我的App运行但数据库没有更新，这是logcat上的错误： 03-02 18：41：43.160 15845-15845 / com.google.firebase.udacity.friendlychat E / BoostFramework：BoostFramework（）：Exception_1 = java.lang.ClassNotFoundException：找不到类＆＃34; com。 qualcomm.qti.Performance＆＃34;在路径上：DexPathList [[]，nativeLibraryDirectories = [/ system / lib64，/ vendor / lib64]] 任何想要解决这个问题的想法，非常感谢。
package com.google.firebase.udacity.friendlychat;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.InputFilter;
import android.text.TextWatcher;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.ProgressBar;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
public static final String ANONYMOUS = "anonymous";
public static final int DEFAULT_MSG_LENGTH_LIMIT = 1000;
private ListView mMessageListView;
private MessageAdapter mMessageAdapter;
private ProgressBar mProgressBar;
private ImageButton mPhotoPickerButton;
private EditText mMessageEditText;
private Button mSendButton;
private String mUsername;
private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mMessagesDatabaseReference;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mUsername = ANONYMOUS;
mFirebaseDatabase = FirebaseDatabase.getInstance();
mMessagesDatabaseReference = mFirebaseDatabase.getReference().child("messages");
// Initialize references to views
mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
mMessageListView = (ListView) findViewById(R.id.messageListView);
mPhotoPickerButton = (ImageButton) findViewById(R.id.photoPickerButton);
mMessageEditText = (EditText) findViewById(R.id.messageEditText);
mSendButton = (Button) findViewById(R.id.sendButton);
// Initialize message ListView and its adapter
List<FriendlyMessage> friendlyMessages = new ArrayList<>();
mMessageAdapter = new MessageAdapter(this, R.layout.item_message, friendlyMessages);
mMessageListView.setAdapter(mMessageAdapter);
// Initialize progress bar
mProgressBar.setVisibility(ProgressBar.INVISIBLE);
// ImagePickerButton shows an image picker to upload a image for a message
mPhotoPickerButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// TODO: Fire an intent to show an image picker
}
});
// Enable Send button when there's text to send
mMessageEditText.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) {
mSendButton.setEnabled(true);
} else {
mSendButton.setEnabled(false);
}
}
@Override
public void afterTextChanged(Editable editable) {
}
});
mMessageEditText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(DEFAULT_MSG_LENGTH_LIMIT)});
// Send button sends a message and clears the EditText
mSendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FriendlyMessage friendlyMessage = new FriendlyMessage(mMessageEditText.getText().toString(), mUsername, null);
// Clear input box
mMessageEditText.setText("");
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_menu, menu);
return true;`enter code here
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return super.onOptionsItemSelected(item);
}
}
我友好的留言课：
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public class FriendlyMessage {
private String text;
private String name;
private String photoUrl;
public FriendlyMessage() {
}
public FriendlyMessage(String text, String name, String photoUrl) {
this.text = text;
this.name = name;
this.photoUrl = photoUrl;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhotoUrl() {
return photoUrl;
}
public void setPhotoUrl(String photoUrl) {
this.photoUrl = photoUrl;
}
}
我有这段代码，但是我收到了＆＃34; AddValueEventListner＆＃34;见下文：
// Read from the database
mFirebaseDatabase.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
// This method is called once with the initial value and again
// whenever data at this location is updated.
String value = dataSnapshot.getValue(String.class);
Log.d(TAG, "Value is: " + value);
}
@Override
public void onCancelled(DatabaseError error) {
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());
}
});