SDWebImage 类

Posted 2023-03-08

【中文标题】SDWebImage 类

【英文标题】：SDWebImage Class

【发布时间】：2014-03-07 08:53:04

【问题描述】：

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];

感谢任何帮助

【问题讨论】：

你把指标放在哪里？是 UIImageView 吗？

是的，我需要这样做并将指示器放在 UIImageView 占位符中

需要修改SDWebImage的开源，可以接受吗？

是的，我接受，你能帮忙吗？

【参考方案1】：

你可以这样做，我在这个例子中使用它来更新单元格，但对于你需要的任何用途都是一样的。

我正在做的是将 UIImageView alpha 设置为 0，添加 UIActivityIndi​​catore，并在加载图像时调用一个块来获得通知。 加载后，UIImageView alpha 将被设置回 1，并删除 UIActivityIndi​​cator。

 -(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];


];

希望对你有帮助

【参考方案2】：

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

你应该做的是将UIProgressView更改为UIActivityIndicatorView

尝试像这样修改代码：

- (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);
                    
                
     ];