FGPopupView

1、基本使用

FGPopupScheduler *Scheduler = FGPopupSchedulerGetForPSS(FGPopupSchedulerStrategyFIFO);
AnimationShowPopupView *pop1 =  [[AnimationShowPopupView alloc] initWithDescrption:@"自定义动画 pop2" scheduler:Scheduler];
ConditionsPopView *pop2 =  [[ConditionsPopView alloc] initWithDescrption:@"条件弹窗 pop3 Discard" scheduler:Scheduler];

[Scheduler add:pop];
[Scheduler add:pop2];

2、AnimationShowPopupView、ConditionsPopView都是需要实现FGPopupView protocol的NSObject（一般是一个UIView的类）

FGPopupView protocol中的方法都是optional可选的：

@protocol FGPopupView <NSObject>

@optional
/*
 FGPopupSchedulerStrategyQueue会根据 -showPopupView: 做显示逻辑，如果含有动画请实现-showPopupViewWithAnimation:方法
 */
- (void)showPopupView;

/*
 FGPopupSchedulerStrategyQueue会根据 -dismissPopupView: 做隐藏逻辑，如果含有动画请实现-showPopupViewWithAnimation:方法
 */
- (void)dismissPopupView;

/*
 FGPopupSchedulerStrategyQueue会根据 -showPopupViewWithAnimation: 来做显示逻辑。如果block不传可能会出现意料外的问题
 */
- (void)showPopupViewWithAnimation:(FGPopupViewAnimationBlock)block;

/*
 FGPopupSchedulerStrategyQueue会根据 -dismissPopupView: 做隐藏逻辑，如果含有动画请实现-dismissPopupViewWithAnimation:方法，如果block不传可能会出现意料外的问题
 */
- (void)dismissPopupViewWithAnimation:(FGPopupViewAnimationBlock)block;

/**
 FGPopupSchedulerStrategyQueue会根据-canRegisterFirstPopupView判断，当队列顺序轮到它的时候是否能够成为响应的第一个优先级PopupView。默认为YES
 */
- (BOOL)canRegisterFirstPopupViewResponder;

/** 0.4.0 新增*/

/**
 FGPopupSchedulerStrategyQueue 会根据 - popupViewUntriggeredBehavior：来决定触发时弹窗的显示行为，默认为 FGPopupViewUntriggeredBehaviorAwait
 */
- (FGPopupViewUntriggeredBehavior)popupViewUntriggeredBehavior;


/**
 FGPopupViewSwitchBehavior 会根据 - popupViewSwitchBehavior：来决定已经显示的弹窗，是否会被后续更高优先级的弹窗锁影响，默认为 FGPopupViewSwitchBehaviorAwait  ⚠️⚠️ 只在FGPopupSchedulerStrategyPriority生效
 */
- (FGPopupViewSwitchBehavior)popupViewSwitchBehavior;

@end

3、调度策略

typedef NS_ENUM(NSUInteger, FGPopupSchedulerStrategy) {
    FGPopupSchedulerStrategyFIFO = 1 << 0,           //先进先出
    FGPopupSchedulerStrategyLIFO = 1 << 1,           //后进先出
    FGPopupSchedulerStrategyPriority = 1 << 2        //优先级调度
};

可以根据需求选择合适的策略，另外实际上还可以结合 FGPopupSchedulerStrategyPriority | FGPopupSchedulerStrategyFIFO 一起使用，来处理当选择优先级策略时，如何决定同一优先级弹窗的排序。

4、触发策略

用户可以根据它来决定，当弹窗触发显示逻辑时是否要继续等待

typedef NS_ENUM(NSUInteger, FGPopupViewUntriggeredBehavior) {
    FGPopupViewUntriggeredBehaviorDiscard,          //未满足条件时会被直接丢弃
    FGPopupViewUntriggeredBehaviorAwait,          //未满足条件时会继续等待
};

5、添加策略

在使用FGPopupSchedulerStrategyPriority时碰到优先级相同时，应该如何添加，这里有两个选择，一个先进先出，一个先进后出

typedef NS_ENUM(NSUInteger, FGPopupPriorityAddStrategy) {
    FGPopupPriorityAddStrategyFIFO, //FIFO
    FGPopupPriorityAddStrategyLIFO, //LIFO
};

6、切换策略

目前支持3种切换行为, 用户可以根据它来决定，当该弹窗已经显示时，是否会被后续高优线级的弹窗影响。仅在优先级调度策略时生效：FGPopupSchedulerStrategyPriority

typedef NS_ENUM(NSUInteger, FGPopupViewSwitchBehavior) {
    FGPopupViewSwitchBehaviorDiscard,  //当该弹窗已经显示，如果后面来了弹窗优先级更高的弹窗时，显示更高优先级弹窗并且当前弹窗会被抛弃
    FGPopupViewSwitchBehaviorLatent,   //当该弹窗已经显示，如果后面来了弹窗优先级更高的弹窗时，显示更高优先级弹窗并且当前弹窗重新进入队列, PS：优先级相同时同 FGPopupViewSwitchBehaviorDiscard
    FGPopupViewSwitchBehaviorAwait,    //当该弹窗已经显示时，不会被后续高优线级的弹窗影响
};

7、核心逻辑

//类FGPopupScheduler

//注册observer 通过Runloop监听主线程空闲的时刻
+ (void)initialize{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        CFRunLoopObserverRef observer = CFRunLoopObserverCreate(CFAllocatorGetDefault(), kCFRunLoopBeforeWaiting | kCFRunLoopExit, true, 0xFFFFFF, FGRunLoopObserverCallBack, nil);
        CFRunLoopAddObserver(CFRunLoopGetMain(), observer, kCFRunLoopCommonModes);
        CFRelease(observer);
    });
}
/*
以下三个方法调用了registerFirstPopupViewResponder
*/
- (void)setSuspended:(BOOL)suspended{
    dispatch_async_main_safe(^(){
        self->_suspended = suspended;
        if (!suspended) [self registerFirstPopupViewResponder];
    });
}
//添加弹窗对象的时候
- (void)add:(id<FGPopupView>)view  Priority:(FGPopupStrategyPriority)Priority{
    dispatch_async_main_safe(^(){
        [self->_list addPopupView:view Priority:Priority];
        [self registerFirstPopupViewResponder];
    });
}
//通过Runloop监听主线程空闲的时刻
static void FGRunLoopObserverCallBack(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info){
    for (FGPopupScheduler *scheduler in FGPopupSchedulers()) {
        if (![scheduler isEmpty]) {
            [scheduler registerFirstPopupViewResponder];
        }
    }
}

//类FGPopupScheduler
/**
 向调度器主动发送一个执行显示弹窗的命令, 支持线程安全
 */
- (void)registerFirstPopupViewResponder{
    if (!self.suspended && self.canRegisterFirstPopupViewResponder) {
        dispatch_async_main_safe(^(){
            [self->_list execute];
        });
    }
}
//类FGPopupScheduler
/**
 返回当前调度器是否拥有已经显示的弹窗, 如果canRegisterFirstPopupViewResponder为true，-registerFirstPopupViewResponder将执行无效
 */
@property (nonatomic, assign, readonly) BOOL canRegisterFirstPopupViewResponder;



//类FGPopupList : NSObject <FGPopupSchedulerStrategyQueue> 
//FGPopupSchedulerStrategyQueue可在第8点查看

/*这里有个疑问，这里传进来的priority并没有存储也没有使用不会影响功能？
答案是不会，因为FGPopupList是基类，其子类FGPopupPriorityList对这个方法进行了重写，
这也对应了其仅在优先级调度策略时生效：FGPopupSchedulerStrategyPriority
*/
- (void)addPopupView:(id<FGPopupView>)view Priority:(FGPopupStrategyPriority)Priority{
    [self monitorRemoveEventWith:view];
}
//类FGPopupList : NSObject <FGPopupSchedulerStrategyQueue>
- (void)execute{
    PopupElement *elemt = [self _hitTestFirstPopupResponder];
    id<FGPopupView> view = elemt.data;
    if (!view) {
        return;
    }
    self.FirstFirstResponderElement = elemt;
    
    if ([view respondsToSelector:@selector(showPopupViewWithAnimation:)]) {
        [view showPopupViewWithAnimation:^{}];
    }
    else if([view respondsToSelector:@selector(showPopupView)]){
        [view showPopupView];
    }else{
        NSAssert(NO, @"You must have to implementation -showPopupViewWithAnimation: or -showPopupView");
    }
}
//类FGPopupList : NSObject <FGPopupSchedulerStrategyQueue>
/*
 进行第一响应者测试并返回对应的节点
 
 @returns 作为第一响应者的节点
 */
- (PopupElement *)_hitTestFirstPopupResponder{
    PopupElement *element;
    for(auto itor=_list.begin(); itor!=_list.end();) {
        PopupElement *temp = *itor;
        id<FGPopupView> data = temp.data;
        __block BOOL canRegisterFirstPopupViewResponder = YES;
        if ([data respondsToSelector:@selector(canRegisterFirstPopupViewResponder)]) {
            canRegisterFirstPopupViewResponder = [data canRegisterFirstPopupViewResponder];
        }
        
        if (canRegisterFirstPopupViewResponder) {
            element = temp;
            break;
        }
        /// 这里只能由为显示的popup所触发
        else if([data respondsToSelector:@selector(popupViewUntriggeredBehavior)] && [data popupViewUntriggeredBehavior] == FGPopupViewUntriggeredBehaviorDiscard){
            itor = _list.erase(itor++);
        }
        else{
            itor++;
        }
    }
    return element;
}

8、FGPopupSchedulerStrategyQueue

@protocol FGPopupSchedulerStrategyQueue <NSObject>

/**
 向当前队列中添加弹窗对象，根据不同的FGPopupSchedulerStrategy，每个subList自己都需要重构的-addPopupView:方法
 
 @param view 弹窗对象
 @param Priority 优先级
 */
- (void)addPopupView:(id<FGPopupView>)view  Priority:(FGPopupStrategyPriority)Priority;

/**
 从当前队列删除指定的弹窗对象，根据不同的FGPopupSchedulerStrategy，每个subList自己都需要重构的-removePopupView:方法
 */
- (void)removePopupView:(id<FGPopupView>)view;

/**
 从当前队列中进行-hitTest，返回对象作为当前的FirstFirstResponder，并执行显示操作
 */
- (void)execute;

/**
 清除当前队列弹窗，
 */
- (void)clear;

/**
 返回当前队列是否存在弹窗
 */
- (BOOL)isEmpty;

/**
 返回是否能注册新的显示弹窗，如果当前已经有显示的弹窗返回NO
 */
- (BOOL)canRegisterFirstFirstPopupViewResponder;
@end