回收者视图未显示来自Firebase的图像，但正在显示文本

Question

我正在尝试使用Recycler View从Firebase提取并显示图像，但正在显示图像名称，但未显示图像。我已经检查了堆栈上几乎所有可用的东西，但是失败了，这就是为什么再次问这个类似的问题。

public class ImagesActivity extends AppCompatActivity{
    private RecyclerView mRecyclerView;
    private ImageAdapter mAdapter;
    private ProgressBar mProgressCircle;
    private DatabaseReference mDatabaseRef;
    private List<Upload> mUploads;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_images);
        //FirebaseAuth mAuth = FirebaseAuth.getInstance();
        mRecyclerView = findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        mRecyclerView.setAdapter(mAdapter);

        mProgressCircle = findViewById(R.id.progress_circle);
        mUploads = new ArrayList<>();
        mDatabaseRef = FirebaseDatabase.getInstance().getReference("uploads");
        mDatabaseRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                mUploads.clear();
                for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                    Upload upload = postSnapshot.getValue(Upload.class);
                    mUploads.add(upload);
                }
                mAdapter = new ImageAdapter(ImagesActivity.this, mUploads);
                mRecyclerView.setAdapter(mAdapter);
                mProgressCircle.setVisibility(View.INVISIBLE);
            }
            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(ImagesActivity.this, databaseError.getMessage(), Toast.LENGTH_SHORT).show();
                mProgressCircle.setVisibility(View.INVISIBLE);
            }
        });
    }
}

适配器类

  class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ViewHolder> {
    private List<Upload>list_data;
    private Context ct;

    public ImageAdapter(Context context, List<Upload> uploads) {
        this.list_data = uploads;
        this.ct = context;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.image_item,parent,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Upload ld=list_data.get(position);
        holder.tvname.setText(ld.getName());
        Picasso.with(ct).load(ld.getImageUrl()).into(holder.imageView);
    }

    @Override
    public int getItemCount() {
        return list_data.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        private ImageView imageView;
        private TextView tvname;
        public ViewHolder(View itemView) {
            super(itemView);
            imageView=(ImageView)itemView.findViewById(R.id.image_view_upload);
            tvname=(TextView)itemView.findViewById(R.id.text_view_name);
        }
    }
}

模型/ pojo类

public class Upload {
    private String name;
    private String imageUrl;
    public Upload() {
    }
    public Upload(String name, String imageUrl) {
        if (name.trim().equals("")) {
            name = "No Name";
        }
        this.name = name;
        this.imageUrl = imageUrl;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getImageUrl() {
        return imageUrl;
    }
    public void setImageUrl(String imageUrl) {
        this.imageUrl  = imageUrl;
    }
}

MainActivity

public class MainActivity extends AppCompatActivity {

    private static final int PICK_IMAGE_REQUEST = 1;

    private Button mButtonChooseImage;
    private Button mButtonUpload;
    private TextView mTextViewShowUploads;
    private EditText mEditTextFileName;
    private ImageView mImageView;
    private ProgressBar mProgressBar;
    private Uri mImageUri;
    private StorageReference mStorageRef;
    private DatabaseReference mDatabaseRef;
    private StorageTask mUploadTask;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FirebaseAuth mAuth = FirebaseAuth.getInstance();
        mButtonChooseImage = findViewById(R.id.button_choose_image);
        mButtonUpload = findViewById(R.id.button_upload);
        mTextViewShowUploads = findViewById(R.id.text_view_show_uploads);
        mEditTextFileName = findViewById(R.id.edit_text_file_name);
        mImageView = findViewById(R.id.image_view);
        mProgressBar = findViewById(R.id.progress_bar);
        mStorageRef = FirebaseStorage.getInstance().getReference("uploads");
        mDatabaseRef = FirebaseDatabase.getInstance().getReference("uploads");
        mButtonChooseImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openFileChooser();
            }
        });
        mButtonUpload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mUploadTask != null && mUploadTask.isInProgress()) {
                    Toast.makeText(MainActivity.this, "Upload in progress", Toast.LENGTH_SHORT).show();
                } else {
                    uploadFile();
                }
            }
        });
        mTextViewShowUploads.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openImagesActivity();
            }
        });
    }
    private void openFileChooser() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(intent, PICK_IMAGE_REQUEST);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK
                && data != null && data.getData() != null) {
            mImageUri = data.getData();
            Picasso.with(this).load(mImageUri).into(mImageView);
        }
    }
    private String getFileExtension(Uri uri) {
        ContentResolver cR = getContentResolver();
        MimeTypeMap mime = MimeTypeMap.getSingleton();
        return mime.getExtensionFromMimeType(cR.getType(uri));
    }
    private void uploadFile() {
        if (mImageUri != null) {
            StorageReference fileReference = mStorageRef.child(System.currentTimeMillis()
                    + "." + getFileExtension(mImageUri));
            mUploadTask = fileReference.putFile(mImageUri)
                    .addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                        @Override
                        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                            Handler handler = new Handler();
                            handler.postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    mProgressBar.setProgress(0);
                                }
                            }, 500);

                            Toast.makeText(MainActivity.this, "Upload successful", Toast.LENGTH_LONG).show();
                            Upload upload = new Upload(mEditTextFileName.getText().toString().trim(),
                                    taskSnapshot.getUploadSessionUri().toString());
                            String uploadId = mDatabaseRef.push().getKey();
                            mDatabaseRef.child(uploadId).setValue(upload);
                        }
                    })
                    .addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    })
                    .addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
                        @Override
                        public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
                            double progress = (100.0 * taskSnapshot.getBytesTransferred() / taskSnapshot.getTotalByteCount());
                            mProgressBar.setProgress((int) progress);
                        }
                    });
        } else {
            Toast.makeText(this, "No file selected", Toast.LENGTH_SHORT).show();
        }
    }
    private void openImagesActivity() {
        Intent intent = new Intent(this, ImagesActivity.class);
        startActivity(intent);
    }
}

activity_images.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="8dp">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <TextView
            android:id="@+id/text_view_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:text="Name"
            android:textColor="@android:color/black"
            android:textSize="20sp" />

        <ImageView
            android:id="@+id/image_view_upload"
            android:layout_width="match_parent"
            android:layout_height="300dp" />

    </LinearLayout>

</androidx.cardview.widget.CardView>

image_item.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="8dp">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <TextView
            android:id="@+id/text_view_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:text="Name"
            android:textColor="@android:color/black"
            android:textSize="20sp" />
        <ImageView
            android:id="@+id/image_view_upload"
            android:layout_width="match_parent"
            android:layout_height="300dp" />
    </LinearLayout>
</androidx.cardview.widget.CardView>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:padding="16dp"
    tools:context="ranjan.shashi.firebaseuploadretrieveimages.MainActivity">

    <Button
        android:id="@+id/button_choose_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Choose file" />

    <EditText
        android:id="@+id/edit_text_file_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_toEndOf="@+id/button_choose_image"
        android:hint="Enter file name" />

    <ImageView
        android:id="@+id/image_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/progress_bar"
        android:layout_below="@id/edit_text_file_name"
        android:layout_marginTop="16dp" />

    <ProgressBar
        android:id="@+id/progress_bar"
        style="@style/Widget.AppCompat.ProgressBar.Horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/button_upload"
        android:layout_alignParentStart="true"
        android:layout_marginBottom="16dp" />

    <Button
        android:id="@+id/button_upload"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Upload" />

    <TextView
        android:id="@+id/text_view_show_uploads"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button_upload"
        android:layout_alignTop="@+id/button_upload"
        android:layout_marginStart="25dp"
        android:layout_toEndOf="@+id/button_upload"
        android:gravity="center"
        android:text="Show Uploads"
        android:textSize="16sp" />
</RelativeLayout>

得到一个错误：E / RecyclerView：没有连接适配器；跳过布局

Answer 1

最终解决了该问题，实际上，从Firebase提取的URL中存在问题……上面的代码没有问题。