我正在使用var Query2 =
from b in Books
orderby b.BookPubid
group b.BookPubid by b.BookPubid into g
select new
{
PublisherID = g.Key,
TotalBooks = g.Count()
};
和recyclerView来检索图像，但不幸的是我遇到了此Firebase错误
cardView这是我的模型课：
Process: com.edu.hilmi.demoopencv, PID: 6939
com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.edu.hilmi.demoopencv.Sample
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertBean(com.google.firebase:firebase-database@@16.1.0:423)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.deserializeToClass(com.google.firebase:firebase-database@@16.1.0:214)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertToCustomClass(com.google.firebase:firebase-database@@16.1.0:79)
at com.google.firebase.database.DataSnapshot.getValue(com.google.firebase:firebase-database@@16.1.0:212)
at com.edu.hilmi.demoopencv.SampleList$1.onDataChange(SampleList.java:55)
at com.google.firebase.database.core.ValueEventRegistration.fireEvent(com.google.firebase:firebase-database@@16.1.0:75)
at com.google.firebase.database.core.view.DataEvent.fire(com.google.firebase:firebase-database@@16.1.0:63)
at com.google.firebase.database.core.view.EventRaiser$1.run(com.google.firebase:firebase-database@@16.1.0:55)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:150)
at android.app.ActivityThread.main(ActivityThread.java:5408)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:964)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
这是上传活动
public class Sample
{
private String SampleID;
private String SampleDate;
private String SampleTime;
private String SampleLocation;
private String SampleImageUrl;
public Sample(){}
public Sample(String sampleID, String sampleDate, String sampleTime, String sampleLocation, String sampleImageUrl) {
SampleID = sampleID;
SampleDate = sampleDate;
SampleTime = sampleTime;
SampleLocation = sampleLocation;
SampleImageUrl = sampleImageUrl;
}
public String getSampleID()
{
return SampleID;
}
public String getSampleImageUrl()
{
return SampleImageUrl;
}
public String getSampleDate()
{
return SampleDate;
}
public String getSampleTime()
{
return SampleTime;
}
public String getSampleLocation()
{
return SampleLocation;
}
public void setSampleID(String sampleID) {
SampleID = sampleID;
}
public void setSampleDate(String sampleDate) {
SampleDate = sampleDate;
}
public void setSampleTime(String sampleTime) {
SampleTime = sampleTime;
}
public void setSampleLocation(String sampleLocation) {
SampleLocation = sampleLocation;
}
public void setSampleImageUrl(String sampleImageUrl) {
SampleImageUrl = sampleImageUrl;
}
}
这是检索图像和其他数据的活动
public void addSample() {
if (FilePathUri != null) {
progressDialog.setTitle("Image is Uploading...");
progressDialog.show();
final StorageReference storageReference2nd = storageReference.child(Storage_Path + System.currentTimeMillis() + "." + GetFileExtension(FilePathUri));
storageReference2nd.putFile(FilePathUri)
.addOnSuccessListener(new OnSuccessListener < UploadTask.TaskSnapshot > () {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
Uri downloadUrl = FilePathUri;
String usableUrl = downloadUrl.toString();
String sampleID = SamID.getText().toString().trim();
String sampleDate = DateText.getText().toString().trim();
String sampleTime = TimeText.getText().toString().trim();
String sampleLocation = LocText.getText().toString().trim();
progressDialog.dismiss();
Toast.makeText(getApplicationContext(), "Image Uploaded Successfully ", Toast.LENGTH_LONG).show();
@SuppressWarnings("VisibleForTests")
Sample sample = new Sample(sampleID, sampleDate, sampleTime, sampleLocation, usableUrl);
databaseReference.child(sampleID).setValue(sample);
SamID.setText("");
DateText.setText("");
TimeText.setText("");
LocText.setText("");
Intent intent = new Intent(RegisterSample.this, SampleList.class);
startActivity(intent);
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception exception) {
progressDialog.dismiss();
Toast.makeText(RegisterSample.this, exception.getMessage(), Toast.LENGTH_LONG).show();
}
})
.addOnProgressListener(new OnProgressListener < UploadTask.TaskSnapshot > () {
@Override
public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
// Setting progressDialog Title.
progressDialog.setTitle("Image is Uploading...");
}
});
这是适配器类
public class SampleList extends AppCompatActivity
{
DatabaseReference mRef;
StorageReference storageRef;
RecyclerView recyclerView;
ArrayList<Sample> list;
SampleListAdapter sampleListAdapter;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sample_list);
if (getSupportActionBar() != null)
getSupportActionBar().setTitle("Sample List");
recyclerView = findViewById(R.id.ImgViewer);
recyclerView.setHasFixedSize(true);
LinearLayoutManager manager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(manager);
recyclerView.setHasFixedSize(true);
//storageRef = FirebaseStorage.getInstance().getReference().child("Sample_images/");
mRef = FirebaseDatabase.getInstance().getReference().child("Samples");
mRef.addValueEventListener(new ValueEventListener()
{
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot)
{
list = new ArrayList<Sample>();
for(DataSnapshot dataSnapshot1: dataSnapshot.getChildren())
{
Sample s= dataSnapshot1.getValue(Sample.class);
list.add(s);
}
sampleListAdapter = new SampleListAdapter(SampleList.this,list);
recyclerView.setAdapter(sampleListAdapter);
sampleListAdapter.notifyDataSetChanged();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError)
{
Toast.makeText(SampleList.this, "Opsss.... Something is wrong", Toast.LENGTH_SHORT).show();
}
});
}
}
图片应显示在public class SampleListAdapter extends RecyclerView.Adapter < SampleListAdapter.ImageViewHolder > {
private Context mContext;
private List < Sample > mSample;
public SampleListAdapter(Context context, List < Sample > samples) {
mContext = context;
mSample = samples;
}
@NonNull
@Override
public ImageViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
View v = LayoutInflater.from(mContext).inflate(R.layout.activity_sample_list_item, viewGroup, false);
return new ImageViewHolder(v);
}
@Override
public void onBindViewHolder(@NonNull ImageViewHolder imageViewHolder, int position) {
Sample sample = mSample.get(position);
imageViewHolder.textViewID.setText(sample.getSampleID());
Picasso.get()
.load(sample.getSampleImageUrl())
.placeholder(R.drawable.photo)
.fit()
.centerInside()
.into(imageViewHolder.imageView);
}
@Override
public int getItemCount() {
return mSample.size();
}
public class ImageViewHolder extends RecyclerView.ViewHolder {
TextView textViewID;
ImageView imageView;
ImageViewHolder(View itemView) {
super(itemView);
textViewID = itemView.findViewById(R.id.text_view_id);
imageView = itemView.findViewById(R.id.image_view_upload);
}
}
}
和cardView