ios - ARC 和释放应用程序中的内存

Question

- (void)viewDidLoad
{

    [super viewDidLoad];

    self.predictionsObjectArray = [[AAPredictions alloc] init];

    [self.predictionsObjectArray setPredictionsArray:@[@"Probably Not", @"Ask Again", @"I doubt it", @"Unlikely", @"I believe so"]];



    for (int x = 1; x<61; x++) {
        NSMutableString *imageName = [[NSMutableString alloc] init];
        if (x > 9) {
            imageName = [NSMutableString stringWithFormat:@"CB000%i.png", x];
        }
        else {
           imageName = [NSMutableString stringWithFormat:@"CB0000%i.png", x];
        }

        [self.animationImagesArray addObject:[UIImage imageNamed:imageName]];

    }

}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark Prediction

-(void)makePrediction {
    self.predictionLabel.text = [self.predictionsObjectArray getPrediction];
    [self animateItems];


}
-(void)animateItems {

    self.image_button.alpha = 0.0;

    self.background_image.animationRepeatCount = 1.0;

    self.background_image.animationImages = self.animationImagesArray;

    self.background_image.animationDuration = 3.0;
    [self.background_image startAnimating];






    while (self.background_image.isAnimating) {

    }

    self.image_button.alpha = 1.0;

}

制作一个简单的 Crystal 球应用程序，并尝试为其制作动画。我确实已经为此工作了一段时间但没有运气。希望有人能在我学习时帮助我，特别是 ARC。我知道我需要在 viewDidLoad 中添加一行函数将引用计数添加到 self.animationImagesArray 的+1 ，因为当我去分配 self.background_image.animationImages至self.animationImagesArray ，ARC发布了它，我知道，因为在底部的调试器中，它的值为nil。任何帮助都会很棒。

Answer 1

格雷迪是正确的。您从未初始化数组。如果你没有像他发布的那样的初始化(对于非常新的人来说可能会造成混淆)就这样做:

//NEW: Initialize the array before adding items to it
self.animationImagesArray = [NSMutableArray new];

for (int x = 1; x<61; x++) {
    NSMutableString *imageName = [[NSMutableString alloc] init];
    if (x > 9) {
        imageName = [NSMutableString stringWithFormat:@"CB000%i.png", x];
    }
    else {
        imageName = [NSMutableString stringWithFormat:@"CB0000%i.png", x];
    }

    [self.animationImagesArray addObject:[UIImage imageNamed:imageName]];

}