带有自定义图像的活动指示器

I am loading a UIWebView and in the meantime I wan't to show a blank page with this activity indicator spinning (siri activity indicator). From what I have understand you can not change the image, but can't I use that image and create an animation with it rotating 360° and looping? Or will that drain the battery?

像这样的东西？：

- (void)webViewDidStartLoad:(UIWebView *)webView {
    //set up animation        
    [self.view addSubview:self.loadingImage];
    //start animation
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{   
    //stop animation
    [self.loadingImage removeFromSuperview];
}

我应该怎么办？

提前致谢！

其中大部分可以在 Stack Overflow 中找到。让我总结一下：

创建一个 UIImageView ，它将用作活动指示器（在故事板场景、NIB、代码......任何您想要的地方）。我们就这样称呼它吧_activityIndicatorImage

加载您的图像：_activityIndicatorImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"activity_indicator"]];

您需要使用动画来旋转它。这是我使用的方法：

+ (void)rotateLayerInfinite:(CALayer *)layer
{
    CABasicAnimation *rotation;
    rotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
    rotation.fromValue = [NSNumber numberWithFloat:0];
    rotation.toValue = [NSNumber numberWithFloat:(2 * M_PI)];
    rotation.duration = 0.7f; // Speed
    rotation.repeatCount = HUGE_VALF; // Repeat forever. Can be a finite number.
    [layer removeAllAnimations];
    [layer addAnimation:rotation forKey:@"Spin"];
}

在我的layoutSubviews方法中我启动旋转。你可以把它放在你的webViewDidStartLoad and webViewDidFinishLoad如果这更适合您的情况：

- (void)layoutSubviews
{
    [super layoutSubviews];

    // some other code 

    [Utils rotateLayerInfinite:_activityIndicatorImage.layer];
}

你总是可以使用停止旋转[_activityIndicatorImage.layer removeAllAnimations];