android - Android Studio 使用 Firebase 数据库的应用中未显示已发布的图片

Question

地狱。我是一名 cs 学生，正在为我的项目开发一个应用程序，在这个项目中，用户必须能够发布图像，并且它必须在发布后处于主要活动中，我编写了代码并且没有错误，数据存储在firebase存储和实时数据库中，但唯一的问题是当我运行应用程序时，帖子可见但图像不存在..它显示空白而不是图片，帖子也不在他们应该是正确的顺序。如果我注销并再次登录并添加新帖子，它会低于旧帖子。

这是我的帖子活动：

public class PostActivity extends AppCompatActivity
{
    private Toolbar mToolbar;
    private ProgressDialog loadingBar;

    private ImageButton SelectPostImage;
    private Button UpdatePostButton;
    private EditText PostDescription;

    private static final int Gallery_Pick = 1;
    private Uri ImageUri;
    private String Description;

    private StorageReference PostsImagesRefrence;
    private DatabaseReference UsersRef, PostsRef;
    private FirebaseAuth mAuth;

    private String saveCurrentDate, saveCurrentTime, postRandomName, downloadUrl, current_user_id;
    private long countPosts = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_post);


        mAuth = FirebaseAuth.getInstance();
        current_user_id = mAuth.getCurrentUser().getUid();

        PostsImagesRefrence = FirebaseStorage.getInstance().getReference();
        UsersRef = FirebaseDatabase.getInstance().getReference().child("Users");
        PostsRef = FirebaseDatabase.getInstance().getReference().child("Posts");


        SelectPostImage = (ImageButton) findViewById(R.id.select_post_image);
        UpdatePostButton = (Button) findViewById(R.id.new_post_button);
        PostDescription =(EditText) findViewById(R.id.post_caption);
        loadingBar = new ProgressDialog(this);


        mToolbar = (Toolbar) findViewById(R.id.update_post_page_toolbar);
        setSupportActionBar(mToolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setTitle("Update Post");


        SelectPostImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                OpenGallery();
            }
        });


        UpdatePostButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                ValidatePostInfo();
            }
        });
    }



    private void ValidatePostInfo()
    {
        Description = PostDescription.getText().toString();

        if(ImageUri == null)
        {
            Toast.makeText(this, "Please select post image...", Toast.LENGTH_SHORT).show();
        }
        else if(TextUtils.isEmpty(Description))
        {
            Toast.makeText(this, "Please say something about your image...", Toast.LENGTH_SHORT).show();
        }
        else
        {
            loadingBar.setTitle("Adding New Post");
            loadingBar.setMessage("Please wait for a while...");
            loadingBar.show();
            loadingBar.setCanceledOnTouchOutside(true);

            StoringImageToFirebaseStorage();
        }
    }



    private void StoringImageToFirebaseStorage()
    {
        Calendar calFordDate = Calendar.getInstance();
        SimpleDateFormat currentDate = new SimpleDateFormat("dd-MMMM-yyyy");
        saveCurrentDate = currentDate.format(calFordDate.getTime());

        //Calendar calFordTime = Calendar.getInstance();
        //SimpleDateFormat currentTime = new SimpleDateFormat("HH:mm");
        //saveCurrentTime = currentTime.format(calFordDate.getTime());

        Calendar calForTime=Calendar.getInstance();
        @SuppressLint("SimpleDateFormat") SimpleDateFormat currentTime =new SimpleDateFormat("HH:mm:ss");
        saveCurrentTime=currentTime.format(calForTime.getTime());

        postRandomName = saveCurrentDate + saveCurrentTime;


        StorageReference filePath = PostsImagesRefrence.child("Post Images").child(ImageUri.getLastPathSegment() + postRandomName + ".jpg");

        filePath.putFile(ImageUri).addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task)
            {
                if(task.isSuccessful())
                {
                    //downloadUrl = task.getResult().getMetadata().getReference().getDownloadUrl().toString();
                    downloadUrl = task.getResult().getStorage().getDownloadUrl().toString();

                    //Toast.makeText(PostActivity.this, "image uploaded successfully to Storage...", Toast.LENGTH_SHORT).show();

                    SavingPostInformationToDatabase();

                }
                else
                {
                    String message = task.getException().getMessage();
                    Toast.makeText(PostActivity.this, "Error occured: " + message, Toast.LENGTH_SHORT).show();
                }
            }
        });
    }




    private void SavingPostInformationToDatabase()
    {
        PostsRef.addValueEventListener(new ValueEventListener()   //counting the number of posts
        {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot)
            {
                if(snapshot.exists())
                {
                    countPosts = snapshot.getChildrenCount();
                }
                else
                {
                    countPosts = 0;
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error)
            {

            }
        });

        UsersRef.child(current_user_id).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot)
            {
                if(dataSnapshot.exists())
                {
                    String userFullName = dataSnapshot.child("fullname").getValue().toString();
                    String userProfileImage = dataSnapshot.child("profileimage").getValue().toString();

                    HashMap postsMap = new HashMap();
                    postsMap.put("uid", current_user_id);
                    postsMap.put("date", saveCurrentDate);
                    postsMap.put("time", saveCurrentTime);
                    postsMap.put("description", Description);
                    postsMap.put("postimage", downloadUrl);
                    postsMap.put("profileimage", userProfileImage);
                    postsMap.put("fullname", userFullName);
                    postsMap.put("counter", countPosts);
                    PostsRef.child(current_user_id + postRandomName).updateChildren(postsMap)
                            .addOnCompleteListener(new OnCompleteListener() {
                                @Override
                                public void onComplete(@NonNull Task task)
                                {
                                    if(task.isSuccessful())
                                    {
                                        SendUserToMainActivity();
                                        Toast.makeText(PostActivity.this, "New Post is updated successfully.", Toast.LENGTH_SHORT).show();
                                        loadingBar.dismiss();
                                    }
                                    else
                                    {
                                        Toast.makeText(PostActivity.this, "Error Occured while updating your post.", Toast.LENGTH_SHORT).show();
                                        loadingBar.dismiss();
                                    }
                                }
                            });
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }



    private void OpenGallery()
    {
        Intent galleryIntent = new Intent();
        galleryIntent.setAction(Intent.ACTION_GET_CONTENT);
        galleryIntent.setType("image/*");
        startActivityForResult(galleryIntent, Gallery_Pick);
    }



    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode==Gallery_Pick && resultCode==RESULT_OK && data!=null)
        {
            ImageUri = data.getData();
            SelectPostImage.setImageURI(ImageUri);
        }
    }



    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        int id = item.getItemId();

        if(id == android.R.id.home)
        {
            SendUserToMainActivity();
        }

        return super.onOptionsItemSelected(item);
    }



    private void SendUserToMainActivity()
    {
        Intent mainIntent = new Intent(PostActivity.this, MainActivity.class);
        startActivity(mainIntent);
    }
}

这是我的主要活动：

{
    private NavigationView navigationView;
    private DrawerLayout drawerLayout;
    private ActionBarDrawerToggle actionBarDrawerToggle;
    private RecyclerView postList;
    private Toolbar mToolbar;

    private CircleImageView NavProfileImage;
    private TextView NavProfileUserName;
    private ImageButton AddNewPostButton;

    private FirebaseAuth mAuth;
    private DatabaseReference UsersRef, PostsRef, LikesRref;

    String currentUserID;
    Boolean LikeChecker = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mAuth = FirebaseAuth.getInstance();
        currentUserID = mAuth.getCurrentUser().getUid();
        UsersRef = FirebaseDatabase.getInstance().getReference().child("Users");
        PostsRef = FirebaseDatabase.getInstance().getReference().child("Posts");
        LikesRref = FirebaseDatabase.getInstance().getReference().child("Likes");

        mToolbar = (Toolbar) findViewById(R.id.main_page_toolbar);
        setSupportActionBar(mToolbar);
        getSupportActionBar().setTitle("Home");

        AddNewPostButton = (ImageButton) findViewById(R.id.add_new_post_button);

        drawerLayout = (DrawerLayout) findViewById(R.id.drawable_layout);
        actionBarDrawerToggle = new ActionBarDrawerToggle(MainActivity.this , drawerLayout, R.string.drawer_open , R.string.drawer_close);
        drawerLayout.addDrawerListener(actionBarDrawerToggle);
        actionBarDrawerToggle.syncState();
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        navigationView = (NavigationView) findViewById(R.id.navigation_view);

        postList = (RecyclerView) findViewById(R.id.all_users_post_list);
        postList.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        linearLayoutManager.setReverseLayout(true);
        linearLayoutManager.setStackFromEnd(true);
        postList.setLayoutManager(linearLayoutManager);


        View navView = navigationView.inflateHeaderView(R.layout.navigation_header);
        NavProfileImage = (CircleImageView) navView.findViewById(R.id.nav_profile_image);
        NavProfileUserName = (TextView) navView.findViewById(R.id.nav_profile_full_name);



        UsersRef.child(currentUserID).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot)
            {
                if(snapshot.exists())
                {
                    if (snapshot.hasChild("fullname"))
                    {
                        String fullname = snapshot.child("fullname").getValue().toString();
                        NavProfileUserName.setText(fullname);
                    }
                    if(snapshot.hasChild("profileimage"))
                    {
                        String image = snapshot.child("profileimage").getValue().toString();
                        Picasso.get().load(image).placeholder(R.drawable.profile).into(NavProfileImage);
                    }
                    else
                    {
                        //Toast.makeText(MainActivity.this,"Profile Name Do Not Exist!", Toast.LENGTH_SHORT).show();

                    }

                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });


        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item)
            {
                UserMenuSelector(item);
                return false;
            }
        });


        AddNewPostButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                SendUserToPostActivity();

            }
        });

        DisplayAllUsersPosts();

    }

    private void DisplayAllUsersPosts()
    {
        Query SortPosts = PostsRef.orderByChild("counter");

        FirebaseRecyclerOptions<Posts> options =
                new FirebaseRecyclerOptions.Builder<Posts>()
                .setQuery(PostsRef, Posts.class)
                .build();

        FirebaseRecyclerAdapter<Posts, PostsViewHolder> firebaseRecyclerAdapter =
                new FirebaseRecyclerAdapter<Posts, PostsViewHolder>(options) {
                    @Override
                    protected void onBindViewHolder(@NonNull PostsViewHolder holder, int position, @NonNull Posts model) {

                        final String PostKey = getRef(position).getKey();

                        holder.setFullname(model.getFullname());
                        holder.setTime(model.getTime());
                        holder.setDate(model.getDate());
                        holder.setDescription(model.getDescription());
                        holder.setProfileimage(getApplicationContext(), model.getProfileimage());
                        holder.setPostimage(getApplicationContext(), model.getPostimage());
                        //holder.setPostimage(getApplicationContext(), model.getPostimage());
                        //Picasso.

                        holder.setLikeButtonStatus(PostKey);

                        holder.mView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v)
                            {
                                Intent clickPostIntent = new Intent(MainActivity.this, ClickPostActivity.class);
                                clickPostIntent.putExtra("PostKey", PostKey);
                                startActivity(clickPostIntent);

                            }
                        });


                        holder.CommentPostButton.setOnClickListener(new View.OnClickListener()
                        {
                            @Override
                            public void onClick(View v)
                            {
                                Intent commentsIntent = new Intent(MainActivity.this, CommentsActivity.class);
                                commentsIntent.putExtra("PostKey", PostKey);
                                startActivity(commentsIntent);
                            }
                        });


                        holder.LikePostButton.setOnClickListener(new View.OnClickListener()
                        {
                            @Override
                            public void onClick(View v)
                            {
                                LikeChecker = true;

                                LikesRref.addValueEventListener(new ValueEventListener()
                                {
                                    @Override
                                    public void onDataChange(@NonNull DataSnapshot snapshot)
                                    {
                                        if(LikeChecker.equals(true))
                                        {
                                            if(snapshot.child(PostKey).hasChild(currentUserID)) //if like already exist
                                            {
                                                LikesRref.child(PostKey).child(currentUserID).removeValue();
                                                LikeChecker = false;
                                            }
                                            else
                                            {
                                                LikesRref.child(PostKey).child(currentUserID).setValue(true);
                                                LikeChecker = false;
                                            }
                                        }
                                    }

                                    @Override
                                    public void onCancelled(@NonNull DatabaseError error)
                                    {

                                    }
                                });
                            }
                        });
                    }

                    @NonNull
                    @Override
                    public PostsViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                       View view = LayoutInflater.from(parent.getContext())
                               .inflate(R.layout.all_post_layout,parent, false);

                       PostsViewHolder viewHolder = new PostsViewHolder(view);

                       return viewHolder;
                    }
                };


        firebaseRecyclerAdapter.startListening();
        postList.setAdapter(firebaseRecyclerAdapter);

        //postList.setAdapter(firebaseRecyclerAdapter);
    }

    public static class PostsViewHolder extends RecyclerView.ViewHolder
    {
        View mView;

        ImageButton LikePostButton, CommentPostButton;
        TextView DisplayNoOfLikes;
        int countLikes;
        String currentUserId;
        DatabaseReference LikesRef;

        public PostsViewHolder(@NonNull View itemView) {
            super(itemView);
            mView = itemView;

            LikePostButton = (ImageButton) mView.findViewById(R.id.like_button);
            CommentPostButton = (ImageButton) mView.findViewById(R.id.comment_button);
            DisplayNoOfLikes = (TextView) mView.findViewById(R.id.display_no_of_likes);

            LikesRef = FirebaseDatabase.getInstance().getReference().child("Likes");
            currentUserId = FirebaseAuth.getInstance().getCurrentUser().getUid();

        }

        public void setLikeButtonStatus(final String PostKey)
        {
            LikesRef.addValueEventListener(new ValueEventListener()
            {
                @Override
                public void onDataChange(@NonNull DataSnapshot snapshot)
                {
                    if(snapshot.child(PostKey).hasChild(currentUserId))
                    {
                        countLikes = (int) snapshot.child(PostKey).getChildrenCount(); //counting the number of likes
                        LikePostButton.setImageResource(R.drawable.like);
                        DisplayNoOfLikes.setText((Integer.toString(countLikes) + (" Like(s)")));
                    }
                    else
                    {
                        countLikes = (int) snapshot.child(PostKey).getChildrenCount(); //counting the number of likes
                        LikePostButton.setImageResource(R.drawable.dislike);
                        DisplayNoOfLikes.setText((Integer.toString(countLikes) + (" Like(s)")));
                    }
                }

                @Override
                public void onCancelled(@NonNull DatabaseError error)
                {

                }
            });
        }

        public void setFullname(String fullname)
        {
            TextView username = (TextView) mView.findViewById(R.id.post_user_name);
            username.setText(fullname);
        }

        public void setProfileimage(Context ctx, String profileimage)
        {
            CircleImageView image = (CircleImageView) mView.findViewById(R.id.post_profile_image);
            Picasso.get().load(profileimage).placeholder(R.drawable.profile).into(image);
        }

        public void setTime(String time)
        {
            TextView PostTime = (TextView) mView.findViewById(R.id.post_time);
            PostTime.setText("   " + time);
        }

        public void setDate(String date)
        {
            TextView PostDate = (TextView) mView.findViewById(R.id.post_date);
            PostDate.setText("   "+date);
        }

        public void setDescription(String description)
        {
            TextView PostDescription = (TextView) mView.findViewById(R.id.post_description);
            PostDescription.setText(description);
        }

        public void setPostimage(Context ctx, String postimage)
        {
            ImageView Postimage = (ImageView) mView.findViewById(R.id.post_image);
            Picasso.get().load(postimage).into(Postimage);
        }
    }



    private void SendUserToPostActivity()
    {
        Intent addNewPostIntent = new Intent(MainActivity.this, PostActivity.class);
        startActivity(addNewPostIntent);
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item)
    {
        if (actionBarDrawerToggle.onOptionsItemSelected(item))
        {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private void UserMenuSelector(MenuItem item)
    {
        switch (item.getItemId() )
        {
            case R.id.nav_post:
                SendUserToPostActivity();
                break;

        }
    }}

还有我的帖子类：

package com.example.pingoo;

public class Posts
{
    public String uid, time, date, postimage, description, profileimage,fullname;

    public Posts()
    {

    }


    public Posts(String uid, String time, String date, String postimage, String description, String profileimage, String fullname)
    {
        this.uid = uid;
        this.time = time;
        this.date = date;
        this.postimage = postimage;
        this.description = description;
        this.profileimage = profileimage;
        this.fullname = fullname;
    }

    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getPostimage() {
        return postimage;
    }

    public void setPostimage(String postimage) {
        this.postimage = postimage;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getProfileimage() {
        return profileimage;
    }

    public void setProfileimage(String profileimage) {
        this.profileimage = profileimage;
    }

    public String getFullname() {
        return fullname;
    }

    public void setFullname(String fullname) {
        this.fullname = fullname;
    }
}

我从主要活动中删除了一些不必要的部分，以使代码更短。

感谢您的帮助..提前谢谢您。

标签： androidfirebasefirebase-realtime-databasefile-upload