Countdown. gif

I. Main Functions

Header document.h

1. Creating Method

/**
 * Use this method (or the corresponding init method) to create objects
 *@ How long does Parma countdown downStartTime take to start countdown
 *@ Parma countdown Unit countdown unit time
 *@ Parma model Array requires a countdown model array
 *@ Property name of Parma model DateKey model to store expiration time
 *@ Parma Model CountDownKey Model stores the attribute name for the remaining time
 *@ Is the expiration time stored in Parma model DateType model the remaining time?
 */
-(instancetype)initWithCountDownStartTime: (long)countDownStartTime andCountDownUnit: (double)countDownUnit andModelArray: (NSArray *)modelArray andModelDateKey: (NSString *)modelDateKey andModelCountDownKey: (NSString *)modelCountDownKey andModelDateType: (PYContDownManagerModelDateType)modelDateType;

/**
 * Use this method (or the corresponding init method) to create objects
 * @parma countDownStartTime How long will the countdown begin?
 * @parma countDownUnit Countdown unit time
 * @parma modelArray An array of model s that require countdown
 * @parma modelDateKey model Property name for storage expiration time
 * @parma modelCountDownKey model Property names that store the remaining time
 * @parma modelDateType model Is the expiration time in storage the remaining time?
 */
+(instancetype)countDownManagerWithCountDownStartTime: (long)countDownStartTime andCountDownUnit: (double)countDownUnit andModelArray: (NSArray *)modelArray andModelDateKey: (NSString *)modelDateKey andModelCountDownKey: (NSString *)modelCountDownKey andModelDateType: (PYContDownManagerModelDateType)modelDateType;

2. Common methods:

3. Common attributes

/**
 * Client time, default to the current time of the mobile phone. If there are any deviations, you can adjust them here.
 */
@property (nonatomic,strong) NSDate *clientTime;

3. Logic of concrete realization.

1. Logic

2. Realization

1. create object

   In fact, it is to record the attributes and finally use them. [self createTimer]Create a timer

   #pragma mark - Create objects
   +(instancetype)countDownManagerWithCountDownStartTime: (long)countDownStartTime
                                      andCountDownUnit: (double)countDownUnit
                                         andModelArray: (NSArray *)modelArray
                                       andModelDateKey: (NSString *)modelDateKey
                                  andModelCountDownKey: (NSString *)modelCountDownKey
                                      andModelDateType: (PYContDownManagerModelDateType)modelDateType
   {
    return [[self alloc]initWithCountDownStartTime:countDownStartTime
                                  andCountDownUnit:countDownUnit
                                     andModelArray:modelArray
                                   andModelDateKey:modelDateKey
                              andModelCountDownKey:modelCountDownKey
                                  andModelDateType:modelDateType];
   }
   -(instancetype)initWithCountDownStartTime: (long)countDownStartTime
                          andCountDownUnit: (double)countDownUnit
                             andModelArray: (NSArray *)modelArray
                           andModelDateKey: (NSString *)modelDateKey
                      andModelCountDownKey: (NSString *)modelCountDownKey
                          andModelDateType: (PYContDownManagerModelDateType)modelDateType
   {
    self = [super init];
    if (self) {
        self.countDownStartTime = countDownStartTime;
        self.countDownUnit = countDownUnit;
        self.modelArray = modelArray;
        self.modelDateKey = modelDateKey;
        self.modelCountDownKey = modelCountDownKey;
        self.modelDateType = modelDateType;
        if (!self.timer){
            [self createTimer];
        }
    }
    return self;
   }

2. Timer Creation

   Here it is used. GCD The timer and sub-threads perform data traversal processing, and call back the timing events in the main thread.

   //MARK: Creation of Timer
   -(void)createTimer {
   //0. Create queues
        dispatch_queue_t queue = self.queue;
        //1. Create timers in GCD
        /*
         First parameter: Create the source type DISPATCH_SOURCE_TYPE_TIMER: Timer
         Second parameter: 0
         Third parameter: 0
         The fourth parameter: queue
         */
        dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
         self.timer = timer;
        //2. Setting Timer
        /*
         First parameter: timer object
         The second parameter: DISPATCH_TIME_NOW indicates timing from now on
         Third parameter: the minimum unit of time in the interval GCD is nanoseconds
         Fourth parameter: accuracy (for allowable errors, 0 for absolute accuracy)
         */
        dispatch_source_set_timer(timer, DISPATCH_TIME_NOW, self.countDownUnit * NSEC_PER_SEC, 0 * NSEC_PER_SEC);
        //3. Tasks to be invoked
        dispatch_source_set_event_handler(timer, ^{
            NSLog(@"GCD-----%@",[NSThread currentThread]);
            dispatch_async(self.queue, ^{
                [self lookingForATimelyModelArray:self.modelArray];
                dispatch_async(dispatch_get_main_queue(), ^{
                    if (self.countdownDataFredbackWithBlock) {
                        self.countdownDataFredbackWithBlock();
                    }
                });
            });
        });
        //4. Start execution
        dispatch_resume(timer);
   }

3. Data Processing

   1.This method has been done in sub-threads, to the outside world. model The array is traversed. The remaining time is calculated.

   -(void)lookingForATimelyModelArray: (NSArray *)modelArray {
    [modelArray enumerateObjectsUsingBlock:^(id  _Nonnull model, NSUInteger idx, BOOL * _Nonnull stop) {
        //If it's still an array, it's convenient once.
        if ([[model class] isSubclassOfClass:NSClassFromString(@"NSArray")]) {
            self.column ++;
            [self lookingForATimelyModelArray:model];
        }
        //Judging the Types of Time Classes in model
        NSString *dateValue = [model valueForKey:self.modelDateKey];
        long long dateNumber = dateValue.longLongValue;       
        //If there is no time value
        if (!dateNumber) return;        
        //Determine whether time difference needs to be calculated
        if (self.modelDateType == PYContDownManagerModelDateType_OriginalTime){
            //Time difference calculation
           dateNumber = [self computationTimeDifferenceWithDateNumber:dateNumber];
        }
        //Determine whether timing is required
        if (dateNumber <= self.countdownStartTime) {
            if ([[model valueForKey:self.modelCountDownKey] isKindOfClass:NSClassFromString(@"NSString")]) {
                [model setValue:@(dateNumber).description forKey:self.modelCountDownKey];
            }else if ([[model valueForKey:self.modelCountDownKey] isKindOfClass:NSClassFromString(@"NSNumber")]) {
                [model setValue:@(dateNumber) forKey:self.modelCountDownKey];
            }
        }
    }];
   }
   //MARK: Calculation of Time Difference
   -(long long)computationTimeDifferenceWithDateNumber: (long long)dateNumber {   
    NSTimeInterval timeInterval = [self.clientTime timeIntervalSince1970];
    return (dateNumber - timeInterval);
   }

4. Transfer Station Connecting with the Outside

// MARK: Interface for External Refresh UI
- (void)countdownDataFredbackWithBlock: (void(^)())countdownDataFredbackWithBlock {
    self.countdownDataFredbackWithBlock = countdownDataFredbackWithBlock;
}

5. Cancel and Open Timer

//MARK: Cancel Timer
-(void)cancelTimer {
    dispatch_cancel(self.timer);
    self.timer = nil;
}
//MARK: Turn on the Timer
-(void)resumeTimer {
    if (!self.timer) {
        [self createTimer];
    }
}