title: Android Firebase delete crash application on remove value
body: <p>I want to delete data from list view also from firebase.</p>
  
  <pre><code> lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
          @Override
          public boolean onItemLongClick(AdapterView&lt;?&gt; parent, final View view, final int position, long id) {
              mDatabaseRef.addValueEventListener(new ValueEventListener() {
                  @Override
                  public void onDataChange(DataSnapshot dataSnapshot) {
                      for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                         DatabaseReference s =snapshot.getRef();
                          mDatabaseRef.child(String.valueOf(s)).removeValue();
                      }
                  }
  </code></pre>
  
  <p>Application crashes on this line: <code>mDatabaseRef.child(String.valueOf(s)).removeValue();</code> 
  I also use <code>setValue(null);</code></p>
  
  <p><a href="https://i.stack.imgur.com/1qsZj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1qsZj.png" alt="delete only this value"></a></p>