我正在使用
public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
如果我调用它并且CP无法提供该文件，则无论我在CP端执行什么操作，调用者（客户端）仍将获得空文件。也就是说，CP端文件提供程序（我在网络上检索文件）上的异常将永远不会传播到调用者，从而导致异常。这可以在API 14上解决吗？
代码看起来像这样：
ContentProvider:
@Override
public ParcelFileDescriptor openFile(Uri uri, String args) throws FileNotFoundException {
try {
return openPipeHelper(uri, "application/octet-stream", null, null, new FileDeliverer(uri, args)); //FileDeliverer constructor can cause MalformedURLException
} catch (IOException e) {
throw new FileNotFoundException("IOException when connecting!");
}
}
FileDeliverer类（实现ContentProvider.PipeDataWriter）具有以下覆盖方法：
@Override
public void writeDataToPipe(ParcelFileDescriptor clientSideParcelFileDescriptor, Uri uri, String s, Bundle bundle, Object o) {
InputStream inputStream;
ParcelFileDescriptor.AutoCloseOutputStream autoCloseOutputStream=null;
BasicHttpURLConnectorToTry basicHttpURLConnectorToTry =new BasicHttpURLConnectorToTry(url, timeOutMs);
try {
RepeatRetries repeatRetries = new RepeatRetries(basicHttpURLConnectorToTry, retries, retryDelayMs);
inputStream = (InputStream) repeatRetries.executeWithRetries();
autoCloseOutputStream=new ParcelFileDescriptor.AutoCloseOutputStream(clientSideParcelFileDescriptor);
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) != -1) {
autoCloseOutputStream.write(buffer, 0, len);
}
} catch (Exception e) {
Log.e("FileDeliverer", "Exception when connecting or delivering data to client!", e);
} finally {
basicHttpURLConnectorToTry.closeStreamAndDisconnect();
try {
autoCloseOutputStream.close();
} catch (Exception e) {
Log.w("FileDeliverer", "Couldn't close OutputStream!", e);
}
}
}