当单击菜单图标打开NavigationDrawer时，它会崩溃

Question

当我点击图标打开NavigationDrawer时，我的应用程序突然崩溃，我正试图在大约3天内解决这个问题。有人能帮我吗？我正在使用安卓工作室，这是我的第一个应用程序。我的问题是点击应用程序栏上的图标打开NavigationDrawer。

代码：

MainActivity.java
package com.example.chatapp;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import android.content.Intent;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.material.navigation.NavigationView;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
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 com.squareup.picasso.Picasso;
import de.hdodenhof.circleimageview.CircleImageView;
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
Toolbar toolbar;
DrawerLayout drawerLayout;
NavigationView navigationView;
FirebaseAuth mAuth;
FirebaseUser mUser;
DatabaseReference mUserRef;
String profileImageUriV, usernameV;
CircleImageView profileImageHeader;
TextView usernameHeader;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar=findViewById(R.id.app_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Chat App");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu);
mAuth=FirebaseAuth.getInstance();
mUser=mAuth.getCurrentUser();
mUserRef= FirebaseDatabase.getInstance().getReference().child("Users");

drawerLayout=findViewById(R.id.drawerLayout);
navigationView=findViewById(R.id.navView);
View view=navigationView.inflateHeaderView(R.layout.drawer_header);
profileImageHeader=view.findViewById(R.id.profileImage_Header);
usernameHeader=view.findViewById(R.id.usernameHeader);
navigationView.setNavigationItemSelectedListener(this);

}
@Override
protected void onStart() {
super.onStart();
if (mUser==null)
{
SendUserToLoginActivity();
}
else{
mUserRef.child(mUser.getUid()).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists())
{
profileImageUriV=dataSnapshot.child("profileImage").getValue().toString();
usernameV=dataSnapshot.child("username").getValue().toString();
Picasso.get().load(profileImageUriV).into(profileImageHeader);
usernameHeader.setText(usernameV);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(MainActivity.this, "Sorry! Something going wrong", Toast.LENGTH_SHORT).show();
}
});
}
}
private void SendUserToLoginActivity() {
Intent intent=new Intent(MainActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
switch (menuItem.getItemId()){
case R.id.home:
Toast.makeText(this, "Home", Toast.LENGTH_SHORT).show();
break;
case R.id.profile:
Toast.makeText(this, "Profile", Toast.LENGTH_SHORT).show();
break;
case R.id.friend:
Toast.makeText(this, "Friend", Toast.LENGTH_SHORT).show();
break;
case R.id.findFriend:
Toast.makeText(this, "Find Friend", Toast.LENGTH_SHORT).show();
break;
case R.id.chat:
Toast.makeText(this, "Chat", Toast.LENGTH_SHORT).show();
break;
case R.id.logout:
Toast.makeText(this, "Logout", Toast.LENGTH_SHORT).show();
break;
}
return true;
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
if (item.getItemId()==android.R.id.home){
drawerLayout.openDrawer(GravityCompat.START);
return true;
}
return true;
}

}

抽屉_Menu.xml：

<group android:id="@+id/first">
<item android:id="@+id/home"
android:title="Home"
android:icon="@drawable/ic_home"/>
<item android:id="@+id/profile"
android:title="Profile "
android:icon="@drawable/ic_profile"/>
<item android:id="@+id/friend"
android:title="Friend "
android:icon="@drawable/ic_friend"/>
<item android:id="@+id/findFriend"
android:title="Find Friend "
android:icon="@drawable/ic_find_friend"/>
<item android:id="@+id/chat"
android:title="Chat "
android:icon="@drawable/ic_chat"/>

</group>
<group android:id="@+id/second">
<item android:id="@+id/logout"
android:title="Logout "
android:icon="@drawable/ic_logout"/>
</group>

activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="@+id/app_bar"
layout="@layout/main_appbar" />
<EditText
android:id="@+id/inputAddPost"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="16dp"
android:background="@drawable/input_add_post_bg"
android:hint="Post something here :)"
android:paddingLeft="50dp"
android:paddingTop="10dp"
android:paddingRight="10dp"
android:paddingBottom="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/app_bar" />
<ImageView
android:id="@+id/addImagePost"
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_marginStart="8dp"
app:layout_constraintBottom_toBottomOf="@+id/inputAddPost"
app:layout_constraintStart_toStartOf="@+id/inputAddPost"
app:layout_constraintTop_toTopOf="@+id/inputAddPost"
app:srcCompat="@drawable/ic_add_post_image" />
<ImageView
android:id="@+id/send_post_imageView"
android:layout_width="53dp"
android:layout_height="48dp"
android:layout_marginEnd="8dp"
app:layout_constraintBottom_toBottomOf="@+id/inputAddPost"
app:layout_constraintEnd_toEndOf="@+id/inputAddPost"
app:layout_constraintTop_toTopOf="@+id/inputAddPost"
app:srcCompat="@drawable/send_post" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/inputAddPost"
android:background="@color/colorGray"/>
</androidx.constraintlayout.widget.ConstraintLayout>

<com.google.android.material.navigation.NavigationView
android:id="@+id/navView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="@menu/drawer_menu"/>

</androidx.drawerlayout.widget.DrawerLayout>

build.gradle:

implementation 'com.google.firebase:firebase-auth:19.3.0'
implementation 'com.google.firebase:firebase-core:17.3.0'
implementation 'com.google.firebase:firebase-storage:19.1.1'
implementation 'com.firebaseui:firebase-ui-database:6.2.1'
implementation 'com.google.android.material:material:1.0.0'
implementation 'de.hdodenhof:circleimageview:3.1.0'
implementation 'com.squareup.picasso:picasso:2.71828'

Answer 1

我想您可能错过了在"activity_main.xml"中提及DrawerLayout的id，我们的活动通过该id在xml文件中找到布局

android:id="@+id/drawerLayout"

以下是更新后的代码。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="@+id/app_bar"
layout="@layout/main_appbar" />
<EditText
android:id="@+id/inputAddPost"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="16dp"
android:background="@drawable/input_add_post_bg"
android:hint="Post something here :)"
android:paddingLeft="50dp"
android:paddingTop="10dp"
android:paddingRight="10dp"
android:paddingBottom="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/app_bar" />
<ImageView
android:id="@+id/addImagePost"
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_marginStart="8dp"
app:layout_constraintBottom_toBottomOf="@+id/inputAddPost"
app:layout_constraintStart_toStartOf="@+id/inputAddPost"
app:layout_constraintTop_toTopOf="@+id/inputAddPost"
app:srcCompat="@drawable/ic_add_post_image" />
<ImageView
android:id="@+id/send_post_imageView"
android:layout_width="53dp"
android:layout_height="48dp"
android:layout_marginEnd="8dp"
app:layout_constraintBottom_toBottomOf="@+id/inputAddPost"
app:layout_constraintEnd_toEndOf="@+id/inputAddPost"
app:layout_constraintTop_toTopOf="@+id/inputAddPost"
app:srcCompat="@drawable/send_post" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/inputAddPost"
android:background="@color/colorGray"/>
</androidx.constraintlayout.widget.ConstraintLayout>

<com.google.android.material.navigation.NavigationView
android:id="@+id/navView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="@menu/drawer_menu"/>

</androidx.drawerlayout.widget.DrawerLayout>