在NetworkImageView- Volley

Question

我正在尝试在我的应用程序中的Volley类的NetworkImageView中禁用缓存。我尝试了这段代码，但它没有删除缓存。

mNetworkImageView = (NetworkImageView) getView().findViewById(R.id.networkImageView);
mImageLoader = VolleySingleton.getInstance().getImageLoader();
mNetworkImageView.setImageUrl(IMAGE_URL, mImageLoader);
VolleySingleton.getInstance().getRequestQueue().getCache().remove(IMAGE_URL);

Answer 1

您可以尝试以下内容（在VolleySingleton类内）：

    mImageLoader = new ImageLoader(mRequestQueue, new ImageLoader.ImageCache() {
        @Override
        public Bitmap getBitmap(String url) {
            return null;
        }

        @Override
        public void putBitmap(String url, Bitmap bitmap) {
        }
    });

您可以检查调试时间，在Bitmap cachedBitmap = mCache.getBitmap(cacheKey);内的ImageLoader.java行设置断点，您会发现cachedBitmap为空。

或者将Log.w("cachedBitmap", "Bitmap cached!");作为我的以下代码进行检查：

public ImageContainer get(String requestUrl, ImageListener imageListener,
        int maxWidth, int maxHeight, ScaleType scaleType) {

    // only fulfill requests that were initiated from the main thread.
    throwIfNotOnMainThread();

    final String cacheKey = getCacheKey(requestUrl, maxWidth, maxHeight, scaleType);

    // Try to look up the request in the cache of remote images.
    Bitmap cachedBitmap = mCache.getBitmap(cacheKey);
    if (cachedBitmap != null) {
        Log.w("cachedBitmap", "Bitmap cached!");
        // Return the cached bitmap.
        ImageContainer container = new ImageContainer(cachedBitmap, requestUrl, null, null);
        imageListener.onResponse(container, true);
        return container;
    }

    // The bitmap did not exist in the cache, fetch it!
    ImageContainer imageContainer =
            new ImageContainer(null, requestUrl, cacheKey, imageListener);

    // Update the caller to let them know that they should use the default bitmap.
    imageListener.onResponse(imageContainer, true);

    // Check to see if a request is already in-flight.
    BatchedImageRequest request = mInFlightRequests.get(cacheKey);
    if (request != null) {
        // If it is, add this request to the list of listeners.
        request.addContainer(imageContainer);
        return imageContainer;
    }

    // The request is not already in flight. Send the new request to the network and
    // track it.
    Request<Bitmap> newRequest = makeImageRequest(requestUrl, maxWidth, maxHeight, scaleType,
            cacheKey);

    mRequestQueue.add(newRequest);
    mInFlightRequests.put(cacheKey,
            new BatchedImageRequest(newRequest, imageContainer));
    return imageContainer;
}

希望它有所帮助！

Answer 2

Google Volley提供了两种方法来清除缓存中的项目：

AppController.getInstance().getRequestQueue().getCache().remove(key);

和

AppController.getInstance().getRequestQueue().getCache().invalidate(key, fullExpire);

remove（）表示您要删除实际的缓存数据。

invalidate（）表示您只是将数据标记为无效。因此，凌空将检查服务器数据是否仍然有效。完全过期确定是否在凌空使用服务器验证数据之前使用数据。

要在每30分钟清除缓存，请使用以下代码： -

您可以使用凌空的serverDate 来获取最初收到回复的日期

AppController.getInstance().getRequestQueue().getCache().get(url).serverDate

因此在您的代码中使用getMinutesDifference函数作为

public static long getMinutesDifference(long timeStart,long timeStop){
        long diff = timeStop - timeStart;
        long diffMinutes = diff / (60 * 1000);

        return  diffMinutes;
 }

将该功能称为

Calendar calendar = Calendar.getInstance();
long serverDate = AppController.getInstance().getRequestQueue().getCache().get(url).serverDate;
if(getMinutesDifference(serverDate, calendar.getTimeInMillis()) >=30){
   AppController.getInstance().getRequestQueue().getCache().invalidate(url, true);
}

如果之前的网址响应＆gt; = 30分钟，它将使缓存无效。

希望它有所帮助！