程序进入后台运行NSTimer

最新推荐文章于 2019-10-30 18:29:55 发布

转载最新推荐文章于 2019-10-30 18:29:55 发布 · 702 阅读

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#NSTimer #后台

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本文介绍如何在iOS应用中配置音频后台播放功能，包括修改info.plist文件、导入AVFoundation框架、设置AVAudioSession类别及激活状态等步骤。

1>转http://www.cnblogs.com/zzltjnh/archive/2013/05/15/3080058.html

2>info.plist - >Required background modes - > 添加App plays audio or streams audio/video using AirPlay

3>导入系统库 AVFoundation.framework

4>在AppDelegate.m中导入头文件 #import <AVFoundation/AVFoundation.h>

5>在- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{}中添加后台应用配置

（注：此处代码片只涉及配置）

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
   NSError *setCategoryErr = nil;
    NSError *activationErr  = nil;
    [[AVAudioSession sharedInstance]
     setCategory: AVAudioSessionCategoryPlayback
     error: &setCategoryErr];
    [[AVAudioSession sharedInstance]
     setActive: YES
     error: &activationErr];<pre name="code" class="objc">

6>在程序已经进入后台时进行如下操作

<pre name="code" class="objc">- (void)applicationDidEnterBackground:(UIApplication *)application {
    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;
            }
        });
    });
}

}