Cacher is the code snippet organizer for pro developers

//    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>

public class TestActivity extends AppCompatActivity {

    private DatabaseReference _mDatabase;
    private Button _selectImage;
    private FirebaseStorage _mFireStorage;
    private static final int GALLERY_INTENT = 1;

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

        _mFireStorage = FirebaseStorage.getInstance();
        _selectImage = findViewById(R.id.button);

        //click upload button
        _selectImage.setOnClickListener(new View.OnClickListener() {
            @RequiresApi(api = Build.VERSION_CODES.M)
            @Override
            public void onClick(View v) {
                if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
                } else {
                    getPhoto();
                }
            }
        });
    }

    private void getPhoto() {
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType("image/*");
        startActivityForResult(intent, GALLERY_INTENT);
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == GALLERY_INTENT && resultCode == RESULT_OK) {
            Uri uri = data.getData();
            StorageReference filePath = _mFireStorage.getReference().child("photos").child(uri.getLastPathSegment());

            filePath.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                @Override
                public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                    Toast.makeText(TestActivity.this, "Uploaded", Toast.LENGTH_SHORT).show();
                }
            }).addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    //deal with failure
                }
            });
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == GALLERY_INTENT) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                getPhoto();
            }
        }
    }
}