我正在尝试从Firestore提取问题的详细信息。必须从
different collections获取数据。我有
questionCollection -（questionID，titleOfQuestion，用户ID等）；
评论集合-（评论ID，问题ID，用户ID）；
questionLikeCollection -（（questionID，userID）
QuestionDetailActivity.class
public class QuestionDetailActivity extends AppCompatActivity {
private static final String TAG = "QuestionDetailActivity";
private Context mContext;
private TextView questionTitleTv;
private RadioGroup radioLL;
private EditText answerEt;
private LinearLayout checkboxLL;
private LinearLayout commentLL;
private FirebaseFirestore db = null;
private String questionID;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_question_detail);
mContext = QuestionDetailActivity.this;
db = FirebaseFirestore.getInstance();
questionTitleTv = findViewById(R.id.tv_question_title);
radioLL = findViewById(R.id.ll_radio);
answerEt = findViewById(R.id.et_answer);
checkboxLL = findViewById(R.id.ll_checkbox);
commentLL = findViewById(R.id.ll_comments);
if (getIntent() != null) {
questionID = getIntent().getExtras().getString("keyQuestionID", "");
}
if (!questionID.isEmpty()) {
getQuestionDetail(questionID);
showComments(questionID);
showLike(questionID);
}
}
private void showLike(String questionID) {
DocumentReference docRef = db.collection("questionLikeCollection").document(questionID);
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
// highlight like button...
} else {
Log.d(TAG, "No such document");
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});
}
private void showComments(String questionID) {
db.collection("commentCollection").whereEqualTo("questionID", questionID)
.get()
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
@Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
if (queryDocumentSnapshots.isEmpty()) {
Log.d(TAG, "onSuccess: LIST EMPTY");
return;
} else {
// Convert the whole Query Snapshot to a list
// of objects directly! No need to fetch each
// document.
List<CommentBO> commentList = queryDocumentSnapshots.toObjects(CommentBO.class);
if (commentList != null && commentList.size() > 0) {
for (int x = 0; x < commentList.size(); x++) {
try {
LinearLayout.LayoutParams childParam = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
childParam.setMargins(20, 10, 0, 0);
View commentByView = LayoutInflater.from(mContext).inflate(R.layout.item_comment, null);
TextView tvCommenter = (TextView) commentByView.findViewById(R.id.item_tv_commenter_name);
TextView tvCommenterComment = (TextView) commentByView.findViewById(R.id.item_tv_commenter_comment);
TextView tvCommentDate = (TextView) commentByView.findViewById(R.id.item_tv_comment_date);
tvCommenter.setText(commentList.get(x).getCommentedBy());
tvCommenterComment.setText(commentList.get(x).getComment());
///tvCommentDate.setText();
commentLL.addView(commentByView, childParam);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
});
}
private void getQuestionDetail(String questionID) {
DocumentReference docRef = db.collection("questionCollection").document(questionID);
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
Log.d(TAG, "DocumentSnapshot data: " + document.getData());
QuestionBO questionBO = document.toObject(QuestionBO.class);
updateView(questionBO);
} else {
Log.d(TAG, "No such document");
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});
}
private void updateView(QuestionBO mQuestionBO) {
if (mQuestionBO != null) {
questionTitleTv.setText(mQuestionBO.getTitle());
switch (mQuestionBO.getQuestionType()) {
case CHECKBOX:
checkboxLL.setVisibility(View.VISIBLE);
if (mQuestionBO.getOptions() != null && mQuestionBO.getOptions().size() > 0) {
checkboxLL.removeAllViews();
for (int x = 0; x < mQuestionBO.getOptions().size(); x++) {
final CheckBox subCheckbox = new CheckBox(mContext);
subCheckbox.setText(mQuestionBO.getOptions().get(x));
subCheckbox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
}
});
checkboxLL.addView(subCheckbox, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
}
}
break;
case RADIO:
radioLL.setVisibility(View.VISIBLE);
if (mQuestionBO.getOptions() != null && mQuestionBO.getOptions().size() > 0) {
radioLL.removeAllViews();
for (int x = 0; x < mQuestionBO.getOptions().size(); x++) {
final RadioButton subRadio = new RadioButton(mContext);
subRadio.setText(mQuestionBO.getOptions().get(x));
radioLL.addView(subRadio, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
}
}
break;
case DESCRIPTIVE:
answerEt.setVisibility(View.VISIBLE);
break;
}
}
}
}
activity_question_detail.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp"
tools:context=".QuestionDetailActivity">
<TextView
android:id="@+id/tv_question_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Hello I am a question"
android:textColor="@android:color/black"
android:textSize="20sp" />
<LinearLayout
android:id="@+id/ll_checkbox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:visibility="gone" />
<RadioGroup
android:id="@+id/ll_radio"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:visibility="gone" />
<EditText
android:id="@+id/et_answer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:drawableLeft="@drawable/like_it"
android:drawablePadding="8dp"
android:gravity="center"
android:src="@drawable/like_it"
android:text="33"
android:textSize="18sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:drawableLeft="@drawable/like_it"
android:drawablePadding="8dp"
android:gravity="center"
android:src="@drawable/like_it"
android:text="33"
android:textSize="18sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:drawableLeft="@drawable/like_it"
android:drawablePadding="8dp"
android:gravity="center"
android:src="@drawable/like_it"
android:text="33"
android:textSize="18sp" />
</RelativeLayout>
<LinearLayout
android:id="@+id/ll_comments"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"></LinearLayout>
</LinearLayout>
我想显示问题的详细信息，就像stackoverflow 一样。如问题标题，喜欢，收藏，评论，用户名。每个数据都在单独的集合中。我如何在一次交易中称呼它。以及如何减少来自Firestore的读取次数。