.textLabel</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.text</span> = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%i"</span>, time];                time = time - <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSDictionary</span> *dic = @{@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"indexPath"</span>: [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%d"</span>,i],@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"lastTime"</span>: [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%i"</span>,time]};                [_totalLastTime replaceObjectAtIndex:i withObject:dic];            }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSIndexPath</span> *indexPath = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSIndexPath</span> indexPathForRow:[[[_totalLastTime objectAtIndex:i] objectForKey:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"indexPath"</span>] integerValue] inSection:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];                <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableViewCell</span> *cell = [_tableView cellForRowAtIndexPath:indexPath];                cell<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.textLabel</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.text</span> = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"littleSun倒计时结束"</span>];            }        }}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#pragma mark--UITableViewDataSource</span>- (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span>)tableView:(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableView</span> *)tableView numberOfRowsInSection:(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span>)section{    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> _totalLastTime<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span>;}- (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableViewCell</span> *)tableView:(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableView</span> *)tableView cellForRowAtIndexPath:(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSIndexPath</span> *)indexPath{    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *countdownCell = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"CountdownDemo_Cell"</span>;    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableViewCell</span> *cell = [tableView dequeueReusableCellWithIdentifier:countdownCell];    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (cell == <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">nil</span>) {        cell= [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UITableViewCell</span> alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:countdownCell];    }    <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *remainSecond =  _textArry[indexPath<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.row</span>];    cell<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.textLabel</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.text</span> = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"还剩下：%@ 秒"</span>,remainSecond];    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> cell;}- (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)didReceiveMemoryWarning {    [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span> didReceiveMemoryWarning];    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Dispose of any resources that can be recreated.</span>}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@end</span></code>