一、正常延长版保活（时间3min-40min不等）
1.定义定时器属性
@property (nonatomic,strong)NSTimer *myTimer;
@property (nonatomic,assign)UIBackgroundTaskIdentifier backgroundTaskIdentifier;
2.代码实现
- (void)applicationDidEnterBackground:(UIApplication *)application{
self.backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
[application endBackgroundTask:self.backgroundTaskIdentifier];
self.backgroundTaskIdentifier = UIBackgroundTaskInvalid;
}];
//开启定时器 不断向系统请求后台任务执行的时间
self.myTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(makeMoreTime) userInfo:nil repeats:YES];
[self.myTimer fire]
}
-(void)makeMoreTime {
//如果系统给的剩余时间小于60秒 就终止当前的后台任务，再重新初始化一个后台任务，重新让系统分配时间，这样一直循环下去，保持APP在后台一直处于active状态。
MSULog(@"1 --- %.2f",[UIApplication sharedApplication].backgroundTimeRemaining);
if ([UIApplication sharedApplication].backgroundTimeRemaining < 60) {
MSULog(@"Background Time Remaining = %.02f Seconds", [UIApplication sharedApplication].backgroundTimeRemaining);
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTaskIdentifier];
self.backgroundTaskIdentifier = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
MSULog(@"重新");
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTaskIdentifier];
self.backgroundTaskIdentifier = UIBackgroundTaskInvalid;
}];
}
二、永久版保活
第一种方式：利用后台定位功能实现，此模式只适合选择“一直允许使用定位”，但是在新系统上会出现如果用户选择“使用app时定位”，就会出现退到后台时候，手机顶部会出现蓝色定位标识，影响用户体验；如果用户拒绝使用定位，就尴尬了，除地图类app，其他app不建议此方式；
第二种方式：利用voip功能实现，此模式适合音视频类app，常规类app也可以考虑使用；voip推送和apns推送是苹果两大推送方式，和apns推送不一样的地方在于，voip推送属于强制推送，用户无法拒绝此推送模式（故在iOS13后，苹果限制voip推送使用，但不影响后台保活）；实现voip推送，然后后台默认播放铃声！
1. 选择后台模式
图片.png
2. 应用AVFoundation和<PushKit/PushKit.h>框架、定义属性
@property (nonatomic, strong) AVAudioPlayer *player;
@property (nonatomic,assign)UIBackgroundTaskIdentifier backgroundTaskIdentifier;
3. 后台铃声代码实现
- (AVAudioPlayer *)player{
if (!_player){
NSURL *url=[[NSBundle mainBundle]URLForResource:@"work5.mp3" withExtension:nil];
_player = [[AVAudioPlayer alloc]initWithContentsOfURL:url error:nil];
[_player prepareToPlay];
_player.volume = 0.00;
//一直循环播放
_player.numberOfLoops = -1;
[[AVAudioSession sharedInstance] setActive:YES error:nil];
[[AVAudioSession sharedInstance]setCategory:AVAudioSessionCategoryPlayback withOptions:AVAudioSessionCategoryOptionMixWithOthers error:nil];
}
return _player;
}
- (void)startBgTask{
UIApplication *application = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTask;
bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
//这里延迟的系统时间结束
[application endBackgroundTask:bgTask];
NSLog(@"%f",application.backgroundTimeRemaining);
}];
}
- (void)applicationDidEnterBackground:(UIApplication *)application{
[self startBgTask];
[self.player play];
}
4. voip代码实现（配置voip证书省略。。。。）
-(void)startVoIPPush{
NSString * identifier = [[NSBundle mainBundle] bundleIdentifier];
if ([identifier isEqualToString:@"com.eccalc.chat2u"] && [[UIDevice currentDevice].systemVersion floatValue] >= 8.0) {
//if([[UIDevice currentDevice].systemVersion floatValue] < 10)
{
PKPushRegistry * pushRegistry = [[PKPushRegistry alloc] initWithQueue:dispatch_get_main_queue()];
pushRegistry.delegate = self;
pushRegistry.desiredPushTypes = [NSSet setWithObject:PKPushTypeVoIP];
//}else{
// UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
// center.delegate = self;
// [center requestAuthorizationWithOptions:(UNAuthorizationOptionAlert + UNAuthorizationOptionSound)
// completionHandler:^(BOOL granted, NSError * _Nullable error) {
// // Enable or disable features based on authorization.
// }];
// [center getNotificationSettingsWithCompletionHandler:^(UNNotificationSettings * _Nonnull settings) {
// }];
}
// UIUserNotificationType types = (UIUserNotificationTypeBadge | UIUserNotificationTypeSound | UIUserNotificationTypeAlert);
// UIUserNotificationSettings * notificationSettings = [UIUserNotificationSettings settingsForTypes:types categories:nil];
// [[UIApplication sharedApplication]registerUserNotificationSettings:notificationSettings];
}else{
g_default removeObjectForKey:@"voipToken"];
}
}
#pragma mark - PKPushRegistryDelegate
-(void)pushRegistry:(PKPushRegistry *)registry didUpdatePushCredentials:(PKPushCredentials *)credentials forType:(PKPushType)type{
if ([credentials.token length] == 0) {
// MSULog(@"voip token NULL");
return;
}
NSString * voipToken;
if (@available(iOS 13.0, *)) {
voipToken = [self getHexStringForData:credentials.token];
}else {
voipToken = [[[[credentials.token description] stringByReplacingOccurrencesOfString:@"<" withString:@""] stringByReplacingOccurrencesOfString:@">" withString:@""] stringByReplacingOccurrencesOfString:@" " withString:@""];
}
//voipToken 需要提交给服务器
[g_default setObject:voipToken forKey:@"voipToken"];
// MSULog(@"voipToken:%@",voipToken);
}
#pragma mark - 但在iOS11.0之后，系统也提供了另外一个方法实现唤醒后的操作，此方法开启后，我项目iOS13以下机型会出现受收不到voip消息情况，所以注释了
//- (void)pushRegistry:(PKPushRegistry *)registry didReceiveIncomingPushWithPayload:(PKPushPayload *)payload forType:(PKPushType)type withCompletionHandler:(void (^)(void))completion
//{
// if (type != PKPushTypeVoIP) {
// return;
// }
// [self dealWithPushkitDidReceiveIncomingPushWithPayload:payload];
//}
#pragma mark - iOS8.0~iOS11.0是使用上面这个代理方法来实现唤醒后的操作，
-(void)pushRegistry:(PKPushRegistry *)registry didReceiveIncomingPushWithPayload:(PKPushPayload *)payload forType:(PKPushType)type{
if (type != PKPushTypeVoIP) {
return;
}
//此处写相关处理逻辑
//[self dealWithPushkitDidReceiveIncomingPushWithPayload:payload];
}