在MainActivity（以及其他活动中，为简单起见，我们将重点放在此）上，我从FireBase实时数据库中检索了一些项目，我们所讨论的是2-3个适合ListView。加载信息通常需要2-3秒，这似乎很奇怪。
此外，加载图标在此期间未显示，这让我感到困惑。
我正在按照FireBase指示的常规方式检索数据，所以我想知道是什么原因造成的。
编辑-尝试Alex Mamo的建议， 这是Logcat：
FATAL EXCEPTION: main
Process: com.example.guyerez.todotiger, PID: 23964
android.content.res.Resources$NotFoundException: String resource ID #0x0
at android.content.res.Resources.getText(Resources.java:347)
at android.content.res.MiuiResources.getText(MiuiResources.java:97)
at android.widget.TextView.setText(TextView.java:4557)
at com.example.guyerez.todotiger.MainActivity$TaskListHolder.setTaskList(MainActivity.java:464)
at com.example.guyerez.todotiger.MainActivity$1.onBindViewHolder(MainActivity.java:101)
at com.example.guyerez.todotiger.MainActivity$1.onBindViewHolder(MainActivity.java:98)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:122)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6781)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6823)
at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5752)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6019)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3924)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3641)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4194)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:444)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:727)
at android.view.View.layout(View.java:17548)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2384)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2111)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1288)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6359)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:873)
at android.view.Choreographer.doCallbacks(Choreographer.java:685)
at android.view.Choreographer.doFrame(Choreographer.java:621)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:859)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:163)
at android.app.ActivityThread.main(ActivityThread.java:6237)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
这是我的新MainActivity代码
public class MainActivity extends AppCompatActivity {
private static final String CHANNEL_ID = "123";
final Context context = this;
public static final int SIGN_IN = 1;
public static String currentTaskListId;
public static String currentUserId;
private TaskListAdapter mTaskListAdapter;
//TextView that is displayed when the list is empty//
private TextView mEmptyStateTextView;
//The loading indicator //
private View loadingIndicator;
// Firebase instance variables
private FirebaseAuth mFirebaseAuth;
private FirebaseAuth.AuthStateListener mAuthStateListener;
private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mTaskListDatabaseReference;
private ChildEventListener mChildEventListener;
private FirebaseRecyclerAdapter<TaskList, TaskListHolder> firebaseRecyclerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set the content of the activity to use the activity_main.xml layout file - the task lists
setContentView(R.layout.activity_main);
//Create the notification channel
createNotificationChannel();
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
Query query = rootRef.child("users");
// Initialize Firebase components
mFirebaseAuth = FirebaseAuth.getInstance();
mFirebaseDatabase = FirebaseDatabase.getInstance();
FirebaseRecyclerOptions<TaskList> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<TaskList>()
.setQuery(query, TaskList.class)
.build();
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<TaskList, TaskListHolder>(firebaseRecyclerOptions) {
@Override
protected void onBindViewHolder(@NonNull TaskListHolder taskListHolder, int position, @NonNull TaskList blogPost) {
taskListHolder.setTaskList(blogPost);
}
@Override
public TaskListHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.tlist_item, parent, false);
return new TaskListHolder(view);
}
};
recyclerView.setAdapter(firebaseRecyclerAdapter);
//Initialize firebase authentication
mAuthStateListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
// user is signed in
currentUserId=user.getUid();
onSignedInInitialize(user.getUid());
} else {
// user is signed out
onSignedOutCleanup();
startActivityForResult(
AuthUI.getInstance()
.createSignInIntentBuilder()
.setIsSmartLockEnabled(false)
.setAvailableProviders(Arrays.asList(
new AuthUI.IdpConfig.EmailBuilder().build(),
new AuthUI.IdpConfig.GoogleBuilder().build()))
.setTosAndPrivacyPolicyUrls("https://superapp.example.com/terms-of-service.html",
"https://superapp.example.com/privacy-policy.html")
.build(),
SIGN_IN);
}
}
};
//Set and create the FAB and it's action listener
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Get add_list.xml view
LayoutInflater li = LayoutInflater.from(context);
View addTaskListView = li.inflate(R.layout.add_list, null);
//Create the prompt to enable the user to create a new task list
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
context);
// Set add_list.xml as the layout for alertdialog builder
alertDialogBuilder.setView(addTaskListView);
//Set the user input box
final EditText userInput = (EditText) addTaskListView
.findViewById(R.id.edit_list_name);
// Set dialog message
alertDialogBuilder
.setCancelable(false)
.setPositiveButton("Create",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// Get list title from user and create a new task list
//Also fetch the FireBase ID and connect it to the new task list.
String mTaskListId = mTaskListDatabaseReference.push().getKey();
TaskList taskList = new TaskList(userInput.getText().toString(),mTaskListId,0);
mTaskListDatabaseReference.child(mTaskListId).setValue(taskList);
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
dialog.cancel();
}
});
// Create the dialog
final AlertDialog alertDialog = alertDialogBuilder.create();
// Enable create button when input is not empty
userInput.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (charSequence.toString().trim().length() > 0) {
alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(true);
} else {
alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(false);
}
}
@Override
public void afterTextChanged(Editable editable) {
}
});
// Show the dialog
alertDialog.show();
alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(false);
}
});
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == SIGN_IN) {
if (resultCode == RESULT_OK) {
// Sign-in succeeded, set up the UI
Toast.makeText(this, "Signed in!", Toast.LENGTH_SHORT).show();
} else if (resultCode == RESULT_CANCELED) {
// Sign in was canceled by the user, finish the activity
Toast.makeText(this, "Sign in canceled", Toast.LENGTH_SHORT).show();
finish();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.mini_menu,menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.sign_out:
AuthUI.getInstance().signOut(this);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onResume() {
super.onResume();
mFirebaseAuth.addAuthStateListener(mAuthStateListener);
}
@Override
protected void onPause() {
super.onPause();
if (mAuthStateListener != null) {
mFirebaseAuth.removeAuthStateListener(mAuthStateListener);
}
mTaskListAdapter.clear();
// detachDatabaseReadListener();
}
private void onSignedInInitialize(final String userId) {
//Get reference for the task list for the logged in user and attach the database listener
mTaskListDatabaseReference=mFirebaseDatabase.getReference().child("users").child(userId);
// attachDatabaseReadListener();
}
private void onSignedOutCleanup() {
// mTaskListAdapter.clear();
// detachDatabaseReadListener();
}
private void attachDatabaseReadListener() {
if (mChildEventListener == null) {
mChildEventListener = new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
mEmptyStateTextView.setVisibility(View.GONE);
loadingIndicator.setVisibility(View.GONE);
TaskList taskList = dataSnapshot.getValue(TaskList.class);
mTaskListAdapter.add(taskList);
}
public void onChildChanged(DataSnapshot dataSnapshot, String s) {}
public void onChildRemoved(DataSnapshot dataSnapshot) {
if(mTaskListAdapter.isEmpty()){
mEmptyStateTextView.setVisibility(View.VISIBLE);
mEmptyStateTextView.setText("No task lists, add a new one!");
}
}
public void onChildMoved(DataSnapshot dataSnapshot, String s) {}
public void onCancelled(DatabaseError databaseError) {}
};
}
mTaskListDatabaseReference.addChildEventListener(mChildEventListener);
}
private void detachDatabaseReadListener() {
if (mChildEventListener != null) {
mTaskListDatabaseReference.removeEventListener(mChildEventListener);
mChildEventListener = null;
}
}
public static String getCurrentTaskListId() {
return currentTaskListId;
}
public static String getCurrentUserId() {
return currentUserId;
}
/**
* MENU
*/
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo){
if (v.getId() == R.id.task_list_view){
AdapterView.AdapterContextMenuInfo info =(AdapterView.AdapterContextMenuInfo)menuInfo;
menu.add(0,0,0,"Delete");
menu.add(0,1,1,"TEST");
}
}
@Override
public boolean onContextItemSelected(MenuItem menuItem){
AdapterView.AdapterContextMenuInfo info=(AdapterView.AdapterContextMenuInfo)menuItem.getMenuInfo();
TaskList taskListClicked=mTaskListAdapter.getItem(info.position);
Log.d("check","" +taskListClicked.getTitle());
switch (menuItem.getItemId()) {
case 0:
mTaskListDatabaseReference.child(taskListClicked.getId()).removeValue();
mTaskListAdapter.remove(taskListClicked);
Toast.makeText(this, "Task List deleted!", Toast.LENGTH_LONG).show();
break;
case 1:
// Create an explicit intent for an Activity in your app
Intent intent = new Intent(this, TaskActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, CHANNEL_ID)
.setSmallIcon(R.drawable.fui_ic_mail_white_24dp)
.setContentTitle("My notification")
.setContentText("Hello World!")
.setPriority(NotificationCompat.PRIORITY_HIGH)
// Set the intent that will fire when the user taps the notification
.setContentIntent(pendingIntent)
.setAutoCancel(true);
//get the current task list's ID
currentTaskListId=taskListClicked.getId();
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
// notificationId is a unique int for each notification that you must define
notificationManager.notify(0, mBuilder.build());
default:
break;
}
return true;
}
private void createNotificationChannel() {
// Create the NotificationChannel, but only on API 26+ because
// the NotificationChannel class is new and not in the support library
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
CharSequence name = getString(R.string.channel_name);
String description = getString(R.string.channel_description);
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
channel.setDescription(description);
// Register the channel with the system; you can't change the importance
// or other notification behaviors after this
NotificationManager notificationManager = getSystemService(NotificationManager.class);
notificationManager.createNotificationChannel(channel);
}
}
private class TaskListHolder extends RecyclerView.ViewHolder {
private TextView titleTextView, taskNumTextView;
TaskListHolder(View itemView) {
super(itemView);
titleTextView = itemView.findViewById(R.id.list_title);
taskNumTextView = itemView.findViewById(R.id.num_of_tasks);
}
void setTaskList(TaskList taskList) {
String title = taskList.getTitle();
titleTextView.setText(title);
int taskNum = taskList.getTaskNum();
taskNumTextView.setText(taskNum);
}
}
@Override
protected void onStart() {
super.onStart();
firebaseRecyclerAdapter.startListening();
}
@Override
protected void onStop() {
super.onStop();
if (firebaseRecyclerAdapter!= null) {
firebaseRecyclerAdapter.stopListening();
}
}
}
答案 0 :(得分：1)
要解决此问题，请更改以下代码行：
taskNumTextView.setText(taskNum);
到
taskNumTextView.setText(String.valueOf(taskNum));
您传递给setText()方法的参数应该是String类型，而不是int。