我有一个我无法解决的问题。我想使用firabase创建一个实时数据库，但是当我转到“本活动”时，系统停止运行。我尽力了，但是我解决不了这个问题。我是一个初学者，所以对我来说很难。请帮忙..
09-01 08:57:57.018 2787-2787/sgtt.celtkituzes_0_1 E/AndroidRuntime: FATAL EXCEPTION: main
Process: sgtt.celtkituzes_0_1, PID: 2787
com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type sgtt.celtkituzes_0_1.AimToAim
at com.google.android.gms.internal.zzaln.zzd(Unknown Source)
at com.google.android.gms.internal.zzaln.zzb(Unknown Source)
at com.google.android.gms.internal.zzaln.zza(Unknown Source)
at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
at com.firebase.ui.database.FirebaseRecyclerAdapter.parseSnapshot(FirebaseRecyclerAdapter.java:147)
at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem(FirebaseRecyclerAdapter.java:136)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:176)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5471)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5504)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4741)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:549)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2906)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15671)
at android.view.ViewGroup.layout(ViewGroup.java:5038)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2086)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1843)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android
登录活动
package sgtt.celtkituzes_0_1;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.backendless.Backendless;
import com.backendless.BackendlessUser;
import com.backendless.async.callback.AsyncCallback;
import com.backendless.exceptions.BackendlessFault;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
public class LoginActivity extends AppCompatActivity {
public static final String APP_ID = "yyy";
public static final String SECRET_KEY = "xxx";
public static final String VERSION = "v1";
// private BroadcastReceiver mRegistrationBroadcastReceiver;
private CheckBox saveLoginCheckBox;
private SharedPreferences loginPreferences;
private SharedPreferences.Editor loginPrefsEditor;
private Boolean saveLogin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
saveLoginCheckBox = (CheckBox)findViewById(R.id.checkBox);
loginPreferences = getSharedPreferences("loginPrefs", MODE_PRIVATE);
loginPrefsEditor = loginPreferences.edit();
final EditText etEmail = (EditText) findViewById(R.id.etEmail);
final EditText etPassword = (EditText) findViewById(R.id.etPassword);
final Button bLogin = (Button) findViewById(R.id.bLogin);
final TextView registerLink = (TextView) findViewById(R.id.tvRegisterHere);
final TextView passwordLink = (TextView) findViewById(R.id.tvRePasswod);
saveLogin = loginPreferences.getBoolean("saveLogin", false);
if (saveLogin == true) {
etEmail.setText(loginPreferences.getString("email", ""));
etPassword.setText(loginPreferences.getString("password", ""));
saveLoginCheckBox.setChecked(true);
}
/* mRegistrationBroadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().endsWith(GCMRegistrationIntentService.REGISTRATION_SUCCESS)){
String token = intent.getStringExtra("token");
Toast.makeText(getApplicationContext(), "GCM token:" + token, Toast.LENGTH_LONG).show();
}else if(intent.getAction().equals(GCMRegistrationIntentService.REGISTRATION_ERROR)){
Toast.makeText(getApplicationContext(), "GCM registration error!!", Toast.LENGTH_LONG).show();
}
}
};*/
/* //Check status on google play device
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext());
if(ConnectionResult.SUCCESS != resultCode){
//Check type of error
if(GooglePlayServicesUtil.isUserRecoverableError(resultCode)){
Toast.makeText(getApplicationContext(), "Google Play Service is not install/enabled in this device!", Toast.LENGTH_LONG).show();
//So notification
GooglePlayServicesUtil.showErrorNotification(resultCode, getApplicationContext());
}else{
Toast.makeText(getApplicationContext(), "This device does not support for Google Play Service!", Toast.LENGTH_LONG).show();
}
}else {
//Start service
Intent itent = new Intent(this, GCMRegistrationIntentService.class);
startService(itent);
}*/
//regisztráció
registerLink.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
Intent registerIntent = new Intent(LoginActivity.this, RegisterActivity.class);
LoginActivity.this.startActivity(registerIntent);
}
});
//jelszó emlékeztető
passwordLink.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String mailforpsw = etEmail.getText().toString();
Backendless.UserService.restorePassword(mailforpsw, new AsyncCallback<Void>()
{
public void handleResponse( Void response )
{
Toast.makeText(getApplicationContext(),"Az új jelszó elküldve a megadott email címre!", Toast.LENGTH_SHORT).show();
}
public void handleFault( BackendlessFault fault )
{
Toast.makeText(getApplicationContext(),"Hiba!", Toast.LENGTH_SHORT).show();
}
});
}
});
//bejelentkezés
bLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(etEmail.getWindowToken(), 0);
String email = etEmail.getText().toString();
String password = etPassword.getText().toString();
if (saveLoginCheckBox.isChecked()) {
loginPrefsEditor.putBoolean("saveLogin", true);
loginPrefsEditor.putString("email", email);
loginPrefsEditor.putString("password", password);
loginPrefsEditor.commit();
} else {
loginPrefsEditor.clear();
loginPrefsEditor.commit();
}
Backendless.UserService.login(email, password, new AsyncCallback<BackendlessUser>() {
@Override
public void handleResponse(BackendlessUser response) {
Toast.makeText(getApplicationContext(),"Sikeres bejelentlezés",Toast.LENGTH_SHORT).show();
Intent loginIntent = new Intent(LoginActivity.this, AimActivity.class);
LoginActivity.this.startActivity(loginIntent);
}
@Override
public void handleFault(BackendlessFault fault) {
Toast.makeText(getApplicationContext(),"Sikertelen bejelentlezés",Toast.LENGTH_SHORT).show();
}
});
}
});
Backendless.initApp(this, APP_ID, SECRET_KEY, VERSION);
}
/*@Override
protected void onResume() {
super.onResume();
Log.w("UserAreaActivity", "onResume");
LocalBroadcastManager.getInstance(this).registerReceiver(mRegistrationBroadcastReceiver, new IntentFilter(GCMRegistrationIntentService.REGISTRATION_SUCCESS));
LocalBroadcastManager.getInstance(this).registerReceiver(mRegistrationBroadcastReceiver, new IntentFilter(GCMRegistrationIntentService.REGISTRATION_ERROR));
}
@Override
protected void onPause() {
super.onPause();
Log.w("UserAreaActivity", "onPause");
LocalBroadcastManager.getInstance(this).unregisterReceiver(mRegistrationBroadcastReceiver);
}*/
}
AimActivity
package sgtt.celtkituzes_0_1;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;
import android.content.SharedPreferences;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
public class AimActivity extends AppCompatActivity implements
GoogleApiClient.OnConnectionFailedListener{
public static class AimViewHolder extends RecyclerView.ViewHolder{
public TextView aimName;
public TextView aimText;
public TextView aimUrl;
public AimViewHolder(View v){
super(v);
aimName = (TextView)itemView.findViewById(R.id.name);
aimText = (TextView)itemView.findViewById(R.id.text);
aimUrl = (TextView)itemView.findViewById(R.id.url);
}
}
public static final String AIMS = "aims";
private RecyclerView mAimRecyclerView;
private LinearLayoutManager mLinearLayoutManager;
public static DatabaseReference mFirebaseDatabaseReference;
private FirebaseRecyclerAdapter<AimToAim, AimViewHolder> mFirebaseAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_aim);
mAimRecyclerView = (RecyclerView)findViewById(R.id.aimRecyclerView);
mLinearLayoutManager = new LinearLayoutManager(this);
mLinearLayoutManager.setStackFromEnd(true);
mAimRecyclerView.setLayoutManager(mLinearLayoutManager);
//Database Initialization
mFirebaseDatabaseReference = FirebaseDatabase.getInstance().getReference();
mFirebaseAdapter = new FirebaseRecyclerAdapter<AimToAim, AimViewHolder>(
AimToAim.class,
R.layout.activity_aim_to_aim,
AimViewHolder.class,
mFirebaseDatabaseReference.child(AIMS)) {
@Override
protected void populateViewHolder(AimViewHolder viewHolder, AimToAim model, int position) {
viewHolder.aimName.setText(model.getName());
viewHolder.aimText.setText(model.getText());
viewHolder.aimUrl.setText(model.getUrl());
}
};
mFirebaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver(){
@Override
public void onItemRangeInserted(int positionStart, int itemCount){
super.onItemRangeInserted(positionStart, itemCount);
int aimCount = mFirebaseAdapter.getItemCount();
int lastVisiblePosition = mLinearLayoutManager.findLastCompletelyVisibleItemPosition();
if (lastVisiblePosition == -1 || (positionStart >= (aimCount -1) && lastVisiblePosition == (positionStart -1))){
mAimRecyclerView.scrollToPosition(positionStart);
}
}
});
mAimRecyclerView.setLayoutManager(mLinearLayoutManager);
mAimRecyclerView.setAdapter(mFirebaseAdapter);
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
}
瞄准
package sgtt.celtkituzes_0_1;
/**
* Created by Storg on 2016.08.27..
*/
public class AimToAim {
private String name;
private String text;
private String url;
public AimToAim(){
}
public AimToAim(String name, String text, String url){
this.name = name;
this.text = text;
this.url = url;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
}
activity_aim xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="sgtt.celtkituzes_0_1.AimActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/aimRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
AimToAim_xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="?android:attr/listPreferredItemHeightLarge">
<TextView
android:id="@+id/name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:text="Name"
android:textAppearance="?android:attr/textAppearanceLarge"
android:paddingLeft="16dp"/>
<TextView
android:id="@+id/text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:text="Address"
android:textAppearance="?android:attr/textAppearanceMedium"
android:paddingLeft="16dp"/>
<TextView
android:id="@+id/url"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:text="url"
android:textAppearance="?android:attr/textAppearanceMedium"
android:paddingLeft="16dp"/>
</LinearLayout>
这可能来晚了，但是解决您的问题的方法是将字段公开。如果要在Firebase上保存数据，还可以在方法中添加@Exclude。并添加@IgnoreExtraProperties：
@IgnoreExtraProperties
public class AimToAim {
public String name;
public String text;
public String url;
//...
public AimToAim(){}
//...
@Exclude
public String getName() {
return name;
}
//...
}
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