从帖子中获取价值

Question

我将如何循环，并从帖子节点获取这些值？我还是Firebase的新手......还使用了Java。

我的目标是特定的用户密钥：

mPostsRef.child(userKey)

谢谢！

Answer 1

要获取正文和标题，请尝试以下操作：

def createTree(dataSet,labels,data_full,labels_full):
    classList=[example[-1] for example in dataSet]
    if classList.count(classList[0])==len(classList):
        return classList[0]
    if len(dataSet[0])==1:
        return majorityCnt(classList)
    bestFeat=chooseBestFeatureToSplit(dataSet,labels)
    bestFeatLabel=labels[bestFeat]
    myTree={bestFeatLabel:{}}
    featValues=[example[bestFeat] for example in dataSet]
    uniqueVals=set(featValues)
    if type(dataSet[0][bestFeat]).__name__=='str':
        currentlabel=labels_full.index(labels[bestFeat])
        featValuesFull=[example[currentlabel] for example in data_full]
        uniqueValsFull=set(featValuesFull)
    del(labels[bestFeat])
    #针对bestFeat的每个取值，划分出一个子树。
    for value in uniqueVals:
        subLabels=labels[:]
        if type(dataSet[0][bestFeat]).__name__=='str':
            uniqueValsFull.remove(value)
        myTree[bestFeatLabel][value]=createTree(splitDataSet\
         (dataSet,bestFeat,value),subLabels,data_full,labels_full)
    if type(dataSet[0][bestFeat]).__name__=='str':
        for value in uniqueValsFull:
            myTree[bestFeatLabel][value]=majorityCnt(classList)
    return myTree

快照将位于节点DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Posts").child(userKey); ref.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for(DataSnapshot datas: dataSnapshot.getChildren()){ String body=datas.child("body").getValue().toString(); String title=datas.child("title").getValue().toString(); } } @Override public void onCancelled(DatabaseError error) { } }); 下的直接键处，然后您可以在随机键内循环并获取正文和标题的值。