Question

我让用户移动一个对象，当移动结束时，它将更新显示并播放声音。这一切都很好，但我不想在视图首次加载时播放声音。我如何防止这种情况发生？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

编辑：整个视图是重新加载还是只是UILabel？

设置一个int值以检查视图首次加载时，将值存储在用户默认值中，并在视图重新加载时更新该值。然后在播放声音时使用if逻辑进行进一步比较。

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];
  }

Answer 2

将updateTextDisplay方法分成两个方法

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

首次加载视图时不要调用playUpdateTextSound（）。并在调用updateTextDisplay（）

之后调用playUpdateTextSound（）

想要在视图加载时保持声音不被播放

2 个答案: