我试图从数据库中检索值以显示在视图上，但我现在正在崩溃
致命的例外：主要 过程：com.example.ahmad.carrental，PID：15975 com.google.firebase.database.DatabaseException：无法将java.lang.String类型的值转换为long 在com.google.android.gms.internal.zzear.zzb（未知来源） 在com.google.android.gms.internal.zzear.zza（未知来源） 在com.google.android.gms.internal.zzear.zzb（未知来源） 在com.google.android.gms.internal.zzeas.zze（未知来源） 在com.google.android.gms.internal.zzear.zzb（未知来源） 在com.google.android.gms.internal.zzear.zza（未知来源） 在com.google.firebase.database.DataSnapshot.getValue（未知来源） 在com.example.ahmad.carrental.Utilities.FirebaseUtilities.getCarData（FirebaseUtilities.java:178） at com.example.ahmad.carrental.CarPost.CreatePostActivity $ 1 $ 1.onDataChange（CreatePostActivity.java:100） 在com.google.android.gms.internal.zzduz.zza（未知来源） 在com.google.android.gms.internal.zzdwu.zzbvb（未知来源） 在com.google.android.gms.internal.zzdxa.run（未知来源） 在android.os.Handler.handleCallback（Handler.java:761） 在android.os.Handler.dispatchMessage（Handler.java:98） 在android.os.Looper.loop（Looper.java:156） 在android.app.ActivityThread.main（ActivityThread.java:6605） at java.lang.reflect.Method.invoke（Native Method） 在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:999） 在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:889）
课程如下
汽车模型
public class Car {
private String brand;
private String id;
private int price;
private String model;
private long distance;
private String status;
private String picture;
private String location;
private String description;
public Car() {
}
public Car(String brand, String id, int price, String model, long distance, String status, String picture, String location, String description) {
this.brand = brand;
this.id = id;
this.price = price;
this.model = model;
this.distance = distance;
this.status = status;
this.picture = picture;
this.location = location;
this.description = description;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public long getDistance() {
return distance;
}
public void setDistance(long distance) {
this.distance = distance;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getPicture() {
return picture;
}
public void setPicture(String picture) {
this.picture = picture;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}
用户模型
public class User {
private String email;
private String id;
private String name;
private int phonenumber;
public User(String email, String id, String name,int phonenumber) {
this.email = email;
this.id = id;
this.name = name;
this.phonenumber = phonenumber;
}
public User(){
}
public int getPhonenumber() {
return phonenumber;
}
public void setPhonenumber(int phonenumber) {
this.phonenumber = phonenumber;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
数据库查询功能
public Car getCarData(DataSnapshot dataSnapshot) {
Log.i(TAG,"getCardData: Getting car data from database");
Car data = new Car();
for(DataSnapshot ds :dataSnapshot.getChildren()){
if(ds.getKey().equals(context.getString(R.string.dbname_car_post))){
try{
data.setId(ds.child(userID).getValue(Car.class).getId());
data.setBrand(ds.child(userID).getValue(Car.class).getBrand());
data.setDescription(ds.child(userID).getValue(Car.class).getDescription());
data.setModel(ds.child(userID).getValue(Car.class).getModel());
data.setDistance(ds.child(userID).getValue(Car.class).getDistance());
data.setPicture(ds.child(userID).getValue(Car.class).getPicture());
data.setStatus(ds.child(userID).getValue(Car.class).getStatus());
data.setLocation(ds.child(userID).getValue(Car.class).getLocation());
data.setPrice(ds.child(userID).getValue(Car.class).getPrice());
}catch (NullPointerException e){
Log.d(TAG, "getCarData: NullPointerException : " + e.getMessage());
}
}
}
return data;
}
我从
中检索数据的活动CreateCarPost活动
public class CreatePostActivity extends AppCompatActivity implements CreatePostView,AdapterView.OnItemSelectedListener{
//Activity Tag
private static final String TAG ="CreateCarPost";
//Spinners
Spinner statusSpinner;
Spinner brandSpinner;
//Adapter of spinners
ArrayAdapter mArrayAdapter;
ArrayAdapter mArrayAdapter2;
//views
private TextView tvDistance;
private EditText etDistance;
private AutoCompleteTextView etCarLocation;
private CircleImageView civPicture;
private EditText etPrice;
private EditText etDescription;
private EditText etModel;
private ImageView checkButton;
//Strings
private String carLoactionStr;
private String carBrandStr;
private String carStatusStr;
//layout containg the views
private LinearLayout layoutContainer;
//To adjust dynamic views margins
LinearLayout.LayoutParams layoutParamsTv,layoutParamsEt;
//Firebase
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthStateListener;
private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mDatabaseReference;
private ValueEventListener singleValueEventListener;
private FirebaseUtilities mFirebaseUtilities;
Context mContext;
CreatePostPresenter createPostPresenter;
private Car car;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_post);
initialization();
setupFirebaseAuth();
setUpLocationSpinner();
//Assigning Car object with its data from database.
io.reactivex.Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(ObservableEmitter emitter) throws Exception {
singleValueEventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
car = mFirebaseUtilities.getCarData(dataSnapshot);
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG, "CANCELLED.");
}
};
mDatabaseReference.addValueEventListener(singleValueEventListener);
}
}).unsubscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe();
checkButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
createPostPresenter.onSaveChanges(car);
}
});
}
//initalizing everything necessary here
public void initialization(){
mContext = getApplicationContext();
createPostPresenter = new CreatePostPresenter(this,this);
//Adapter set up for spinners
mArrayAdapter2 = ArrayAdapter.createFromResource(this,R.array.car_brands,android.R.layout.simple_spinner_item);
mArrayAdapter = ArrayAdapter.createFromResource(this,R.array.car_status_array,android.R.layout.simple_spinner_item);
//Status spinner set up
statusSpinner = findViewById(R.id.createPostCarStatusSpinner_ID);
statusSpinner.setAdapter(mArrayAdapter);
statusSpinner.setOnItemSelectedListener(this);
//Brand spinner set up
brandSpinner = findViewById(R.id.createPostCarBrandSpinner_ID);
brandSpinner.setAdapter(mArrayAdapter2);
brandSpinner.setOnItemSelectedListener(this);
layoutContainer = findViewById(R.id.createPostLinearLayout_ID);
tvDistance = new TextView(this);
tvDistance.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
tvDistance.setText("Distance Travelled");
etDistance = new EditText(this);
etDistance.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
//margin settings editText
layoutParamsEt = (LinearLayout.LayoutParams)etDistance.getLayoutParams();
layoutParamsEt.setMargins(0,10,0,0);
etDistance.setLayoutParams(layoutParamsEt);
//margin settings textView
layoutParamsTv = (LinearLayout.LayoutParams)tvDistance.getLayoutParams();
layoutParamsTv.setMargins(0,10,0,0);
tvDistance.setLayoutParams(layoutParamsTv);
etCarLocation = findViewById(R.id.createPostCarLocation_ID);
etDescription = findViewById(R.id.createPostCarDes_ID);
etPrice = findViewById(R.id.createPostCarPrice_ID);
etModel = findViewById(R.id.createPostCarModel_ID);
checkButton = findViewById(R.id.check_ID);
mFirebaseUtilities = new FirebaseUtilities(this);
}
private void setUpLocationSpinner() {
ArrayAdapter<String> listOfCities = new ArrayAdapter<>(getBaseContext(),
android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.TR_cities));
//--- to ensure user is restricted to selections from drop-down menu
etCarLocation.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
carLoactionStr = etCarLocation.getAdapter().getItem(position).toString();
}
});
etCarLocation.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
for (int i = 0; i < etCarLocation.getAdapter().getCount(); i++) {
if (etCarLocation.getText().toString().equals(etCarLocation.getAdapter().getItem(i))) {
carLoactionStr = etCarLocation.getAdapter().getItem(i).toString();
} else
carLoactionStr = null;
}
}
@Override
public void afterTextChanged(Editable s) {
}
});
//start autocomplete after 1 letter
etCarLocation.setThreshold(1);
etCarLocation.performCompletion();
etCarLocation.setAdapter(listOfCities);
}
/**
* Listener for car status spinner
* @param parent
* @param view
* @param position
* @param id
*/
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Spinner spinner = (Spinner)parent;
if(spinner.getId() == R.id.createPostCarStatusSpinner_ID){
TextView textView = (TextView) view;
carStatusStr = textView.getText().toString();
addDynamicViews(position);
}
else if(spinner.getId() == R.id.createPostCarBrandSpinner_ID){
TextView textView = (TextView) view;
carBrandStr = textView.getText().toString();
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
/**
* Dynamic views creation done by handling user spinner selection for first hand or second hand car status.
*@param position: position of selected value from spinner
*/
public void addDynamicViews(int position){
if(position == 1){
layoutContainer.addView(tvDistance);
layoutContainer.addView(etDistance);
}
else if(position == 0){
mFirebaseUtilities.removeNodeDynamically();
layoutContainer.removeView(tvDistance);
layoutContainer.removeView(etDistance);
}
}
@Override
public void setBrand(String brand) {
}
@Override
public void setPrice(int price) {
}
@Override
public void setLocation(String location) {
}
@Override
public void setDescription(String description) {
}
@Override
public void setModel(String model) {
}
@Override
public void setDistance(long distance) {
}
@Override
public void setStatus(String status) {
}
@Override
public void setPicture(String picture) {
}
@Override
public String getBrand() {
return carBrandStr;
}
@Override
public String getDescription() {
return etDescription.getText().toString();
}
@Override
public String getLocation() {
return carLoactionStr;
}
@Override
public String getModel() {
return etModel.getText().toString();
}
@Override
public String getStatus() {
return carStatusStr;
}
@Override
public String getPicture() {
return null;
}
@Override
public int getPrice() {
String priceViewTemp = etPrice.getText().toString();
if (priceViewTemp.equals("")) {
return 0;
} else {
return Integer.valueOf(etPrice.getText().toString());
}
}
@Override
public long getDistance() {
String distanceViewTemp = etDistance.getText().toString();
if (distanceViewTemp.equals("")) {
return 0;
} else {
return Integer.valueOf(etDistance.getText().toString());
}
}
/*************************************** Firebase *******************************************/
private void setupFirebaseAuth() {
mAuth = FirebaseAuth.getInstance();
mFirebaseDatabase = FirebaseDatabase.getInstance();
mDatabaseReference = mFirebaseDatabase.getReference();
mAuthStateListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
//User is signed in
Log.d(TAG, "onAuthStateChanged: user signed in : " + user.getUid());
} else {
//User is signed out
Log.d(TAG, "onAuthStateChanged: user signed out");
}
}
};
mDatabaseReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
@Override
public void onPause() {
super.onPause();
if (singleValueEventListener != null) {
mDatabaseReference.removeEventListener(singleValueEventListener);
}
}
@Override
public void onResume(){
super.onResume();
mDatabaseReference.addListenerForSingleValueEvent(singleValueEventListener);
}
}
Firebase结构
答案 0 :(得分：0)
Haven没有读过多少，但我第一次注意到了这里。
for(DataSnapshot ds :dataSnapshot.getChildren()){
if(ds.getKey().equals(context.getString(R.string.dbname_car_post))){
try{ }
您尝试检索的密钥是对象。所以我建议我们首先将它转换为字符串，然后在此处进行采样。
for(DataSnapshot ds :dataSnapshot.getChildren()){
Object myKey=ds.getKey;
if(myKey.toString().equals(context.getString(R.string.dbname_car_post))){
try{ }
}}
让我知道接下来会发生什么！