由 android 工作室制作的导航抽屉：android.view.InflateException：错误充气 class 片段

Question

I am a complete beginner in android studio with java and I have run across this error which seems to be very frequent here. I have seen solutions but nothing has helped so far. In my code I have created a navigation drawer using the already made one from android studio. When I try to run the app I get:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.covidmobileapp/com.example.covidmobileapp.MainActivity}: android.view.InflateException: Binary XML file line #15 in com.example.covidmobileapp:layout/activity_main: Binary XML file line #20 in com.example.covidmobileapp:layout/content_main: Error inflating class fragment

Which seems to spot errors in 2 xml files I have: activity_main.xml and content_main.xml

Goind down the stack trace it seems that the error hits when the app view is created

at com.example.covidmobileapp.MainActivity.onCreate(MainActivity.java:55)

This is my code for the files above:

MainActivity.java

package com.example.covidmobileapp;

import android.os.Bundle;
import android.view.View;
import android.view.Menu;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.navigation.NavigationView;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.AppCompatActivity;


import com.example.covidmobileapp.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {



    private AppBarConfiguration mAppBarConfiguration;
    private ActivityMainBinding binding;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        setSupportActionBar(binding.appBarMain.toolbar);
        binding.appBarMain.fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
        DrawerLayout drawer = binding.drawerLayout;
        NavigationView navigationView = binding.navView;
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow , R.id.nav_homepage)
                .setDrawerLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);

        setContentView(R.layout.activity_main);


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }





}

content_main.xml I have commented the line where the fragment error hits

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/app_bar_main">

    <fragment
        android:id="@+id/nav_host_fragment_content_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" //this is where the fragment error hits 
  />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml I have also commented where the error is here

<?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/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        android:id="@+id/app_bar_main"
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" /> //this is where error for activity_main is 

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />
</androidx.drawerlayout.widget.DrawerLayout>

I would appreciate your help as this is really frustrating. If more info is needed I will upload it.

Answer 1

I think you should declare:

    NavigationView leftNavigationView;

in your main activity and get you nav view in on create method:

        leftNavigationView = findViewById(R.id.nav_view);
        setLeftNavigationView();

Then you havae to use setNavigationItemSelectedListener. You can create a method like this:

private void setLeftNavigationView() {
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this,
            drawerLayout,
            toolbar,
            R.string.navigation_drawer_open,
            R.string.navigation_drawer_close);
    drawerLayout.addDrawerListener(toggle);
    toggle.syncState();

    leftNavigationView.setNavigationItemSelectedListener(item -> {

        Fragment selectedFragment = null;
        switch (item.getItemId()) {
            case R.id.nav_yourFragment:
                selectedFragment = new YourFragment();
                drawerLayout.closeDrawer(GravityCompat.START);
                break;
    }
getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.fragment_container, selectedFragment).addToBackStack("tag")
                .commit();
        return true;
});

and so on. R.id.nav_yourFragment is your item from your menu Also you have to put a FrameLayout container in your xml file:

        <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

I hope this is useful for you