需求：app启动的时候总是会显示许许多多的弹窗，那么有一个需求就是让这种弹窗一个个的显示，点掉一个显示下一个。碰到这样的需求该如何搞定呢。
解决方案：有2种实现方案，第一种是创建一个弹窗池来管控弹窗顺序，第二种是利用线程、信号量来完成顺序执行。
第一种方案：
封装GYPopupManager弹窗池，里面维护了一个弹窗的数组。
//
// GYPopupManager.h
// testUI
//
// Created by gaoyu on 2021/9/8.
//
/**
⚠️⚠️⚠️：GYPopupManager
此管理类不关心弹窗的show和hide
只约束弹窗是否被拦截一个一个展示、或者某几个同时展示
*/
#import <Foundation/Foundation.h>
///优先级枚举
typedef NS_ENUM(NSUInteger, GYPopupPriority) {
GYPopupPriorityLow = 1, /// 低
GYPopupPriorityMedium, /// 中
GYPopupPriorityHigh /// 高
};
/// 回调
typedef void (^GYPopupBlock)(void);
// MARK: - GYPopupConfig 弹出内容配置信息
@interface GYPopupConfig : NSObject
/// 是否被拦截：默认YES
@property (nonatomic, assign) BOOL isIntercept;
/// 当前弹窗是否在展示
@property (nonatomic, assign) BOOL isShowing;
/// 弹窗优先级：默认为High（相同优先级的弹窗后加入的先展示，因为字典添加元素后默认会在第一位，所以转化为数组后也是第一个）
@property (nonatomic, assign) GYPopupPriority priority;
/// 弹窗标识：以类名为标识，便于排查
@property (nonatomic, copy, nonnull) NSString *popupClassName;
/// 展示回调
@property (nonatomic, copy, nonnull) GYPopupBlock showBlock;
/// 隐藏回调
@property (nonatomic, copy, nullable) GYPopupBlock dismissBlock;
@end
// MARK: - GYPopupManager 弹出内容管理类
@interface GYPopupManager : NSObject
/// 单例对象
+ (instancetype _Nonnull)shared;
/// 展示弹窗
/// @param popupClass 弹出内容class
/// @param showBlock 展示回调
/// @param dismissBlock 隐藏回调
- (void)popupWithClass:(_Nonnull Class)popupClass show:(_Nonnull GYPopupBlock)showBlock dismiss:(_Nullable GYPopupBlock)dismissBlock;
/// 展示弹窗
/// @param popupClass 弹出内容class
/// @param priority 优先级
/// @param showBlock 展示回调
/// @param dismissBlock 隐藏回调
- (void)popupWithClass:(_Nonnull Class)popupClass priority:(GYPopupPriority)priority show:(_Nonnull GYPopupBlock)showBlock dismiss:(_Nullable GYPopupBlock)dismissBlock;
/// 展示弹窗
/// @param popupClass 弹出内容class
/// @param priority 优先级
/// @param isIntercept 是否需要被拦截
/// @param showBlock 展示回调
/// @param dismissBlock 隐藏回调
- (void)popupWithClass:(_Nonnull Class)popupClass priority:(GYPopupPriority)priority isIntercept:(BOOL)isIntercept show:(_Nonnull GYPopupBlock)showBlock dismiss:(_Nullable GYPopupBlock)dismissBlock;
/// 隐藏弹窗
- (void)dismissPopup;
@end
.m实现
//
// GYPopupManager.m
// testUI
//
// Created by gaoyu on 2021/9/8.
//
#import "GYPopupManager.h"
// MARK: - PRAlertViewConfig
@implementation GYPopupConfig
- (instancetype)init {
self = [super init];
if (self) {
self.isIntercept = YES;
self.popupClassName = @"defaultName";
self.priority = GYPopupPriorityHigh;
}
return self;
}
@end
// MARK: - GYPopupManager
@interface GYPopupManager()
/// 弹出池：key：弹窗className、value：config对象
@property (nonatomic, strong) NSMutableDictionary *popupPool;
/// 当前弹窗内容
@property (nonatomic, strong) GYPopupConfig *currnetPopup;
@end
@implementation GYPopupManager
static GYPopupManager *_instance = nil;
+ (instancetype)shared {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_instance = [[GYPopupManager alloc] init];
});
return _instance;
}
// MARK: - Public Methods
- (void)popupWithClass:(Class)popupClass show:(GYPopupBlock)showBlock dismiss:(GYPopupBlock)dismissBlock{
[self popupWithClass:popupClass priority:GYPopupPriorityHigh isIntercept:YES show:showBlock dismiss:dismissBlock];
}
- (void)popupWithClass:(Class)popupClass priority:(GYPopupPriority)priority show:(GYPopupBlock)showBlock dismiss:(GYPopupBlock)dismissBlock {
[self popupWithClass:popupClass priority:priority isIntercept:YES show:showBlock dismiss:dismissBlock];
}
- (void)popupWithClass:(Class)popupClass priority:(GYPopupPriority)priority isIntercept: (BOOL)isIntercept show:(GYPopupBlock)showBlock dismiss:(GYPopupBlock)dismissBlock {
GYPopupConfig *config = [[GYPopupConfig alloc] init];
config.popupClassName = NSStringFromClass(popupClass);
config.priority = priority;
config.isIntercept = isIntercept;
[self popupWithConfig:config show:showBlock dismiss:dismissBlock];
}
// MARK: - Private Methods
- (void)popupWithConfig:(GYPopupConfig *)config show:(GYPopupBlock)showBlock dismiss:(GYPopupBlock)dismissBlock {
config.showBlock = showBlock;
config.dismissBlock = dismissBlock;
config.isShowing = YES;
// 加入弹出池，同一个弹窗避免重复添加
[self.popupPool setObject:config forKey:config.popupClassName];
// 当前有弹窗在显示：self.popupPool.allKeys.count > 1
// 当前弹窗被拦截：isIntercept == YES
if (config.isIntercept && self.popupPool.allKeys.count > 1) {
config.isShowing = NO;
return;
}
self.currnetPopup = config;
//回主线程
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
showBlock ? showBlock() : nil;
});
}
/// 清除弹出内容
- (void)dismissPopup {
// 获取到当前弹出内容并删除
[self deletePopupWithConfig:self.currnetPopup];
// 是否有弹窗在显示 是：拦截其他未显示弹窗；否：查看是否有下一个可显示弹窗并显示
if ([self isShowingSomeAlert]) {
return;
} else {
// 优先级排序
NSArray * values = [self.popupPool allValues];
values = [self sortByPriority:values];
// 当前没有正在展示的弹窗，则展示被拦截的弹窗
if (values.count > 0) {
// 查询是否有可以展示的弹窗：条件：1.已加入缓存、2.被拦截 3、实现了展示回调
// 优先级 1 > 2 > 3
// 找到一个立即展示，并退出循环（相同优先级的弹窗后加入的先展示，因为字典添加元素后默认会在第一位，所以转化为数组后也是第一个）
for (GYPopupConfig *config in values) {
GYPopupBlock showBlock = config.showBlock;
if (config.isIntercept && showBlock) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
config.isShowing = YES;
self.currnetPopup = config;
showBlock();
});
break;
}
}
}
}
}
/// 是否正在展示某个弹窗
- (BOOL)isShowingSomeAlert{
__block BOOL isShowSomeAlert = NO;
[self.popupPool enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
GYPopupConfig *config = obj;
if (config.isShowing) {
isShowSomeAlert = YES;
*stop = YES;
}
}];
return isShowSomeAlert;
}
/// 根据优先级排序
/// @param configArray 弹窗配置数组
- (NSArray *)sortByPriority:(NSArray *)configArray {
NSComparator comparator = ^(GYPopupConfig *obj1, GYPopupConfig *obj2) {
if (obj1.priority > obj2.priority) {
return NSOrderedAscending;
}
if (obj1.priority < obj2.priority) {
return NSOrderedDescending;
}
return NSOrderedSame;
};
return [configArray sortedArrayUsingComparator:comparator];
}
/// 根据配置删除指定弹出内容
/// @param config 弹出配置
- (void)deletePopupWithConfig:(GYPopupConfig *)config {
if (config == nil) return;
GYPopupBlock dismissBlock = config.dismissBlock;
dismissBlock ? dismissBlock() : nil;
if ([self.popupPool.allKeys containsObject:config.popupClassName]) {
[self.popupPool removeObjectForKey:config.popupClassName];
}
self.currnetPopup = nil;
}
// MARK: - Getters
- (NSMutableDictionary *)popupPool {
if (!_popupPool) {
_popupPool = [[NSMutableDictionary alloc] init];
}
return _popupPool;
}
@end
把弹窗全部加到封装好的GYPopupManager弹窗池中
[[GYPopupManager shared] popupWithClass:[Toast class] priority:GYPopupPriorityMedium show:^{
// 弹窗的展示
[[Toast shared] show];
} dismiss:^{
}];
// 弹窗消失
[[GYPopupManager shared] dismissPopup];
第二种方案：
通过子线程+信号量去阻塞后续弹窗的展示，来完成顺序弹窗
思路：
创建全局只容纳1个单位的信号量
Show的时候 Lock
Dismiss的时候 Release Lock
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface BaseAlertView : UIView
- (void)show;
- (void)dismiss;
@end
NS_ASSUME_NONNULL_END
.m实现
#import "BaseAlertView.h"
//全局信号量
dispatch_semaphore_t _globalInstancesLock;
//执行QUEUE的Name
char *QUEUE_NAME = "com.alert.queue";
//初始化 -- 借鉴YYWebImage的写法
static void _AlertViewInitGlobal() {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_globalInstancesLock = dispatch_semaphore_create(1);
});
}
@implementation BaseAlertView
- (instancetype)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:[UIScreen mainScreen].bounds];
if (self)
{
_AlertViewInitGlobal();
}
return self;
}
#pragma mark - public
- (void)show
{
//位于非主线程 不阻塞
dispatch_async(dispatch_queue_create(QUEUE_NAME, DISPATCH_QUEUE_SERIAL), ^{
//Lock
dispatch_semaphore_wait(_globalInstancesLock, DISPATCH_TIME_FOREVER);
//保证主线程UI操作
dispatch_async(dispatch_get_main_queue(), ^{
[[UIApplication sharedApplication].windows.firstObject addSubview:(UIView *)self];
});
});
}
- (void)dismiss
{
dispatch_async(dispatch_queue_create(QUEUE_NAME, DISPATCH_QUEUE_SERIAL), ^{
//Release Lock
dispatch_semaphore_signal(_globalInstancesLock);
dispatch_async(dispatch_get_main_queue(), ^{
[self removeFromSuperview];
});
});
}
@end
实现方法：弹窗的view继承于BaseAlertView，在展示的时候调用父类的show方法即可。
