我遇到了一个奇怪的问题。iOS 通知服务扩展将从设备中删除附件。
我使用 SDWebImage 来显示和缓存图像,并且我实现了一个通知服务扩展来在通知警报视图中显示图像。
就我而言,图像已经在本地缓存。然后,我单击主页按钮,我的应用程序在后台运行,应用程序安排了一个本地通知,并将缓存图像附加到通知内容中。
见下面的代码:
1.安排本地通知
+ (void)postLocalNotificationGreaterThanOrEqualToiOS10:(LNotification)module body:(NSDictionary *)body {
UNUserNotificationCenter* center = [UNUserNotificationCenter currentNotificationCenter];
UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];
content.sound = [UNNotificationSound defaultSound];
content.body = @"body";
content.userInfo = @{};
//get the image in device to attach into notification
NSError *error;
NSString* imgURL = [body valueForKey:kLocalNotification_Image];
NSString *filePath = [[SDImageCache sharedImageCache] defaultCachePathForKey:imgURL];
NSURL *url = [NSURL URLWithString:[@"file://" stringByAppendingString:filePath]];
UNNotificationAttachment *attachment = [UNNotificationAttachment attachmentWithIdentifier:@"Image" URL:url options:nil error:&error];
if (attachment) {
content.attachments = @[attachment];
}
UNTimeIntervalNotificationTrigger* trigger = [UNTimeIntervalNotificationTrigger triggerWithTimeInterval:1 repeats:NO];
UNNotificationRequest* request = [UNNotificationRequest requestWithIdentifier:@"FiveSecond"
content:content trigger:trigger];
[center addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {
if (error) {
NSLog(@"error: %@", error.localizedDescription);
}
}];
}
2.Notification Service Extension(其实对于本地通知,只有didReceiveNotificationRequest:withContentHandler:被调用了,什么也没做。)
- (void)didReceiveNotificationRequest:(UNNotificationRequest *)request withContentHandler:(void (^)(UNNotificationContent * _Nonnull))contentHandler {
self.contentHandler = contentHandler;
self.bestAttemptContent = [request.content mutableCopy];
NSDictionary *aps = [self.bestAttemptContent.userInfo objectForKey:@"aps"];
if (aps) {
....//For remote notification, modify the notification content here
}
else {
//For local notification, do nothing
}
self.contentHandler(self.bestAttemptContent);
}
- (void)serviceExtensionTimeWillExpire {
// Called just before the extension will be terminated by the system.
// Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
self.contentHandler(self.bestAttemptContent);
}
- (NSString *)downloadImageWithURL:(NSString *)imageURLString imageName:(NSString *)imageName {
....//code will not execute for local notification
}
我发现,我附加到本地通知中的图像将从设备中删除。我的意思是,在我单击通知警报以从后台到前台启动应用程序后,我尝试显示图像,不幸的是,SDWebImageCache 既没有从磁盘也没有从内存中找到缓存。
看了iOS API的preference,没发现附件会被删除。有谁知道我在哪里可以找到这个问题的任何线索?也许我只是忽略了一些重要的事情,请参阅通知服务扩展。
现在,我做了一个临时解决这个问题的方法,在安排本地通知时,复制缓存的图像并另存为另一个名称,然后将其附加到本地通知中。即使是通知服务扩展也会删除附件,它只会删除复制文件,应用程序会从缓存中找到图像。
但是,我真的很想知道为什么会出现这个问题。提前致谢。