iOS App 后台保活
#import <AVFoundation/AVFoundation.h>
// --- 后台保活
@property(nonatomic, strong) AVAudioPlayer *backgroundPlayer;/**<播放器-后台音频*/
@property(nonatomic, assign) UIBackgroundTaskIdentifier taskID;/**<后台任务ID*/
#pragma mark - Life_Cycle
- (void)dealloc {
// 后台保活 - 删除观察者
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
#pragma mark -后台保活
- (void)keepAppLiveBackground {
[self addNotiAddObserver];
[self keepLiveByPlayMusic];
[self testKeepLiveTimer];
}
- (void)keepLiveByPlayMusic {
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setActive:YES error:nil];
[session setCategory:AVAudioSessionCategoryPlayback error:nil];
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
[self.backgroundPlayer play];
}
- (AVAudioPlayer *)backgroundPlayer {
if(_backgroundPlayer) {
NSURL *url = [[NSBundle mainBundle] URLForResource:@"DefaultMusicHighdown.mp3" withExtension:nil];
_backgroundPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];
[_backgroundPlayer prepareToPlay]; //异步预加载缓存
_backgroundPlayer.numberOfLoops = -1; // 无限循环
_backgroundPlayer.volume = 0.0; // 音量
}
return _backgroundPlayer;
}
- (void)addNotiAddObserver {
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(whenAppDidBackgroundWithNoti:)
name:UIApplicationDidEnterBackgroundNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(whenWillEnterForegroundWithNoti:)
name:UIApplicationWillEnterForegroundNotification
object:nil];
}
- (void)whenAppDidBackgroundWithNoti:(NSNotification *)noti {
if([noti.object isKindOfClass:[UIApplication class]]) {
NSLog(@"通知 : App 已进入后台");
[self.backgroundPlayer play];
UIApplication * app = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTask;
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
bgTask = UIBackgroundTaskInvalid;
}
});
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
bgTask = UIBackgroundTaskInvalid;
}
});
});
self.taskID = bgTask;
}
}
- (void)whenWillEnterForegroundWithNoti:(NSNotification *)noti {
if([noti.object isKindOfClass:[UIApplication class]]) {
NSLog(@"通知 : App 已进入前台");
[self.backgroundPlayer stop];
//
[[UIApplication sharedApplication] endBackgroundTask:self.taskID];
//
}
}
- (void)testKeepLiveTimer {
__block NSInteger count = 0;
[NSTimer scheduledTimerWithTimeInterval:3.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
NSLog(@"count:%li", count += 3);
}];
}
