Fragment errors android

Question

I am getting a lot of exceptions in my code. The only reference it points to in my code is at line 24 which is setContentView(R.layout.activity_main). I do not understand why :

07-12 01:36:51.433 3796-3796/com.example.egi.mavisme E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.egi.mavisme, PID: 3796
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.egi.mavisme/com.example.egi.mavisme.MainActivity}: android.view.InflateException: Binary XML file line #49: Binary XML file line #49: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2543)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2609)
        at android.app.ActivityThread.-wrap11(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1465)
        at android.os.Handler.dispatchMessage(Handler.java:111)
        at android.os.Looper.loop(Looper.java:207)
        at android.app.ActivityThread.main(ActivityThread.java:5683)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749)
     Caused by: android.view.InflateException: Binary XML file line #49: Binary XML file line #49: Error inflating class fragment
        at android.view.LayoutInflater.inflate(LayoutInflater.java:539)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
        at android.support.v7.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:467)
        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
        at com.example.egi.mavisme.MainActivity.onCreate(MainActivity.java:24)
        at android.app.Activity.performCreate(Activity.java:6270)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2609) 
        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1465) 
        at android.os.Handler.dispatchMessage(Handler.java:111) 
        at android.os.Looper.loop(Looper.java:207) 
        at android.app.ActivityThread.main(ActivityThread.java:5683) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749) 
     Caused by: android.view.InflateException: Binary XML file line #49: Error inflating class fragment
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:782)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:835)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
        at android.support.v7.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:467) 
        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
        at com.example.egi.mavisme.MainActivity.onCreate(MainActivity.java:24) 
        at android.app.Activity.performCreate(Activity.java:6270) 
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113) 
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) 
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2609) 
        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1465) 
        at android.os.Handler.dispatchMessage(Handler.java:111) 
        at android.os.Looper.loop(Looper.java:207) 
        at android.app.ActivityThread.main(ActivityThread.java:5683) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749) 
     Caused by: java.lang.IllegalStateException: Fragment com.example.egi.mavisme.HeaderNav did not create a view.
        at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3776)
        at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
        at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:395)
        at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:377)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:754)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704) 
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:835) 
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515) 
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
        at android.support.v7.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:467) 
        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
        at com.example.egi.mavisme.MainActivity.onCreate(MainActivity.java:24) 
        at android.app.Activity.performCreate(Activity.java:6270) 
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113) 
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) 
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2609) 
        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1465) 
        at android.os.Handler.dispatchMessage(Handler.java:111) 
        at android.os.Looper.loop(Looper.java:207) 
        at android.app.ActivityThread.main(ActivityThread.java:5683) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749) 

My MainActivity :

public class MainActivity extends AppCompatActivity {
    private TextView mavisTxt;
    private Button testBtn;
    private Fragment navbar = null;


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

    private void initVariables() {
        mavisTxt = (TextView)findViewById(R.id.mavisTxt);
        testBtn = (Button)findViewById(R.id.testBtn);
        navbar = new HeaderNav();

        testBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                hideNavbar();
            }
        });

    }

    private void hideNavbar() {
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.hide(navbar);
        ft.commit();
    }
}

My fragment class :

package com.example.egi.mavisme;


import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.app.Activity;
import android.widget.Button;

public class HeaderNav extends Fragment {
    private static Button homeBtn, optionsBtn, connectionBtn, micBtn, aboutBtn;

    public View onViewCreated(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.navbar, container, false);

        homeBtn = (Button)view.findViewById(R.id.homeBtn);
        optionsBtn = (Button)view.findViewById(R.id.optionsBtn);
        connectionBtn = (Button)view.findViewById(R.id.micBtn);
        micBtn = (Button)view.findViewById(R.id.homeBtn);
        aboutBtn = (Button)view.findViewById(R.id.aboutBtn);

        return view;
    }
}

main activity xml layout:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    android:background="@drawable/background"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="239dp"
        android:layout_height="227dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:contentDescription="mainicon"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.271"
        app:srcCompat="@drawable/main" />

    <TextView
        android:id="@+id/mavisTxt"
        android:layout_width="237dp"
        android:layout_height="177dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:fontFamily="@font/titillium_light"
        android:text="Talk you bastard."
        android:textColor="#ffffff"
        android:textSize="30dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView"
        app:layout_constraintVertical_bias="0.063" />

    <fragment
        android:id="@+id/navbar"
        android:name="com.example.egi.mavisme.HeaderNav"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout="@layout/navbar" />

    <Button
        android:id="@+id/testBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

</android.support.constraint.ConstraintLayout>

here is xml file for fragment:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent" android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView4"
        android:layout_width="match_parent"
        android:layout_height="65dp"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:adjustViewBounds="false"
        android:cropToPadding="false"
        app:srcCompat="@drawable/navbar" />

    <Button
        android:id="@+id/homeBtn"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_centerInParent="@+id/imageView4"
        android:layout_alignTop="@+id/imageView4"
        android:layout_marginTop="6dp"
        android:layout_marginStart="30dp"
        android:background="@drawable/home_icon" />

    <Button
        android:id="@+id/optionsBtn"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_centerInParent="@+id/imageView4"
        android:layout_alignTop="@+id/imageView4"
        android:layout_marginTop="6dp"
        android:layout_marginStart="100dp"
        android:background="@drawable/options_icon" />

    <Button
        android:id="@+id/micBtn"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_alignTop="@+id/homeBtn"
        android:layout_centerHorizontal="true"
        android:background="@drawable/mic_icon" />

    <Button
        android:id="@+id/connectionBtn"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_centerInParent="@+id/imageView4"
        android:layout_alignTop="@+id/imageView4"
        android:layout_marginTop="6dp"
        android:layout_marginStart="240dp"
        android:background="@drawable/con_icon" />

    <Button
        android:id="@+id/aboutBtn"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_centerInParent="@+id/imageView4"
        android:layout_alignTop="@+id/imageView4"
        android:layout_marginTop="6dp"
        android:layout_marginStart="310dp"
        android:background="@drawable/about_icon" />

</RelativeLayout>

I have tried some solutions here in SO, but none of them worked. I am currently still new to android dev so I thought i'd post this here while I research this issue.

Answer 1

I just copied all your code and set up a small sample app. I changed the name of the method onViewCreated() because with the method name from your code plus the @Override annotation the app does not compile (there is a method with that name but it does not take the same parameters). With the correct method name onCreateView() plus @Override, everything works.

(OK, I had to swap all the drawables for colors and I also skipped the font - this may be another error source).

With the wrong method name and without @Override, the code compiles because of course you may have a method by that name - this is syntactically correct Java code.

But now I get the same error like you do. Somewhere in the stacktrace it even says

Caused by: java.lang.IllegalStateException: Fragment com.example.egi.mavisme.HeaderNav did not create a view.

This happens because you do not implement onCreateView(). Because of this, the runtime is unable to tell what your Fragment should look like and there is no View to be added to the layout of MainActivity, which in turn causes the InflateException which you see at the beginning of the crash log in Logcat.

So you should change your method as follows:

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.navbar, container, false);

    homeBtn = (Button)view.findViewById(R.id.homeBtn);
    optionsBtn = (Button)view.findViewById(R.id.optionsBtn);
    connectionBtn = (Button)view.findViewById(R.id.micBtn);
    micBtn = (Button)view.findViewById(R.id.homeBtn);
    aboutBtn = (Button)view.findViewById(R.id.aboutBtn);

    return view;
}

Answer 2

The name of your function is incorrect in HeaderNav. It should be:

public class HeaderNav extends Fragment {
    private static Button homeBtn, optionsBtn, connectionBtn, micBtn, aboutBtn;

    @Override
    public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.navbar, container, false);

        homeBtn = (Button)view.findViewById(R.id.homeBtn);
        optionsBtn = (Button)view.findViewById(R.id.optionsBtn);
        connectionBtn = (Button)view.findViewById(R.id.micBtn);
        micBtn = (Button)view.findViewById(R.id.homeBtn);
        aboutBtn = (Button)view.findViewById(R.id.aboutBtn);

        return view;
    }
}