无法使用Query过滤Firebase数据库中的值

Question

我有一个聊天应用，当用户点击其他用户的个人资料时，我会使用以下代码检查此用户是否已经存在聊天：

<script> Sfdump = window.Sfdump || (function (doc) { var refStyle = doc.createElement('style'), rxEsc = /([.*+?^${}()|\[\]\/\\])/g, idRx = /\bsf-dump-\d+-ref[012]\w+\b/, keyHint = 0 <= navigator.platform.toUpperCase().indexOf('MAC') ? 'Cmd' : 'Ctrl', addEventListener = function (e, n, cb) { e.addEventListener(n, cb, false); }; (doc.documentElement.firstElementChild || doc.documentElement.children[0]).appendChild(refStyle); if (!doc.addEventListener) { addEventListener = function (element, eventName, callback) { element.attachEvent('on' + eventName, function (e) { e.preventDefault = function () {e.returnValue = false;}; e.target = e.srcElement; callback(e); }); }; } function toggle(a, recursive) { var s = a.nextSibling || {}, oldClass = s.className, arrow, newClass; if ('sf-dump-compact' == oldClass) { arrow = '&#9660;'; newClass = 'sf-dump-expanded'; } else if ('sf-dump-expanded' == oldClass) { arrow = '&#9654;'; newClass = 'sf-dump-compact'; } else { return false; } a.lastChild.innerHTML = arrow; s.className = newClass; if (recursive) { try { a = s.querySelectorAll('.'+oldClass); for (s = 0; s < a.length; ++s) { if (a[s].className !== newClass) { a[s].className = newClass; a[s].previousSibling.lastChild.innerHTML = arrow; } } } catch (e) { } } return true; }; return function (root) { root = doc.getElementById(root); function a(e, f) { addEventListener(root, e, function (e) { if ('A' == e.target.tagName) { f(e.target, e); } else if ('A' == e.target.parentNode.tagName) { f(e.target.parentNode, e); } }); }; function isCtrlKey(e) { return e.ctrlKey || e.metaKey; } addEventListener(root, 'mouseover', function (e) { if ('' != refStyle.innerHTML) { refStyle.innerHTML = ''; } }); a('mouseover', function (a) { if (a = idRx.exec(a.className)) { try { refStyle.innerHTML = 'pre.sf-dump .'+a[0]+'{background-color: #B729D9; color: #FFF !important; border-radius: 2px}'; } catch (e) { } } }); a('click', function (a, e) { if (/\bsf-dump-toggle\b/.test(a.className)) { e.preventDefault(); if (!toggle(a, isCtrlKey(e))) { var r = doc.getElementById(a.getAttribute('href').substr(1)), s = r.previousSibling, f = r.parentNode, t = a.parentNode; t.replaceChild(r, a); f.replaceChild(a, s); t.insertBefore(s, r); f = f.firstChild.nodeValue.match(indentRx); t = t.firstChild.nodeValue.match(indentRx); if (f && t && f[0] !== t[0]) { r.innerHTML = r.innerHTML.replace(new RegExp('^'+f[0].replace(rxEsc, '\\$1'), 'mg'), t[0]); } if ('sf-dump-compact' == r.className) { toggle(s, isCtrlKey(e)); } } if (doc.getSelection) { try { doc.getSelection().removeAllRanges(); } catch (e) { doc.getSelection().empty(); } } else { doc.selection.empty(); } } }); var indentRx = new RegExp('^('+(root.getAttribute('data-indent-pad') || ' ').replace(rxEsc, '\\$1')+')+', 'm'), elt = root.getElementsByTagName('A'), len = elt.length, i = 0, t = []; while (i < len) t.push(elt[i++]); elt = root.getElementsByTagName('SAMP'); len = elt.length; i = 0; while (i < len) t.push(elt[i++]); root = t; len = t.length; i = t = 0; while (i < len) { elt = root[i]; if ("SAMP" == elt.tagName) { elt.className = "sf-dump-expanded"; a = elt.previousSibling || {}; if ('A' != a.tagName) { a = doc.createElement('A'); a.className = 'sf-dump-ref'; elt.parentNode.insertBefore(a, elt); } else { a.innerHTML += ' '; } a.title = (a.title ? a.title+'\n[' : '[')+keyHint+'+click] Expand all children'; a.innerHTML += '<span>&#9660;</span>'; a.className += ' sf-dump-toggle'; if ('sf-dump' != elt.parentNode.className) { toggle(a); } } else if ("sf-dump-ref" == elt.className && (a = elt.getAttribute('href'))) { a = a.substr(1); elt.className += ' '+a; if (/[\[{]$/.test(elt.previousSibling.nodeValue)) { a = a != elt.nextSibling.id && doc.getElementById(a); try { t = a.nextSibling; elt.appendChild(a); t.parentNode.insertBefore(a, t); if (/^[@#]/.test(elt.innerHTML)) { elt.innerHTML += ' <span>&#9654;</span>'; } else { elt.innerHTML = '<span>&#9654;</span>'; elt.className = 'sf-dump-ref'; } elt.className += ' sf-dump-toggle'; } catch (e) { if ('&' == elt.innerHTML.charAt(0)) { elt.innerHTML = '&#8230;'; elt.className = 'sf-dump-ref'; } } } } ++i; } }; })(document); </script><style> pre.sf-dump { display: block; white-space: pre; padding: 5px; } pre.sf-dump span { display: inline; } pre.sf-dump .sf-dump-compact { display: none; } pre.sf-dump abbr { text-decoration: none; border: none; cursor: help; } pre.sf-dump a { text-decoration: none; cursor: pointer; border: 0; outline: none; }pre.sf-dump{background-color:#fff; color:#222; line-height:1.2em; font-weight:normal; font:12px Monaco, Consolas, monospace; word-wrap: break-word; white-space: pre-wrap; position:relative; z-index:100000}pre.sf-dump .sf-dump-num{color:#a71d5d}pre.sf-dump .sf-dump-const{color:#795da3}pre.sf-dump .sf-dump-str{color:#df5000}pre.sf-dump .sf-dump-cchr{color:#222}pre.sf-dump .sf-dump-note{color:#a71d5d}pre.sf-dump .sf-dump-ref{color:#a0a0a0}pre.sf-dump .sf-dump-public{color:#795da3}pre.sf-dump .sf-dump-protected{color:#795da3}pre.sf-dump .sf-dump-private{color:#795da3}pre.sf-dump .sf-dump-meta{color:#b729d9}pre.sf-dump .sf-dump-key{color:#df5000}pre.sf-dump .sf-dump-index{color:#a71d5d}</style><pre class=sf-dump id=sf-dump-1820305802 data-indent-pad="  "><span class=sf-dump-note>array:7</span> [<samp>
  "<span class=sf-dump-key>abcd</span>" => "<span class=sf-dump-str title="4 characters">efgh</span>"
  "<span class=sf-dump-key>wddf</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
  "<span class=sf-dump-key>asfdf</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
  "<span class=sf-dump-key>asedf</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
  "<span class=sf-dump-key>asdif</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
  "<span class=sf-dump-key>asodf</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
  "<span class=sf-dump-key>aspdf</span>" => "<span class=sf-dump-str title="8 characters">asdfsadf</span>"
</samp>]
</pre><script>Sfdump("sf-dump-1820305802")</script>

这是我的数据库快照：

由于有一个名为“Tim Cook”的值，我点击了Tim Cook的个人资料，它应该打开现有的聊天活动，但每次打开新的聊天活动并且我的查询无法正常工作。我想知道我在做什么错误，这也是很好的技巧，还是我应该以另一种方式处理它？ 提前谢谢。

Answer 1

因为你想念孩子而无法工作。正如我在屏幕截图中看到的那样，chatId丢失了。要解决此问题，请更改以下代码行：

FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
String uid = firebaseUser.getUid();

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference userIdRef = rootRef.child("chats").child(uid);
Query query = userIdRef.orderByChild("otherUsersName").equalTo("Tim Cook");
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            if (ds.exists()) {
                Log.d("TAG", ds.child("otherUsersName").getValue(String.class));
                //open the exsiting chat
            } else {
                //start a new chat
            }
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
query.addListenerForSingleValueEvent(eventListener);