为什么我的代码从 Firebase 提取数据两次?安卓工作室

Question

我不记得我做错了什么，因为我之前已经修复过这个问题。 我正在尝试做的是从Firebase检索职位发布数据并将其放在我的列表视图中，但是当我这样做时，职位发布有重复项。关于如何解决这个问题的任何想法？

我将在下面添加日志和代码。

这是日志，我使用脚本"获取作业计数第一计数"中的日志来记录日志计数

05-28 20:24:06.391 17592-17592/test.com.jobTestApp D/FindWorkFragment: getPhotos: getting photos
getPhotos: getting jobs count first count = 0
05-28 20:24:06.772 17592-17592/test.com.jobTestApp D/FindWorkFragment: onDataChange: getJOBS  {job_headline=Website, date_posted=yesterday, user_country=United States, time_frame= 7 days, job_desc=Hello, fullname=Tom, category=Web Development, budget=30}
onDataChange: jobs count = 1
onDataChange: getJOBS  {job_headline=Website, date_posted=today, user_country=United States, user_id=QkGIMPFXDoPfpnwnPileLRtyR243, time_frame=6 days, job_desc=stuff, fullname=Odi Ohn, category=Web Development, budget=24}
onDataChange: jobs count = 2
05-28 20:24:06.773 17592-17592/test.com.jobTestApp D/FindWorkFragment: onDataChange: getJOBS  {job_headline=Website, date_posted=yesterday, user_country=United States, time_frame= 7 days, job_desc=Hello, fullname=Tom, category=Web Development, budget=30}
onDataChange: jobs count = 3
onDataChange: getJOBS  {job_headline=Website, date_posted=today, user_country=United States, user_id=QkGIMPFXDoPfpnwnPileLRtyR243, time_frame=6 days, job_desc=stuff, fullname=Odi Ohn, category=Web Development, budget=24}
onDataChange: jobs count = 4
05-28 20:24:06.776 17592-17592/test.com.jobTestApp D/FindWorkFragment: onDataChange: jobs count = 4

这是代码：

public class FindWorkFragment extends Fragment implements AdapterView.OnItemSelectedListener{
private static final String TAG = "FindWorkFragment";
private ImageView btnBack;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference myRef;
private ArrayList<PostJob> mJobs;
private ArrayList<PostJob> mPaginatedPhotos;
private ArrayList<String> mJobsinCat;
private ListView mListView;
private JobFeedListAdapter mAdapter;
private int mResults;
private Spinner mSearchCat;
private String searchCat;
private ArrayAdapter<CharSequence> mSearchCategoryAdapter;
public static FindWorkFragment newInstance(int instance) {
Bundle args = new Bundle();
args.putInt("argsInstance", instance);
FindWorkFragment thirdFragment = new FindWorkFragment();
thirdFragment.setArguments(args);
return thirdFragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_findwork, container, false);
final Fragment fragment = new FindWorkFragment();
mFirebaseDatabase = FirebaseDatabase.getInstance();
myRef = mFirebaseDatabase.getReference();
btnBack = (ImageView) view.findViewById(R.id.iv_back);
mSearchCat = (Spinner) view.findViewById(R.id.spSearchCat);
mSearchCategoryAdapter = ArrayAdapter.createFromResource(getActivity(), R.array.job_categories, android.R.layout.simple_spinner_item);
mSearchCategoryAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSearchCat.setAdapter(mSearchCategoryAdapter);
mSearchCat.setOnItemSelectedListener(this);
mListView = (ListView) view.findViewById(R.id.joblistview);
mJobsinCat = new ArrayList<>();
mJobs = new ArrayList<>();
getJobsinCat();
btnBack.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
ft.replace(R.id.main_frag_container, new HomeDashboardFragment());
ft.commit();
}
});
return view;
}
private void getJobsinCat(){
Log.d(TAG, "getFollowing: searching for following");
String key = myRef.child("Web Development").push().getKey();
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(getString(R.string.dbname_jobs))
.child("United States")
.child("Web Development");
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.d(TAG, "onDataChange: found user: " +
singleSnapshot.getKey());
mJobsinCat.add(singleSnapshot.getKey().toString());
}
//mJobsinCat.add(FirebaseAuth.getInstance().getCurrentUser().getUid());
//get the photos
getPhotos();
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getPhotos(){
Log.d(TAG, "getPhotos: getting photos");
Log.d(TAG, "getPhotos: getting jobs count first count = " + mJobs.size() );
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
for(int i = 0; i < mJobsinCat.size(); i++){
final int count = i;
Query query = reference
.child(getString(R.string.dbname_jobs))
.child("United States")
.child("Web Development")
.orderByKey();
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
PostJob job = new PostJob();
Log.d(TAG, "onDataChange: getJOBS  " + singleSnapshot.getValue());
Map<String, Object> objectMap = (HashMap<String, Object>) singleSnapshot.getValue();
//job.setUser_country(objectMap.get("user_country").toString());
job.setJob_headline(objectMap.get("job_headline").toString());
job.setJob_desc(objectMap.get("job_desc").toString());
job.setBudget(objectMap.get("budget").toString());
job.setTime_frame(objectMap.get("time_frame").toString());
//job.setTags(objectMap.get(getString(R.string.field_tags)).toString());
//job.setPhoto_id(objectMap.get(getString(R.string.field_photo_id)).toString());
//job.setUser_id(objectMap.get(getString(R.string.field_user_id)).toString());
//job.setDate_posted(objectMap.get("date_posted").toString());
//job.setImage_path(objectMap.get(getString(R.string.field_image_path)).toString());
/*
// soon going to be the proposals
ArrayList<Comment> comments = new ArrayList<Comment>();
for (DataSnapshot dSnapshot : singleSnapshot
.child(getString(R.string.field_comments)).getChildren()){
Comment comment = new Comment();
comment.setUser_id(dSnapshot.getValue(Comment.class).getUser_id());
comment.setComment(dSnapshot.getValue(Comment.class).getComment());
comment.setDate_created(dSnapshot.getValue(Comment.class).getDate_created());
comments.add(comment);
}
photo.setComments(comments);*/
mJobs.add(job);
}
if(count >= mJobsinCat.size() -1){
//display our photos
displayPhotos();
Log.d(TAG, "onDataChange: jobs count = " + mJobs.size());
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
private void displayPhotos(){
mPaginatedPhotos = new ArrayList<>();
if(mJobs != null){
try{
/*
Collections.sort(mJobs, new Comparator<PostJob>() {
@Override
public int compare(PostJob o1, PostJob o2) {
return o2.getDate_posted().compareTo(o1.getDate_posted());
}
});*/
int iterations = mJobs.size();
if(iterations > 10){
iterations = 10;
}
mResults = 10;
for(int i = 0; i < iterations; i++){
mPaginatedPhotos.add(mJobs.get(i));
}
mAdapter = new JobFeedListAdapter(getActivity(), R.layout.layout_jobfeed_listitem, mPaginatedPhotos);
mListView.setAdapter(mAdapter);
}catch (NullPointerException e){
Log.e(TAG, "displayPhotos: NullPointerException: " + e.getMessage() );
}catch (IndexOutOfBoundsException e){
Log.e(TAG, "displayPhotos: IndexOutOfBoundsException: " + e.getMessage() );
}
}
}
public void displayMorePhotos(){
Log.d(TAG, "displayMorePhotos: displaying more photos");
try{
if(mJobs.size() > mResults && mJobs.size() > 0){
int iterations;
if(mJobs.size() > (mResults + 10)){
Log.d(TAG, "displayMorePhotos: there are greater than 10 more photos");
iterations = 10;
}else{
Log.d(TAG, "displayMorePhotos: there is less than 10 more photos");
iterations = mJobs.size() - mResults;
}
//add the new photos to the paginated results
for(int i = mResults; i < mResults + iterations; i++){
mPaginatedPhotos.add(mJobs.get(i));
}
mResults = mResults + iterations;
mAdapter.notifyDataSetChanged();
}
}catch (NullPointerException e){
Log.e(TAG, "displayPhotos: NullPointerException: " + e.getMessage() );
}catch (IndexOutOfBoundsException e){
Log.e(TAG, "displayPhotos: IndexOutOfBoundsException: " + e.getMessage() );
}
}
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
searchCat = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}

}

Answer 1

查看您在循环中添加query.addListenerForSingleValueEventforgetPhotos()，以便它根据mJobsinCat.size()多次执行，将其从循环中拉出以进行一次调用

private void getPhotos(){
Log.d(TAG, "getPhotos: getting photos");
Log.d(TAG, "getPhotos: getting jobs count first count = " + mJobs.size() );
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();

Query query = reference
.child(getString(R.string.dbname_jobs))
.child("United States")
.child("Web Development")
.orderByKey();
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
PostJob job = new PostJob();
Log.d(TAG, "onDataChange: getJOBS  " + singleSnapshot.getValue());
Map<String, Object> objectMap = (HashMap<String, Object>) singleSnapshot.getValue();
//job.setUser_country(objectMap.get("user_country").toString());
job.setJob_headline(objectMap.get("job_headline").toString());
job.setJob_desc(objectMap.get("job_desc").toString());
job.setBudget(objectMap.get("budget").toString());
job.setTime_frame(objectMap.get("time_frame").toString());
//job.setTags(objectMap.get(getString(R.string.field_tags)).toString());
//job.setPhoto_id(objectMap.get(getString(R.string.field_photo_id)).toString());
//job.setUser_id(objectMap.get(getString(R.string.field_user_id)).toString());
//job.setDate_posted(objectMap.get("date_posted").toString());
//job.setImage_path(objectMap.get(getString(R.string.field_image_path)).toString());
/*
// soon going to be the proposals
ArrayList<Comment> comments = new ArrayList<Comment>();
for (DataSnapshot dSnapshot : singleSnapshot
.child(getString(R.string.field_comments)).getChildren()){
Comment comment = new Comment();
comment.setUser_id(dSnapshot.getValue(Comment.class).getUser_id());
comment.setComment(dSnapshot.getValue(Comment.class).getComment());
comment.setDate_created(dSnapshot.getValue(Comment.class).getDate_created());
comments.add(comment);
}
photo.setComments(comments);*/
mJobs.add(job);
}
Log.d(TAG, "onDataChange: jobs count = " + mJobs.size());
if( mJobs.size()>0){
//display our photos
displayPhotos();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}