title: Download image from firebase to external sd Card using url
body: <p>i have uploaded image file in my firebase. I have stored url to firebase-database. During storing process,To get url i used <code>Uri downloadUri = taskSnapshot.getDownloadUrl();</code> 
  Now i want to download that image file from that url when button is clicked and want to store that image file into specific folder of sd card let say "New Folder"
  help me with following code....</p>
  
  <pre><code>FirebaseStorage mFirebaseStorage;
  StorageReference httpsReference;
  
  mFirebaseStorage = FirebaseStorage.getInstance();
  httpsReference = mFirebaseStorage.getReferenceFromUrl(downloadUri);
  
  Button b = findViewById(R.id.button);
  b.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
          //what??
      }
  });
  </code></pre>