SDWebImage类

Question

如何使用此方法在占位符中执行活动指示器？

- (void)createActivityIndicatorWithStyle:(UIActivityIndicatorViewStyle) activityStyle {

if ([self activityIndicator] == nil) {
    self.activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:activityStyle];

    self.activityIndicator.autoresizingMask = UIViewAutoresizingNone;

    //calculate the correct position
    float width = self.activityIndicator.frame.size.width;
    float height = self.activityIndicator.frame.size.height;
    float x = (self.frame.size.width / 2.0) - width/2;
    float y = (self.frame.size.height / 2.0) - height/2;
    self.activityIndicator.frame = CGRectMake(x, y, width, height);

    self.activityIndicator.hidesWhenStopped = YES;
    [self addSubview:self.activityIndicator];
}

[self.activityIndicator startAnimating];

}

感谢您的帮助

Answer 1

您可以这样做，我在本例中使用它来更新单元格，但它对于您需要的任何用途都是相同的。

我正在做的是将UIImageView alpha设置为0，添加一个UIActivityIndicatore，并调用一个块以在图像加载了bees时得到通知。加载时，UIImageView alpha将被设置回1，并删除UIActivityIndicator。

 -(void)updateCell {

 self.imageView = [[UIImageView alloc]initWithFrame:frameOfCell];
 self.imageView.alpha = 0;
[self addSubview:self.imageView];

//Activity indivator:
self.activity= [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
self.activity.hidesWhenStopped = YES;
self.activity.frame = CGRectMake((frameOfCell.size.width/2)-10, (frameOfCell.size.height/2)-20, 40, 40);
[self.activity startAnimating];
[self addSubview:self.activity];



[self.imageView setContentMode:UIViewContentModeScaleAspectFit];
NSURL *urlOfImage = [NSURL URLWithString:self.imageName];
self.imageView.alpha = 0;


[self.imageView setImageWithURL:urlOfImage completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
    ///
    self.imageView.alpha = 1;

    //Removing activity indicator:

    [self.activity stopAnimating];
    [self.activity removeFromSuperview];


}];

}

希望这能有所帮助

Answer 2

这是a Category on UIImageView, adding a progress view while images are downloaded using SDWebImage.

您应该做的是使用UIActivityIndicatorView更改UIProgressView

试着像这样修改代码：

- (void)removeIndicatorView{
   [self.activityIndicator stopAnimating];
}

- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options completed:(SDWebImageCompletedBlock)completedBlock withActivityStyle:(UIActivityIndicatorViewStyle) activityStyle {
    [self createActivityIndicatorWithStyle:activityStyle];

    __weak typeof(self) weakSelf = self;

    [self setImageWithURL:url
         placeholderImage:placeholder
                  options:options
                 progress:^(NSUInteger receivedSize, long long expectedSize) {
                     //If you don't care progress, do nothing
                 }
                completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
                    [weakSelf removeIndicatorView];
                    if (completedBlock) {
                        completedBlock(image, error, cacheType);
                    }
                }
     ];
}