ios 倒计时 （离开界面再回来继续）

ios 倒计时 （离开界面再回来继续）

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#import <Foundation/Foundation.h>typedef NS_ENUM(NSInteger, wherefrom){     from1 = 1,               from2 = 2,                from3 = 3,            };@interface cutDownManager : NSObject{    dispatch_source_t _timer;}@property (nonatomic,assign)__block int timeLeft;@property (nonatomic,assign) wherefrom from;  //用于区别哪个倒计时+ (id)sharedTimerManager;- (void)countDown;@end

#import "cutDownManager.h"@implementation cutDownManager+ (id)sharedTimerManager{    static cutDownManager *manager =nil;    static dispatch_once_t onceToken;    dispatch_once(&onceToken, ^{        if (manager ==nil) {            manager = [[self alloc] init];        }    });    return manager;}- (void)countDown{    if (_timeLeft >0) {        if (_timer) {            dispatch_source_cancel(_timer);        }        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);        _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,0, 0,queue);        dispatch_source_set_timer(_timer,dispatch_walltime(NULL,0),1.0*NSEC_PER_SEC,0); //每秒执行        dispatch_source_set_event_handler(_timer, ^{            if(_timeLeft<=0){//倒计时结束，关闭                dispatch_source_cancel(_timer);            }else{                _timeLeft--;                DLog(@"----lefttime ======%d",_timeLeft);            }        });        dispatch_resume(_timer);    }}@end

应用

//获取短信验证码- (IBAction)getMsgCode{   timeout = 60; //倒计时时间  [self startTime];}-(void)startTime{    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);    _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,queue);    dispatch_source_set_timer(_timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0); //每秒执行    dispatch_source_set_event_handler(_timer, ^{        if(timeout<=0){ //倒计时结束，关闭            dispatch_source_cancel(_timer);            dispatch_async(dispatch_get_main_queue(), ^{                //设置界面的按钮显示 根据自己需求设置                _getMsglabel.text = @"重新获取";                _getMsgBtn.userInteractionEnabled = YES;            });        }else{            int seconds = timeout % 120;            NSString *strTime = [NSString stringWithFormat:@"%.2d", seconds];            dispatch_async(dispatch_get_main_queue(), ^{                //设置界面的按钮显示 根据自己需求设置                _getMsglabel.text = [NSString stringWithFormat:@"%@s",strTime];                _getMsgBtn.userInteractionEnabled = NO;            });            timeout--;            DLog(@"---------%d",timeout);        }    });    //启动    dispatch_resume(_timer);}-(void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:animated];    //掐掉倒计时//    if (_timer && timeout > 0) {//        dispatch_source_cancel(_timer);//    }    if (timeout >0) {        cutDownManager *manager = [cutDownManager sharedTimerManager];            manager.timeLeft = timeout;            manager.from = from1;            [manager countDown];        timeout = 0;//置为0，释放controller    }}-(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];    cutDownManager *manager = [cutDownManager sharedTimerManager];    int temp = manager.timeLeft;    if (temp > 0 && (manager.from == from1)) {        timeout = temp;//倒计时时间        _getMsgBtn.enabled =NO;        [self startTime];    }else{        _getMsgBtn.enabled =YES;    }}