Firebase云存储中的Android访问文件仍处于离线状态

Question

I need to show images taken by the user in my application. I storing them in FirebaseFirestore with the following code:

StorageReference imagesRef = storage.getReference("images/"+device.ref+"/"+timeStamp+".png");

Bitmap bitmap = BitmapFactory.decodeFile(output.toString());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] image = baos.toByteArray();

UploadTask uploadTask = imagesRef.putBytes(image);
uploadTask.addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
    }
});

This works well, and when I am offline and I then go online the files nicely auto upload to Storage .

However even when offline I still need to be able to access this image. I am accessing the image normally with the following code:

FirebaseStorage storage = FirebaseStorage.getInstance();
StorageReference storageReference = storage.getReference().child("images/"+device+"/"+image.getFilename());

try {
    File localFile = File.createTempFile("images", "jpg");
    localFile.deleteOnExit();

    storageReference.getFile(localFile).addOnSuccessListener(new OnSuccessListener<FileDownloadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(FileDownloadTask.TaskSnapshot taskSnapshot) {
            Log.v("Download", "downloaded");
        }
    }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception exception) {
            // Handle any errors
        }
    });
} catch (IOException e) {
    e.printStackTrace();
}

However if I 'upload' am image whilst offline I can't seem to get it back, is there a reason for this, or perhaps a work around? Suggestions much appreciated.

Answer 1

Cloud Storage for Firebase doesn't have an "offline" mode for dealing with files. It's not like Realtime Database and Firestore. You can only download a file while online, and you can't download a file that hasn't finished uploading while online. If you need to deal with files while offline, you should do that with your own local cache.