Interpreting error messages from logcat in android studio

Question

I am trying to build an app but when I test it, the app crashes before it opens. Looking at the logcat, I get these messages:

2020-09-19 12:51:13.619 5686-5686/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.josullivan.mytestapplication, PID: 5686
java.lang.RuntimeException: Unable to start activity 
ComponentInfo{com.josullivan.mytestapplication/com.josullivan.mytestapplication.MainActivity}: 
android.view.InflateException: Binary XML file line #34 in 
com.josullivan.mytestapplication:layout/activity_main: Binary XML file line #34 in 
com.josullivan.mytestapplication:layout/activity_main: Error inflating class 
com.google.android.material.navigation.NavigationView
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
    at 
android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:223)
    at android.app.ActivityThread.main(ActivityThread.java:7656)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
 Caused by: android.view.InflateException: Binary XML file line #34 in 
com.josullivan.mytestapplication:layout/activity_main: Binary XML file line #34 in 
com.josullivan.mytestapplication:layout/activity_main: Error inflating class 
com.google.android.material.navigation.NavigationView
 Caused by: android.view.InflateException: Binary XML file line #34 in 
com.josullivan.mytestapplication:layout/activity_main: Error inflating class 
com.google.android.material.navigation.NavigationView
 Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Constructor.newInstance0(Native Method)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
    at android.view.LayoutInflater.createView(LayoutInflater.java:852)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:1004)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:532)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
    at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
    at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
    at com.josullivan.mytestapplication.MainActivity.onCreate(MainActivity.java:48)
    at android.app.Activity.performCreate(Activity.java:8000)
    at android.app.Activity.performCreate(Activity.java:7984)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
    at 
android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:223)
    at android.app.ActivityThread.main(ActivityThread.java:7656)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2020-09-19 12:51:13.620 5686-5686/? E/AndroidRuntime: Caused by: android.view.InflateException: 
Couldn't resolve menu item onClick handler onClickHandler in class 
com.josullivan.mytestapplication.MainActivity
    at androidx.appcompat.view.SupportMenuInflater$InflatedOnMenuItemClickListener.<init> 
(SupportMenuInflater.java:255)
    at androidx.appcompat.view.SupportMenuInflater$MenuState.setItem(SupportMenuInflater.java:484)
    at androidx.appcompat.view.SupportMenuInflater$MenuState.addItem(SupportMenuInflater.java:531)
    at androidx.appcompat.view.SupportMenuInflater.parseMenu(SupportMenuInflater.java:207)
    at androidx.appcompat.view.SupportMenuInflater.inflate(SupportMenuInflater.java:129)
    at com.google.android.material.navigation.NavigationView.inflateMenu(NavigationView.java:366)
    at com.google.android.material.navigation.NavigationView.<init>(NavigationView.java:234)
    at com.google.android.material.navigation.NavigationView.<init>(NavigationView.java:121)
        ... 28 more
 Caused by: java.lang.NoSuchMethodException: 
com.josullivan.mytestapplication.MainActivity.onClickHandler [interface android.view.MenuItem]
    at java.lang.Class.getMethod(Class.java:2072)
    at java.lang.Class.getMethod(Class.java:1693)
    at androidx.appcompat.view.SupportMenuInflater$InflatedOnMenuItemClickListener.<init> 
(SupportMenuInflater.java:251)
        ... 35 more

It says towards the end it can't resolve onClickHandler on menu item which I think is causing the issue but I don't know how. My app will have multiple fragments that each will (assuming I can get it working) have multiple canvases to draw shapes with a finger, so I used an onClickHandler to initialize a paintView class in MainActivity.java with the correct custom canvas view so as to draw with a finger on the appropriate view. Do you have any idea why it's causing this issue and how to fix this it? I am new to java coding so, can you explain it to me like I'm 5 years old? Many thanks

MainActivity.java

package com.josullivan.mytestapplication;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;

import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;






import android.view.Menu;
import android.view.MenuInflater;


import com.google.android.material.navigation.NavigationView;

public class MainActivity extends AppCompatActivity implements 
NavigationView.OnNavigationItemSelectedListener {

private DrawerLayout drawer;
private PaintView paintView;


public void onClickHandler(View view) {
    switch (view.getId()) {
        case R.id.nav_chat:
            paintView = (PaintView) findViewById(R.id.paintView1);
            DisplayMetrics metrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(metrics);
            paintView.init(metrics);
            break;
    }
 }


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    drawer = findViewById(R.id.drawer_layout);
    NavigationView navigationView = findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, 
toolbar, R.string.navigation_drawer_open,R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();

    if (savedInstanceState == null) {
        


 getSupportFragmentManager().beginTransaction().replace( 
 R.id.fragment_container, 
 new MessageFragment()).commit();
        navigationView.setCheckedItem(R.id.nav_message);
    }
 }




 @Override
 public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
        case R.id.nav_message:

            
 getSupportFragmentManager().beginTransaction().replace( 
 R.id.fragment_container, new MessageFragment()).commit();
            break;
        case R.id.nav_chat:

            getSupportFragmentManager().beginTransaction().replace( 
R.id.fragment_container, new ChatFragment()).commit();

            
            break;



        case R.id.nav_profile:
            getSupportFragmentManager().beginTransaction().replace( 
R.id.fragment_container, new ProfileFragment()).commit();
            break;
        case R.id.nav_share:
            Toast.makeText(this, "Share", Toast.LENGTH_SHORT).show();
            break;
        case R.id.nav_send:
            Toast.makeText(this, "Send", Toast.LENGTH_SHORT).show();
            break;
    }

    drawer.closeDrawer(GravityCompat.START);

    return true;
}

@Override
public void onBackPressed() {
    if (drawer.isDrawerOpen(GravityCompat.START)){
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}
}

Answer 1

1. There is something wrong in the XML-file corresponding to the MainActivity- check line 34 as the message output suggests "Binary XML file line #34"
2. Can you provide further information? Post the code of MainActivity, do you have the onClickHandler implemented or is it missing?