Firebase Storage Operations

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CODE_PICK_IMAGE = 1;
    private static final int PERMISSION_READ_WRITE_EXTERNAL_STORAGE = 2;

    private FirebaseStorage mFirebaseStorage;
    private StorageReference mStorageReference;
    private StorageReference mStorageReferenceImages;
    private Uri mUri;
    private ImageView mImageView;
    private ProgressDialog mProgressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        mImageView = (ImageView) findViewById(R.id.imageView);
        setSupportActionBar(toolbar);

        // Create an instance of Firebase Storage
        mFirebaseStorage = FirebaseStorage.getInstance();
    }

    private void pickImage() {
        Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        startActivityForResult(intent, REQUEST_CODE_PICK_IMAGE);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            if (requestCode == REQUEST_CODE_PICK_IMAGE) {
                String filePath = FileUtil.getPath(this, data.getData());
                mUri = Uri.fromFile(new File(filePath));
                uploadFile(mUri);
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == PERMISSION_READ_WRITE_EXTERNAL_STORAGE) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                pickImage();
            }
        }
    }

    private void showProgressDialog(String title, String message) {
        if (mProgressDialog != null && mProgressDialog.isShowing())
            mProgressDialog.setMessage(message);
        else
            mProgressDialog = ProgressDialog.show(this, title, message, true, false);
    }

    private void hideProgressDialog() {
        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.dismiss();
        }
    }

    private void showToast(String message) {
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
    }

    public void showHorizontalProgressDialog(String title, String body) {

        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.setTitle(title);
            mProgressDialog.setMessage(body);
        } else {
            mProgressDialog = new ProgressDialog(this);
            mProgressDialog.setTitle(title);
            mProgressDialog.setMessage(body);
            mProgressDialog.setIndeterminate(false);
            mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            mProgressDialog.setProgress(0);
            mProgressDialog.setMax(100);
            mProgressDialog.setCancelable(false);
            mProgressDialog.show();
        }
    }

    public void updateProgress(int progress) {
        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.setProgress(progress);
        }
    }

    /**
     * Step 1: Create a Storage
     *
     * @param view
     */
    public void onCreateReferenceClick(View view) {
        mStorageReference = mFirebaseStorage.getReferenceFromUrl("gs://**something**.appspot.com");
        showToast("Reference Created Successfully.");
        findViewById(R.id.button_step_2).setEnabled(true);
    }

    /**
     * Step 2: Create a directory named "Images"
     *
     * @param view
     */
    public void onCreateDirectoryClick(View view) {
        mStorageReferenceImages = mStorageReference.child("images");
        showToast("Directory 'images' created Successfully.");
        findViewById(R.id.button_step_3).setEnabled(true);
    }

    /**
     * Step 3: Upload an Image File and display it on ImageView
     *
     * @param view
     */
    public void onUploadFileClick(View view) {
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED || ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_READ_WRITE_EXTERNAL_STORAGE);
        else {
            pickImage();
        }
    }

    /**
     * Step 4: Download an Image File and display it on ImageView
     *
     * @param view
     */
    public void onDownloadFileClick(View view) {
        downloadFile(mUri);
    }

    /**
     * Step 5: Delete am Image File and remove Image from ImageView
     *
     * @param view
     */
    public void onDeleteFileClick(View view) {
        deleteFile(mUri);
    }

    private void showAlertDialog(Context ctx, String title, String body, DialogInterface.OnClickListener okListener) {

        if (okListener == null) {
            okListener = new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            };
        }

        AlertDialog.Builder builder = new AlertDialog.Builder(ctx).setMessage(body).setPositiveButton("OK", okListener).setCancelable(false);

        if (!TextUtils.isEmpty(title)) {
            builder.setTitle(title);
        }

        builder.show();
    }

    private void uploadFile(Uri uri) {
        mImageView.setImageResource(R.drawable.placeholder_image);

        StorageReference uploadStorageReference = mStorageReferenceImages.child(uri.getLastPathSegment());
        final UploadTask uploadTask = uploadStorageReference.putFile(uri);
        showHorizontalProgressDialog("Uploading", "Please wait...");
        uploadTask
                .addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                    @Override
                    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                        hideProgressDialog();
                        Uri downloadUrl = taskSnapshot.getDownloadUrl();
                        Log.d("MainActivity", downloadUrl.toString());
                        showAlertDialog(MainActivity.this, "Upload Complete", downloadUrl.toString(), new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                findViewById(R.id.button_step_3).setEnabled(false);
                                findViewById(R.id.button_step_4).setEnabled(true);
                            }
                        });

                        Glide.with(MainActivity.this)
                                .load(downloadUrl)
                                .into(mImageView);
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception exception) {
                        exception.printStackTrace();
                        // Handle unsuccessful uploads
                        hideProgressDialog();
                    }
                })
                .addOnProgressListener(MainActivity.this, new OnProgressListener<UploadTask.TaskSnapshot>() {
                    @Override
                    public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
                        int progress = (int) (100 * (float) taskSnapshot.getBytesTransferred() / taskSnapshot.getTotalByteCount());
                        Log.i("Progress", progress + "");
                        updateProgress(progress);
                    }
                });
    }

    private void downloadFile(Uri uri) {
        mImageView.setImageResource(R.drawable.placeholder_image);
        final StorageReference storageReferenceImage = mStorageReferenceImages.child(uri.getLastPathSegment());
        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "Firebase Storage");
        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                Log.d("MainActivity", "failed to create Firebase Storage directory");
            }
        }

        final File localFile = new File(mediaStorageDir, uri.getLastPathSegment());
        try {
            localFile.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }

        showHorizontalProgressDialog("Downloading", "Please wait...");
        storageReferenceImage.getFile(localFile).addOnSuccessListener(new OnSuccessListener<FileDownloadTask.TaskSnapshot>() {
            @Override
            public void onSuccess(FileDownloadTask.TaskSnapshot taskSnapshot) {
                hideProgressDialog();
                showAlertDialog(MainActivity.this, "Download Complete", localFile.getAbsolutePath(), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        findViewById(R.id.button_step_4).setEnabled(false);
                        findViewById(R.id.button_step_5).setEnabled(true);
                    }
                });

                Glide.with(MainActivity.this)
                        .load(localFile)
                        .into(mImageView);
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception exception) {
                // Handle any errors
                hideProgressDialog();
                exception.printStackTrace();
            }
        }).addOnProgressListener(new OnProgressListener<FileDownloadTask.TaskSnapshot>() {
            @Override
            public void onProgress(FileDownloadTask.TaskSnapshot taskSnapshot) {
                int progress = (int) (100 * (float) taskSnapshot.getBytesTransferred() / taskSnapshot.getTotalByteCount());
                Log.i("Progress", progress + "");
                updateProgress(progress);
            }
        });
    }

    private void deleteFile(Uri uri) {
        showProgressDialog("Deleting", "Please wait...");
        StorageReference storageReferenceImage = mStorageReferenceImages.child(uri.getLastPathSegment());
        storageReferenceImage.delete().addOnSuccessListener(new OnSuccessListener<Void>() {
            @Override
            public void onSuccess(Void aVoid) {
                hideProgressDialog();
                showAlertDialog(MainActivity.this, "Success", "File deleted successfully.", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        mImageView.setImageResource(R.drawable.placeholder_image);
                        findViewById(R.id.button_step_3).setEnabled(true);
                        findViewById(R.id.button_step_4).setEnabled(false);
                        findViewById(R.id.button_step_5).setEnabled(false);
                    }
                });
                File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                        Environment.DIRECTORY_PICTURES), "Firebase Storage");
                if (!mediaStorageDir.exists()) {
                    if (!mediaStorageDir.mkdirs()) {
                        Log.d("MainActivity", "failed to create Firebase Storage directory");
                    }
                }
                deleteFiles(mediaStorageDir);
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception exception) {
                hideProgressDialog();
                exception.printStackTrace();
            }
        });
    }

    private void deleteFiles(File directory) {
        if (directory.isDirectory())
            for (File child : directory.listFiles())
                child.delete();
    }
}

service firebase.storage {
   match /b/**something**.appspot.com/o {
     match /{allPaths=**} {
       allow read, write: if request.auth != null;
     }
   }
 }

service firebase.storage {
  match /b/**something**.appspot.com/o {
    match /{allPaths=**} {
      allow read, write;
    }
  }
}