如何在上传到 Firebase 之前压缩图像？

Question

I am creating a social network application in which users can post images, so when a user uploads its image, it is of very large size and when I am retrieving that image, it is taking too much time with Picasso. Is there any way to compress those images before uploading without significant quality loss, so that they can be retrieved very efficiently and fast. PS: I am using Firebase as a backend Server.

Here is my code of uploading images.

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

    if(requestCode == Gallery_Pick && resultCode == RESULT_OK && data != null){
        ImageUri = data.getData();
        SelectPostImage.setImageURI(ImageUri);
    }
    super.onActivityResult(requestCode, resultCode, data);
}

final StorageReference filePath = PostImagesRef.child("Post Images").child(ImageUri.getLastPathSegment() + postRandomName + ".jpg");

    final UploadTask uploadTask = filePath.putFile(ImageUri);

    uploadTask.addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            String message = e.toString();
            Toast.makeText(PostActivity.this, "Some Error Occured"+message, Toast.LENGTH_SHORT).show();
            loadingBar.dismiss();
        }
    }).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
            Toast.makeText(PostActivity.this, "Image Uploaded Successfully", Toast.LENGTH_SHORT).show();
            Task<Uri> urlTask = uploadTask.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
                @Override
                public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
                    if(!task.isSuccessful()){
                        throw task.getException();
                    }
                    downloadImageUrl = filePath.getDownloadUrl().toString();

                    return filePath.getDownloadUrl();
                }
            }).addOnCompleteListener(new OnCompleteListener<Uri>() {
                @Override
                public void onComplete(@NonNull Task<Uri> task) {
                    if(task.isSuccessful()){

                        downloadImageUrl = task.getResult().toString();
                        Toast.makeText(PostActivity.this, "Saved To Database Successfully", Toast.LENGTH_SHORT).show();
                        SavingPostInformationToDatabase();

                    }
                }
            });
        }
    });

Please help me. Any Help or Suggestion Would Be Appreciable. Thanks In Advance.:! :)

Answer 1

You can simple using Glide to resize your image and using that image to upload to firebase

Glide.with(requireActivity())
                .asBitmap()
                .override(YOUR_IMAGE_SIZE, YOUR_IMAGE_SIZE)
                .load(uri)
                .into(object : CustomTarget<Bitmap>() {
                    override fun onResourceReady(
                        resource: Bitmap,
                        transition: Transition<in Bitmap>?
                    ) {

                        // using bitmapToByte(resource) -> byte
                        // using filePath.putBytes(data) -> uploadTask
                         val filePath = PostImagesRef.child("Post Images").child(ImageUri.getLastPathSegment() + postRandomName + ".jpg")

                         val uploadTask = filePath.putBytes(bitmapToByte(resource))
                    }

                    override fun onLoadCleared(placeholder: Drawable?) {
                        // this is called when imageView is cleared on lifecycle call or for
                        // some other reason.
                        // if you are referencing the bitmap somewhere else too other than this imageView
                        // clear it here as you can no longer have the bitmap
                    }
                })

bitmapToByte function

 fun bitmapToByte(bitmap: Bitmap): ByteArray {
    val stream = ByteArrayOutputStream()
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream)
    return stream.toByteArray()
}

hope this helps

Answer 2

You can try this way. Change this onActivityResult .

if(requestCode == Gallery_Pick && resultCode == RESULT_OK && data != null) {
            try {
                Uri imageUri = imageReturnedIntent.getData();
                InputStream imageStream = getContentResolver().openInputStream(imageUri);
                Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);

                selectedImage = getResizedBitmap(selectedImage, 400,300);// 400 and 300 height and width, replace with desired size

                imageView.setImageBitmap(selectedImage); // your desired image


            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

Here is the getResizedBitmap method you need.

    public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
    int width = bm.getWidth();
    int height = bm.getHeight();
    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;

    // create a matrix for the manipulation
    Matrix matrix = new Matrix();

    // resize the bit map
    matrix.postScale(scaleWidth, scaleHeight);

    // recreate the new Bitmap
    Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);

    return resizedBitmap;
}