java - “确保首先调用 FirebaseApp.initializeApp(Context)。” 如何修复此错误?
问题描述
所以我正在尝试使用 Android Studio 创建一个简单的 android 应用程序,当我构建它时看起来很好,但是当我运行应用程序时,我被告知要检查 Logcat,它说 FirebaseApp 没有在我的主程序中初始化活动。所以我添加了
FirebaseApp.initializeApp(this);
到onCreate()
并且它无法解析符号 FirebaseApp 那么我该怎么做才能解决这个问题?
这是我的 Github:
https://github.com/radekkrowicki/Cv4
还有我的主要活动:
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
import com.firebase.ui.auth.AuthUI;
import com.firebase.ui.database.FirebaseListAdapter;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.FirebaseDatabase;
public class MainActivity extends AppCompatActivity {
private static final int SIGN_IN_REQUEST_CODE = 111;
private FirebaseListAdapter<ChatMessage> adapter;
private ListView listView;
private String loggedInUserName = "";
private FirebaseAuth mAuth;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FirebaseApp.initializeApp(this);
//find views by Ids
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
final EditText input = (EditText) findViewById(R.id.input);
listView = (ListView) findViewById(R.id.list);
if (FirebaseAuth.getInstance().getCurrentUser() == null) {
// Start sign in/sign up activity
startActivityForResult(AuthUI.getInstance()
.createSignInIntentBuilder()
.build(), SIGN_IN_REQUEST_CODE);
} else {
// User is already signed in, show list of messages
showAllOldMessages();
}
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (input.getText().toString().trim().equals("")) {
Toast.makeText(MainActivity.this, "Please enter some texts!", Toast.LENGTH_SHORT).show();
} else {
FirebaseDatabase.getInstance()
.getReference()
.push()
.setValue(new ChatMessage(input.getText().toString(),
FirebaseAuth.getInstance().getCurrentUser().getDisplayName(),
FirebaseAuth.getInstance().getCurrentUser().getUid())
);
input.setText("");
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.menu_sign_out) {
AuthUI.getInstance().signOut(this)
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Toast.makeText(MainActivity.this, "You have logged out!", Toast.LENGTH_SHORT).show();
finish();
}
});
}
return true;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == SIGN_IN_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
Toast.makeText(this, "Signed in successful!", Toast.LENGTH_LONG).show();
showAllOldMessages();
} else {
Toast.makeText(this, "Sign in failed, please try again later", Toast.LENGTH_LONG).show();
// Close the app
finish();
}
}
}
private void showAllOldMessages() {
loggedInUserName = FirebaseAuth.getInstance().getCurrentUser().getUid();
Log.d("Main", "user id: " + loggedInUserName);
adapter = new MessageAdapter(this, ChatMessage.class, R.layout.item_in_message,
FirebaseDatabase.getInstance().getReference());
listView.setAdapter(adapter);
}
public String getLoggedInUserName() {
return loggedInUserName;
}
}
我在这里先向您的帮助表示感谢。
解决方案
这一定是同步问题,您正在正确初始化 Firebase:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FirebaseApp.initializeApp(this);
...
...
}
确保再次清理并构建您的项目。
还要确保在文件apply plugin: 'com.google.gms.google-services'
末尾有/app/build.grade
:
dependencies {
...
...
}
apply plugin: 'com.google.gms.google-services'
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