NSMutableArray归零

Question

我使用以下方法创建一个NSMutableArray并向其中添加一些值：

NSMutableArray * pointsForInterpolation = [[NSMutableArray alloc] init];
//Code to add objects to array 

然后，我通过在分配和初始化数组的相同方法中执行以下操作，设置了一个与数组相等的属性：

self.wavePoints = pointsForInterpolation;

self.wavePoints是一个NSMutableArray属性，它很强(@property(nonatomic,strong) NSMutableArray *wavePoints;)。然后，我执行以下操作：

-(void) setWavePoints:(NSMutableArray *)wavePoints
{
    _wavePoints = wavePoints;
    NSLog(@"_wavePoints count %lu", [_wavePoints count]);
}

我的NSLog显示_wavePoints有一个有效的计数，并且不是nil。我继续执行其他一些与数组无关的方法，直到我到达最后一个方法：

- (UIBezierPath*) createPath 
{
    NSLog(@"Wave points count %lu", [_wavePoints count]);
    NSMutableArray* data = [self.wavePoints mutableCopy];
    NSLog(@"ARRay count 2 %lu", [data count]);
}

标题：

@interface OSWaveView ()

    @property(nonatomic,strong)AVAsset *audioAsset;
    @property(nonatomic,strong) NSMutableArray *wavePoints;
    @property (nonatomic, strong) NSMutableArray * pointsForInterpolation;
    @property(nonatomic,assign)CGFloat minAmpl;
    @property(nonatomic,assign)CGFloat maxAmpl;
    @property (nonatomic, strong) CAShapeLayer* blueWave;
    @property (nonatomic, strong) CAShapeLayer* redWave;

@end

最后两个NSLog显示的计数为零。我的初始数组(pointsForInterpolation)发布了吗？

Answer 1

-(void) setWavePoints:(NSMutableArray *)wavePoints {
    _wavePoints = wavePoints;
    NSLog(@"_wavePoints count %lu", [_wavePoints count]); 
}

My NSLog shows that _wavePoints has a valid count and is not nil. I go on to execute some other methods that have nothing to do with the array until I reach this last method:

- (UIBezierPath*) createPath 
{
    NSLog(@"Wave points count %lu", [_wavePoints count]);
    NSMutableArray* data = [self.wavePoints mutableCopy];
    NSLog(@"ARRay count 2 %lu", [data count]);
}

你的解释有点偏差。即使_wavePoints为零，您的日志也会返回0。您应该进行显式检查，以查看数组是否为nil。

如果NSLog(@"%@", self.wavePoints)被正确初始化，它应该返回nil/零以外的值。一旦确认了这一点，您就知道数组不是问题所在，而是没有向数组添加任何值，这会将问题指向for循环，并且与要置零的数组没有任何关系。