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iOS

Nicolas Acosta
Nicolas Acosta
1,587 Points
Posted by Nicolas Acosta
Nicolas Acosta
1,587 Points

I need help with some help with an iOS issue please.

I'm on the 'Build a Simple iPhone App' of the iOS Development track.

Here's the link to a screenshot of my Xcode project: https://www.dropbox.com/s/okgx01pxosupc6q/Captura%20de%20pantalla%202014-08-02%2002.03.36.png

In the makePredtion function (Prediction pragma Mark), I want say something like:

_ The text disappears DONE

 self.predictionLabel.text = @" ";

_ The animation DONE

 [self.backgroundImageView startAnimating];

_ When the animation finished, make the prediction. I DON'T KONW IF IT'S OK

 if (self.backgroundImageView animationDidStop:????????????? finished:YES) {
 self.predictionLabel.text = [self.crystalBall randomPrediction];
 }

I need help with the last one

1 Answer

Pierre Thalamy
Pierre Thalamy
4,494 Points
Pierre Thalamy
Pierre Thalamy
4,494 Points

I don't think you can use animationDidStop for this, or at least, not as easily as you want to. If I got you right, what you want to do is:

  1. Hide the label
  2. Animate the UIImageView
  3. Only once the animation is over, have the label's text to reappear.

Here is another way, to do this:

- (void) makePrediction
{
    // Animate the UIImageView
    [self.backgroundImageView startAnimating];
    // Animate the view over 1 second (you may need to tweak the timing to match your needs)    
    [UIView animateWithDuration:1.0f animations:^{
       // Slowly fade out the label 
       self.predictionLabel.alpha = 0;
    } completion:^(BOOL finished){
    // Once fading is over:    
    [UIView animateWithDuration:1.0f animations:^{
            // Update the label's text
            self.predictionLabel.text = [self.crystalBall randomPrediction];   
            // Slowly fade in the label
            self.predictionLabel.alpha = 1;
        }];
    }];
}

The animateWithDuration method will perform the tasks enclosed inside the block with the symbols ^{...} gradually, over the period of time specified as argument. Here it is used to get a nice fading effect.

Let me know if you have any questions.