前言
一般APP在按下Home键被挂起后,这时APP的 backgroundTimeRemaining 也就是后台运行时间大约只有3分钟,如果在退出APP后,过十几二十二分钟或者更长时间再回到APP,APP就会回到刚打开时的状态,也就是首页;有的项目在被挂起后需要在后台运行一段时间,使有足够的时间来完成与服务器对接的操作,或者需要一直运行的需求;如果需要,则在APP被挂起后,申请后台,来延长后台运行时间。
APP申请后台运行的方式有几种:
播放音乐
定位
Newsstand downloads
fetch 等;
这里主要说下后台播放无声音乐(其实是不播放),采用哪种方式,对应勾选上图;我的项目中有音频播放需求,如果没有,那就找一个播放音频的理由,或者用其他方式实现。
实现
这里采用了两个单例:电话监控(XKTelManager)、后台运行(XKBGRunManager),电话监控可以忽略,视情况而用;采用单例是为了方便管理;
XKTelManager.h
#import <Foundation/Foundation.h> @interface XKTelManager : NSObject ///是否在后台运行 @property (nonatomic,assign) BOOL inBackgroundRun; + (XKTelManager *)sharedManager; /** 来电监听 */ - (void)startMonitor; @end
XKTelManager.m
#import "XKTelManager.h" #import "XKBGRunManager.h" #import <CoreTelephony/CTCallCenter.h> #import <CoreTelephony/CTCall.h> static XKTelManager *_sharedManger; @interface XKTelManager() @property (nonatomic, strong) CTCallCenter *callCenter; @end @implementation XKTelManager + (XKTelManager *)sharedManager{ static dispatch_once_t onceTelSingle; dispatch_once(&onceTelSingle, ^{ if (!_sharedManger) { _sharedManger = [[XKTelManager alloc]init]; } }); return _sharedManger; } - (instancetype)init{ self = [super init]; if (self) { _inBackgroundRun = NO; } return self; } #pragma mark -********* 监听电话相关 - (void)startMonitor { __weak typeof(self) weakSelf = self; _callCenter = [[CTCallCenter alloc] init]; _callCenter.callEventHandler = ^(CTCall * call) { ///如果已经进入后台了,不做任何操作 if (weakSelf.inBackgroundRun) { return; } ///APP未进入后台 if ([call.callState isEqualToString:CTCallStateDisconnected]){ NSLog(@"电话 --- 断开连接"); [[XKBGRunManager sharedManager] stopBGRun]; } else if ([call.callState isEqualToString:CTCallStateConnected]){ NSLog(@"电话 --- 接通"); } else if ([call.callState isEqualToString:CTCallStateIncoming]){ NSLog(@"电话 --- 待接通"); [[XKBGRunManager sharedManager] startBGRun]; } else if ([call.callState isEqualToString:CTCallStateDialing]){ NSLog(@"电话 --- 拨号中"); [[XKBGRunManager sharedManager] startBGRun]; } else { NSLog(@"电话 --- 无操作"); } }; } @end
XKBGRunManager.h
#import <Foundation/Foundation.h> @interface XKBGRunManager : NSObject + (XKBGRunManager *)sharedManager; /** 开启后台运行 */ - (void)startBGRun; /** 关闭后台运行 */ - (void)stopBGRun; @end
XKBGRunManager.m
#import "XKBGRunManager.h" ///循环时间 static NSInteger _circulaDuration = 60; static XKBGRunManager *_sharedManger; @interface XKBGRunManager() @property (nonatomic,assign) UIBackgroundTaskIdentifier task; ///后台播放 @property (nonatomic,strong) AVAudioPlayer *playerBack; @property (nonatomic, strong) NSTimer *timerAD; ///用来打印测试 @property (nonatomic, strong) NSTimer *timerLog; @property (nonatomic,assign) NSInteger count; @end @implementation XKBGRunManager{ CFRunLoopRef _runloopRef; dispatch_queue_t _queue; } + (XKBGRunManager *)sharedManager{ static dispatch_once_t onceRunSingle; dispatch_once(&onceRunSingle, ^{ if (!_sharedManger) { _sharedManger = [[XKBGRunManager alloc]ini