我有以下代码从我的网络服务器下载图像。
问题在于Android 2.2（只有2.2 - 在2.3中正常工作），实际上只有2个下载中的1个可用。每一次下载都不会读取任何内容。我已更新我的代码以进行检查，如果失败，请重试。重试工作正常，因此它与部分图像无关。
我的代码：
public int DownloadFromUrl(String imageURL, String fileName) {
int downloadlength=0;
try {
URL url = new URL(imageURL);
Log.d("ImageManager", "download from " + url + " to " + fileName);
URLConnection ucon = url.openConnection();
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is, 8192);
ByteArrayBuffer baf = new ByteArrayBuffer(128);
int current = 0;
while ((current = bis.read()) != -1) {
baf.append((byte) current);
}
downloadlength = baf.length();
if (downloadlength > 0) {
File file = new File(getFilesDir()+"/"+fileName);
Log.d("ImageManager", "file read, " + baf.length() + " bytes, will try storing in "+file);
FileOutputStream fos = new FileOutputStream(file);
fos.write(baf.toByteArray());
fos.close();
}
else {
Log.d("ImageManager", "nothing downloaded - not saving");
}
} catch (Exception e) {
Log.d("ImageManager", "Error: " + e);
}
return downloadlength;
}
private class DownloadImages extends AsyncTask<Integer, Integer, Integer> {
@Override
protected Integer doInBackground(Integer... pic_ids) {
int count = pic_ids.length;
for (int i=0; i < count; i++) {
// download the image from website ...
String url = "http://www.mysite.com/pic.php?hash=xyz&mode=M&pid="+pic_ids[i];
Log.d("DownloadImages", "("+i+") downloading url "+url);
int downloadlength = DownloadFromUrl(url,pic_ids[i]+".jpg");
if (downloadlength > 0) {
Log.d("DownloadImages", "("+i+") download finished & saved "+url);
}
else {
Log.d("DownloadImages", "donwload failed - retrying");
downloadlength = DownloadFromUrl(url,pic_ids[i]+".jpg");
if (downloadlength > 0) {
Log.d("DownloadImages", "worked fine now ...");
}
else {
Log.d("DownloadImages", "still not downloaded");
}
}
// this publishes in percent ...
//publishProgress ((int) (((i+1) / (float) count)*100));
// publish in number of files instead
publishProgress((int) (i+1));
}
return count;
}
}
LogCat只包含我的Log语句，没有错误。 如您所见，第一个文件下载得很好，第二个文件失败并且必须重试。工作正常。第三个文件和以下是相同的（每隔一次下载工作）。
07-29 09:40:54.062: INFO/global(13482): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
07-29 09:40:54.652: DEBUG/DownloadImages(13482): (0) downloading url http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892204
07-29 09:40:54.652: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892204 to 892204.jpg
07-29 09:40:55.342: INFO/ActivityManager(71): Displayed activity com.mydomain.app/.SyncOnce: 1923 ms (total 1923 ms)
07-29 09:40:58.822: DEBUG/dalvikvm(13482): GC_FOR_MALLOC freed 3761 objects / 408120 bytes in 59ms
07-29 09:41:00.332: DEBUG/ImageManager(13482): file read, 50817 bytes, will try storing in /data/data/com.mydomain.app/files/892204.jpg
07-29 09:41:00.332: DEBUG/DownloadImages(13482): (0) download finished & saved http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892204
07-29 09:41:00.362: DEBUG/DownloadImages(13482): (1) downloading url http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892203
07-29 09:41:00.392: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892203 to 892203.jpg
07-29 09:41:00.682: DEBUG/ImageManager(13482): nothing downloaded - not saving
07-29 09:41:00.682: DEBUG/DownloadImages(13482): donwload failed - retrying
07-29 09:41:00.692: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892203 to 892203.jpg
07-29 09:41:05.572: DEBUG/ImageManager(13482): file read, 50425 bytes, will try storing in /data/data/com.mydomain.app/files/892203.jpg
07-29 09:41:05.582: DEBUG/DownloadImages(13482): worked fine now ...
07-29 09:41:05.612: DEBUG/DownloadImages(13482): (2) downloading url http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892193
07-29 09:41:05.652: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892193 to 892193.jpg
07-29 09:41:05.852: DEBUG/ImageManager(13482): nothing downloaded - not saving
07-29 09:41:05.852: DEBUG/DownloadImages(13482): donwload failed - retrying
07-29 09:41:05.862: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892193 to 892193.jpg
07-29 09:41:09.382: DEBUG/dalvikvm(13482): GC_FOR_MALLOC freed 3269 objects / 552920 bytes in 45ms
07-29 09:41:17.682: DEBUG/dalvikvm(13482): GC_FOR_MALLOC freed 182 objects / 105440 bytes in 40ms
07-29 09:41:17.692: INFO/dalvikvm-heap(13482): Grow heap (frag case) to 3.607MB for 262160-byte allocation
07-29 09:41:17.852: DEBUG/dalvikvm(13482): GC_FOR_MALLOC freed 1 objects / 131096 bytes in 156ms
07-29 09:41:21.312: DEBUG/ImageManager(13482): file read, 169122 bytes, will try storing in /data/data/com.mydomain.app/files/892193.jpg
07-29 09:41:21.332: DEBUG/DownloadImages(13482): worked fine now ...
07-29 09:41:21.352: DEBUG/DownloadImages(13482): (3) downloading url http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892184
07-29 09:41:21.392: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892184 to 892184.jpg
07-29 09:41:21.552: DEBUG/ImageManager(13482): nothing downloaded - not saving
07-29 09:41:21.552: DEBUG/DownloadImages(13482): donwload failed - retrying
07-29 09:41:21.562: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892184 to 892184.jpg
07-29 09:41:25.782: DEBUG/ImageManager(13482): file read, 40484 bytes, will try storing in /data/data/com.mydomain.app/files/892184.jpg
07-29 09:41:25.782: DEBUG/DownloadImages(13482): worked fine now ...
07-29 09:41:25.832: DEBUG/DownloadImages(13482): (4) downloading url http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892182
07-29 09:41:25.852: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892182 to 892182.jpg
07-29 09:41:26.022: DEBUG/ImageManager(13482): nothing downloaded - not saving
07-29 09:41:26.022: DEBUG/DownloadImages(13482): donwload failed - retrying
07-29 09:41:26.032: DEBUG/ImageManager(13482): download from http://www.mysite.com/pic.php?hash=xyz&mode=M&pid=892182 to 892182.jpg
07-29 09:41:29.562: DEBUG/dalvikvm(13482): GC_FOR_MALLOC freed 2134 objects / 747720 bytes in 44ms
07-29 09:41:32.482: DEBUG/ImageManager(13482): file read, 69786 bytes, will try storing in /data/data/com.mydomain.app/files/892182.jpg
07-29 09:41:32.482: DEBUG/DownloadImages(13482): worked fine now ...
仅供参考，如果我拿出支票（如果下载长度> 0）重试，我最终只会下载文件1,3,5等......