ios - 如何删除屏幕上绘制的图像并释放所有链接以便 ARC 回收？

Question

我有一个动画时钟，目前有内存泄漏。我目前似乎能够将东西放在图像之上，但不能将其取走或必须清除它(除了重新绘制整个时钟以使秒针不在两个不同的位置之外)。

用于清除时钟组件的代码是:

for(UIView *image in self.toWipe)
{
    [image removeFromSuperview];
}
[self.toWipe removeAllObjects];

绘制秒针(时分处理相同)的代码为:

CGAffineTransform secondTransform = CGAffineTransformMakeTranslation(centerX, centerY);
secondTransform = CGAffineTransformTranslate(secondTransform, -10, -189);
secondTransform = CGAffineTransformRotate(secondTransform, seconds / 60.0 * M_PI * 2.0);
UIImageView *secondHandView = [[UIImageView alloc] initWithImage:secondHandImage];
secondHandView.transform = secondTransform;
[self.view addSubview:secondHandView];
[self.toWipe addObject:secondHandView];
[self.toWipe addObject:secondHandImage];

我通过在每次迭代时绘制钟面来掩盖绘制的秒针不会自行删除；如果我不这样做，第二只手(或其他人)将扫出越来越大的馅饼，直到它们到达 360° 填充的圆盘。内存增长，缓慢但稳定，秒针的运动变得更加不稳定。

还有什么我可以或应该做的来让用过的元素被遗忘吗？我在这个项目中使用 ARC；我想知道我还能提供更多或不同的东西，以便修复内存泄漏。

谢谢，

--编辑--

以下是方法体，cruft 被注释掉，cruft 没有被注释掉。它不处理异常，并且主体中的任何内容都不会引发异常:

int height = floor([[UIScreen mainScreen] bounds].size.height + .4);
int width = floor([[UIScreen mainScreen] bounds].size.width + .4);
UIImage *backgroundImage = nil;

if (height == 2048 || height == 2008 || height == 1024 || height == 1004 || height == 984)
{
    if (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation))
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Portrait.png"];
    }
    else
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Landscape.png"];
    }
}
else if (height == 1536 || height == 768 || height == 748 || height == 728)
{
    backgroundImage = [UIImage imageNamed:@"Background-Default-Landscape.png"];
}
else if (height == 1136 || height == 1116 || height == 1096)
{
    if (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation))
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-568.png"];
    }
    else
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Rotated-568.png"];
    }
}
else if (height == 960 || height == 940 || height == 920 || height == 480 || height == 460 || height == 440)
{
    if (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation))
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default.png"];
    }
    else
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Rotated.png"];
    }
}
else if ((height == 640 || height == 620 || height == 600) && (width == 1136 || width == 1116 || width == 1096))
{
    backgroundImage = [UIImage imageNamed:@"Background-Rotated-568.png"];
}
else if ((height == 640 || height == 620 || height == 600 || height == 320 || height == 300 || height == 280) && (width == 960 || width == 940 || width == 920 || width == 480 || width == 470 || width == 410))
{
    if (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation))
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Portrait.png"];
    }
    else
    {
        backgroundImage = [UIImage imageNamed:@"Background-Default-Rotated.png"];
    }
}
else
{
    backgroundImage = [UIImage imageNamed:@"Background-Default-Portrait.png"];

}
backgroundImage = [UIImage imageNamed:@"Background-Default-Landscape.png"];


if (!UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation))
{
    int juggle = height;
    height = width;
    width = juggle;
}
NSUInteger centerX = width * .5;
NSUInteger centerY = height * .5;

CGRect containerRect = CGRectZero;
containerRect.size = [[UIScreen mainScreen] bounds].size;

for(UIView *image in self.toWipe)
{
    [image removeFromSuperview];
}
[self.toWipe removeAllObjects];
self.view.backgroundColor = [UIColor colorWithPatternImage:backgroundImage];
//     UIView *background = [UIImage imageNamed:@"Background-Default-Landscape.png"];
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:backgroundImage];
[self.view addSubview:backgroundView];
[self.toWipe addObject:backgroundView];
self.containerView = [[UIView alloc] initWithFrame:containerRect];
// float hours = 5.0;
// float minutes = 19.0;
// float seconds = 312.0;
// int timeStampMilliseconds = (ceil([[NSDate date] timeIntervalSince1970] * 1000.0));
// double timeStampMilliseconds = [[NSDate date] timeIntervalSince1970] * 1000.0;
double timeStampMilliseconds = CACurrentMediaTime() * 1000;
double hours = fmodf(timeStampMilliseconds, 86400000) / 3600000.0;
double minutes = fmodf(timeStampMilliseconds, 3600000) / 60000.0;
double seconds = fmodf(timeStampMilliseconds, 60000) / 1000.0;
// NSLog(@"Milliseconds: %lf, Hours: %lf, minutes: %lf, seconds: %lf", timeStampMilliseconds, hours, minutes, seconds);
[self.containerView removeFromSuperview];
self.containerView = [[UIView alloc] initWithFrame:containerRect];
UIImage *hourHandImage = [UIImage imageNamed:@"hour-hand.png"];
UIImageView *hourHandView = [[UIImageView alloc] initWithImage:hourHandImage];
hourHandImage = [UIImage imageNamed:@"hour-hand.png"];
hourHandView = [[UIImageView alloc] initWithImage:hourHandImage];
[self.view addSubview:hourHandView];

// UIImage *dotImage = [UIImage imageNamed:@"dot.png"];
// UIImageView *dotView = [[UIImageView alloc] initWithImage:dotImage];
// dotView.transform = CGAffineTransformMakeTranslation(centerX, centerY);
// [self.view addSubview:dotView];



hourHandView.layer.anchorPoint = CGPointMake(0.5f, 0.5f);
CGAffineTransform hourTransform = CGAffineTransformMakeTranslation(centerX, centerY);
    hourTransform = CGAffineTransformTranslate(hourTransform, -22, -122);
    hourTransform = CGAffineTransformRotate(hourTransform, hours / 12.0 * M_PI * 2.0);
    CGAffineTransform minuteTransform = CGAffineTransformMakeTranslation(centerX, centerY);
    minuteTransform = CGAffineTransformTranslate(minuteTransform, -10, -182);
    minuteTransform = CGAffineTransformRotate(minuteTransform, minutes / 60.0 * M_PI * 2.0);
    // hourTransform = CGAffineTransformTranslate(hourTransform, -sin(angle) * 50 + 122 , -cos(angle) * 50 + 122);


// hourTransform = CGAffineTransformTranslate(hourTransform, -330, 330);
hourHandView.transform = hourTransform;
[self.toWipe addObject:hourHandImage];
[self.toWipe addObject:hourHandView];
UIImage *minuteHandImage = [UIImage imageNamed:@"minute-hand.png"];
UIImageView *minuteHandView = [[UIImageView alloc] initWithImage:minuteHandImage];
minuteHandView.transform = minuteTransform;
[self.view addSubview:minuteHandView];
[self.toWipe addObject:minuteHandView];
[self.toWipe addObject:minuteHandImage];

minuteTransform = CGAffineTransformRotate(minuteTransform, minutes / 60.0 * M_PI * 2.0);
UIImage *secondHandImage = [UIImage imageNamed:@"second-hand.png"];
CGAffineTransform secondTransform = CGAffineTransformMakeTranslation(centerX, centerY);
secondTransform = CGAffineTransformTranslate(secondTransform, -10, -189);
secondTransform = CGAffineTransformRotate(secondTransform, seconds / 60.0 * M_PI * 2.0);
UIImageView *secondHandView = [[UIImageView alloc] initWithImage:secondHandImage];
secondHandView.transform = secondTransform;
[self.view addSubview:secondHandView];
[self.toWipe addObject:secondHandView];
[self.toWipe addObject:secondHandImage];



// hourHandView.layer.anchorPoint = CGPointMake(centerX, centerY);
// hourHandView.layer.affineTransform = CGAffineTransformRotate(transform, hour / (12.0 * M_PI * 2.0));
// UIImageView *minuteHandView = [[UIImageView alloc] initWithImage:minuteHandImage];
// UIImageView *secondHandView = [[UIImageView alloc] initWithImage:secondHandImage];

// [self.view addSubview:minuteHandView];
// [self.view addSubview:secondHandView];

Answer 1

您是否尝试过每秒都应用变换，而不是一遍又一遍地删除和添加 ImageView ？

这是我用于我正在开发的时钟应用程序的代码:

-(void)updateClock
{
    NSDateComponents *dateComponents = [[NSCalendar currentCalendar] components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:inDate];
    NSInteger seconds = [dateComponents second];
    NSInteger minutes = [dateComponents minute];
    NSInteger hours = [dateComponents hour];
    //NSLog(@"raw: hours:%d min:%d secs:%d", hours, minutes, seconds);
    if (hours > 12) hours -=12; //PM

    //set angles for each of the hands
    CGFloat secAngle = Degrees2Radians(seconds/60.0*360);
    CGFloat minAngle = Degrees2Radians(minutes/60.0*360);

    CGFloat minAdjustment = minAngle/12.0;
    CGFloat hourAngle = Degrees2Radians(hours/12.0*360) + minAdjustment;

    //reflect the rotations + 180 degres since CALayers coordinate system is inverted
    secHand.transform = CATransform3DMakeRotation (secAngle+M_PI, 0, 0, 1);
    minHand.transform = CATransform3DMakeRotation (minAngle+M_PI, 0, 0, 1);
    hourHand.transform = CATransform3DMakeRotation (hourAngle+M_PI, 0, 0, 1);
}