Question

I’m having some trouble figuring out hot to update a UILabel twice in one action. Basically the user hits a play button to hear a sound. While the sound is playing “message 1” appears in the UILabel. When the sound is done playing “Message 2” appears in the same label. When I run this the label goes directly to “message 2”.

.h

@interface ViewController : UIViewController
<AVAudioRecorderDelegate, AVAudioPlayerDelegate>
{
AVAudioPlayer *audioPlayer;
UIButton *playButton;
UILabel *answerLabel;

}
@property (nonatomic, retain) IBOutlet UIButton *playButton;
@property (nonatomic, retain) IBOutlet UILabel *answerLabel;
-(IBAction) play;
@end

.m

-(IBAction) play
{    
        int length = [audioPlayer duration];
        [audioPlayer play];
        answerLabel.text = @"Message 1";
        [NSThread sleepForTimeInterval:length];
        answerLabel.text = @"Message 2";   
}

Answer 1

I see you implement the AVAudioPlayerDelegate protocol, so I assume that at some point you set the delegate of the player to self

If that is the case, change your play method to the following:

-(IBAction) play
{    
    [audioPlayer play];
    answerLabel.text = @"Message 1";
}

Then implement this method:

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
    answerLabel.text = @"Message 2";
}