iOS的背景音乐问题 [英] iOS background music problems

问题描述

  

可能重复：结果
  <一href=\"http://stackoverflow.com/questions/8467533/ios-sdk-playing-music-on-the-background-and-switching-views\">iOS SDK：打在背景音乐和切换视图

大家好即时通讯目前正在使用此code在我的应用程序来播放背景音乐时，其推出的。但是当我切换视图我SecondView并返回到我的firstView音乐开始了和重复当前播放的音乐它不断重复的音乐，当我返回到我的firstView，当我从SecondView切换回我的firstView我怎么能有音乐开始了。

FirstViewController.m

   - （无效）viewDidLoad中{
  * NSString的路径= [[一个NSBundle mainBundle] pathForResource：@鼓ofType：@MP3];
  theAudio = [[AVAudioPlayer页头] initWithContentsOfURL：[NSURL fileURLWithPathath]错误：NULL];
  theAudio.delegate =自我;
  theAudio.numberOfLoops = -1;
  [theAudio玩]
 

解决方案

您可以使用NSUserDefaults的保存音乐播放状态，因此该视图加载时，音乐将只如果它有没有玩过。

 如果（[[NSUserDefaults的standardUserDefaults] stringForKey：@乐] ==无）{
    * NSString的路径= [[一个NSBundle mainBundle] pathForResource：@鼓ofType：@MP3];
    theAudio = [[AVAudioPlayer页头] initWithContentsOfURL：[NSURL fileURLWithPathath]错误：NULL];
    theAudio.delegate =自我;
    theAudio.numberOfLoops = -1;
    [theAudio玩]
    [NSUserDefaults的standardUserDefaults]的setObject：@ - forKey：@音乐]; }
 

您必须退出应用程序时，重置回此键为零。否则，如果玩家退出应用程序，该应用程序已重新启动@音乐下一次串不会是零。

转到 projectAppDelegate.m 文件：

   - （无效）applicationDidEnterBackground：（UIApplication的*）{应用
        [NSUserDefaults的standardUserDefaults]的setObject：无forKey：@音乐]; }
 

如果音乐正在整个应用程序打，然后把音乐播放codeS，如下图所示是安全的。不要忘了申报AVAudioPlayer * theAudio在projectAppDelegate.h文件。

   - （无效）applicationDidBecomeActive：（UIApplication的*）{应用
    * NSString的路径= [[一个NSBundle mainBundle] pathForResource：@鼓ofType：@MP3];
    theAudio = [[AVAudioPlayer页头] initWithContentsOfURL：[NSURL fileURLWithPathath]错误：NULL];
    theAudio.delegate =自我;
    theAudio.numberOfLoops = -1;
    [theAudio玩]
    [NSUserDefaults的standardUserDefaults]的setObject：@ - forKey：@音乐]; }
 

我可能会在这里错过了一些位。只要运行一些测试，使其你喜欢的工作方式。我只是想在我的应用程序，它为我工作。

Possible Duplicate:
iOS SDK : playing music on the background and switching views

Hi guys im currently using this code to play background music in my app when its launched .But when i switch views to my SecondView and return back to my Firstview the music starts over and overlaps the music that is currently playing and it keeps overlapping music when i return back to my Firstview, how can i have the music start over when i switch back to my Firstview from my SecondView.

FirstViewController.m

- (void)viewDidLoad {
  NSString *path = [[NSBundle mainBundle] pathForResource:@"drums" ofType:@"mp3"];
  theAudio=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPathath] error:NULL];
  theAudio.delegate = self;
  theAudio.numberOfLoops = -1;
  [theAudio play]; 

解决方案

You can use NSUserDefaults to save the music playing status, so when the view is loaded, the music will only be played if it hasn't already.

 if ([[NSUserDefaults standardUserDefaults] stringForKey:@"music"] == nil) {
    NSString *path = [[NSBundle mainBundle] pathForResource:@"drums" ofType:@"mp3"];
    theAudio=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPathath] error:NULL];
    theAudio.delegate = self;
    theAudio.numberOfLoops = -1;
    [theAudio play]; 
    [[NSUserDefaults standardUserDefaults] setObject:@"-" forKey:@"music"]; }

You need to reset this key back to nil when quitting the app. Otherwise, if the player quit the app, and next time when the app is restarted the @"music" string wouldn't be nil.

Go to the projectAppDelegate.m file:

- (void)applicationDidEnterBackground:(UIApplication *)application {
        [[NSUserDefaults standardUserDefaults] setObject:nil forKey:@"music"]; }

If the music is being played throughout the app, then put the music playing codes as shown below to be safe. Don't forget to declare the AVAudioPlayer *theAudio in projectAppDelegate.h file.

- (void)applicationDidBecomeActive:(UIApplication *)application {
    NSString *path = [[NSBundle mainBundle] pathForResource:@"drums" ofType:@"mp3"];
    theAudio=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPathath] error:NULL];
    theAudio.delegate = self;
    theAudio.numberOfLoops = -1;
    [theAudio play]; 
    [[NSUserDefaults standardUserDefaults] setObject:@"-" forKey:@"music"]; }

I might have missed a few bits here. Just run a few tests to make it the way you like to work. I just tried on my app and it worked for me.

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