我的应用程序复制了一堆文件,请求以列表的形式出现。我有一个ContentProvider实现,所以我需要复制一个文件,并注册它与我的文件提供程序。我尝试了两件事-为每个文件副本剥离一个AsyncTask,并剥离一个AsyncTask来处理所有这些文件。我面临的问题是,与多个AsyncTasks手机真的减慢了一秒钟或两秒钟。然而,当一个一个地处理文件时,我得到IOException -文件描述符关闭:
D .doInBackground() - outputUri is /photo/20150602004304409
D .doInBackground() - outputUri is /photo/20150602004304421
D .doInBackground() - outputUri is /photo/20150602004304423
D .doInBackground() - outputUri is /photo/20150602004304426
D .doInBackground() - outputUri is /photo/20150602004304428
E java.io.IOException: File descriptor closed
E at libcore.io.Posix.writeBytes(Native Method)
E at libcore.io.Posix.write(Posix.java:223)
E at libcore.io.BlockGuardOs.write(BlockGuardOs.java:313)
E at libcore.io.IoBridge.write(IoBridge.java:497)
E at java.io.FileOutputStream.write(FileOutputStream.java:186)
这是我的代码:
Uri outputUri = Uri.parse(String.format(path, context.getPackageName()));
mOutputUri = context.getContentResolver().insert(outputUri, null);
if (AndroidHelper.isGingerBreadMR1()) {
execute();
} else {
executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
& lt;…>
InputStream inputStream = null;
OutputStream outputStream = null;
boolean error = false;
Log.d(TAG,".doInBackground() - outputUri is "+mOutputUri.getPath());
try {
inputStream = mContext.getContentResolver().openInputStream(mInputUri);
FileDescriptor fileDescriptor = getMediaFileDescriptor(mOutputUri);
if (fileDescriptor != null) {
outputStream = new FileOutputStream(fileDescriptor);
byte[] buffer = new byte[1024];
int read;
while ((read = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, read);
}
}
} catch (IOException e) {
Log.e(TAG, ".doInBackground - exception caught while copying the file",e);
error = true;
} finally {
try {
if (inputStream != null) {
inputStream.close();
}
if (outputStream != null) {
outputStream.close();
}
} catch (IOException e) {
Log.e(TAG, ".doInBackground - exception caught while closing input stream",e);
error = true;
}
}
return (error) ? mInputUri : mOutputUri;
getMediaFileDescriptor看起来像这样:
private FileDescriptor getMediaFileDescriptor(Uri outputUri) {
try {
return mContext.getContentResolver().openFileDescriptor(outputUri, "w")
.getFileDescriptor();
} catch (FileNotFoundException e) {
Log.e(TAG, ".getMediaFileDescriptor() - Error opening media output stream", e);
}
return null;
}
我有一些问题,它不是很好,但你必须在关闭它之前冲洗流。
while ((read = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, read);
outputStream.Flush();
}
我的问题解决了这个代码
您还应该确保在完成getContentResolver().openFileDescriptor
返回的ParcelFileDescriptor
时调用.close()