想要保持播放视图时播放声音

Question

我有一个用户移动一个对象，当移动结束时它将更新显示并播放声音。这一切都很好，但我不希望播放视图时播放声音。我如何避免这种情况发生？我需要在viewDidLoad中添加一些东西吗？这是触发事件的代码。谢谢你的帮助。 `

// Updates the text field with the current rotation angle and play sound. 
- (void) updateTextDisplay 
{ 
NSError *error = nil; 
if (imageAngle >=0 && imageAngle <=180){ 
    ComplimentPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"nice" ofType:@"m4a"]] error:&error]; 
    ComplimentPlayer.delegate = self; 
      textDisplay.text = [NSString stringWithFormat:@"blah blah blah"]; 
} else if (imageAngle >180 && imageAngle <=360){ 
    ComplimentPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] 
     pathForResource:@"good" ofType:@"m4a"]] error:&error]; 
    ComplimentPlayer.delegate = self; 
      textDisplay.text = [NSString stringWithFormat:@"blah blah"]; 
} 
NSTimeInterval playbackDelay = 0.5; 
[ComplimentPlayer playAtTime: ComplimentPlayer.deviceCurrentTime + playbackDelay]; 

} `

Answer 1

独立updateTextDisplay方法为两种方法

- (void) updateTextDisplay; 
- (void) playUpdateTextSound; 

别叫playUpdateTextSound（）当视图第一次加载。 并且在调用updateTextDisplay（）后调用playUpdateTextSound（）

Answer 2

编辑：难道整个视图重装或只是的UILabel？

设置一个int值，以检查视图第一次加载时的值，将值存储在用户默认值中，并在视图重新加载时更新值。然后在播放声音时在if逻辑中进一步比较。

在viewWillAppear中

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];//Add this or make it an ivar 
int a = 0; 
int b = ++a; //set int to add 1 to itself 
[defaults setInteger:b forKey:@"viewNumber"]; 
[[NSUserDefaults standardUserDefaults]synchronize]; 



    - (void) updateTextDisplay 
    { 
NSError *error = nil; 
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; //Add this or make it an ivar 
if (imageAngle >=0 && imageAngle <=180 && [defaults integerForKey@"viewNumber" >=2) //Add this here 
{ 
ComplimentPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:   [[NSBundle mainBundle] pathForResource:@"nice" ofType:@"m4a"]] error:&error]; 
ComplimentPlayer.delegate = self; 
     textDisplay.text = [NSString stringWithFormat:@"blah blah blah"]; 
    } else if (imageAngle >180 && imageAngle <=360 && [defaults integerForKey@"viewNumber">=2) //Add this here 
{ 
ComplimentPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath: [[NSBundle mainBundle] 
    pathForResource:@"good" ofType:@"m4a"]] error:&error]; 
ComplimentPlayer.delegate = self; 
     textDisplay.text = [NSString stringWithFormat:@"blah blah"]; 
} 
NSTimeInterval playbackDelay = 0.5; 
    [ComplimentPlayer playAtTime: ComplimentPlayer.deviceCurrentTime + playbackDelay]; 

在AppDelegate中添加

- (void)applicationWillTerminate:(UIApplication *)application 
{ 
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; 
[defaults setInteger:0 forKey:@"viewNumber"]; //this restores the value to 0 upon termination 
[[NSUserDefaults standardUserDefaults]synchronize]; 
    }