Android Fragment InflateException

Question

I'm trying to communicate with my fragments but the code is not getting agree with me and giving me the error

 E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.aadi.fragmentsdemo, PID: 3435
              java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.aadi.fragmentsdemo/com.example.aadi.fragmentsdemo.MainActivity}: android.view.InflateException: Binary XML file line #28: Error inflating class fragment
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
                  at android.app.ActivityThread.access$800(ActivityThread.java:151)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
                  at android.os.Handler.dispatchMessage(Handler.java:102)
                  at android.os.Looper.loop(Looper.java:135)
                  at android.app.ActivityThread.main(ActivityThread.java:5254)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at java.lang.reflect.Method.invoke(Method.java:372)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
               Caused by: android.view.InflateException: Binary XML file line #28: Error inflating class fragment
                  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
                  at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
                  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
                  at android.app.Activity.setContentView(Activity.java:2145)
                  at com.example.aadi.fragmentsdemo.MainActivity.onCreate(MainActivity.java:12)
                  at android.app.Activity.performCreate(Activity.java:5990)
                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
                  at android.app.ActivityThread.access$800(ActivityThread.java:151) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
                  at android.os.Handler.dispatchMessage(Handler.java:102) 
                  at android.os.Looper.loop(Looper.java:135) 
                  at android.app.ActivityThread.main(ActivityThread.java:5254) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at java.lang.reflect.Method.invoke(Method.java:372) 
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                  at com.example.aadi.fragmentsdemo.Frag.onCreateView(Frag.java:48)
                  at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1255)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1472)
                  at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1691)
                  at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3440)
                  at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
                  at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:378)
                  at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:33)
                  at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79)
                  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:733)
                  at android.view.LayoutInflater.rInflate(LayoutInflater.java:806) 
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:504) 
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:414) 
                  at android.view.LayoutInflater.inflate(LayoutInflater.java:365) 
                  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378) 
                  at android.app.Activity.setContentView(Activity.java:2145) 
                  at com.example.aadi.fragmentsdemo.MainActivity.onCreate(MainActivity.java:12) 
                  at android.app.Activity.performCreate(Activity.java:5990) 
                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278) 
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
                  at android.app.ActivityThread.access$800(ActivityThread.java:151) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
                  at android.os.Handler.dispatchMessage(Handler.java:102) 
                  at android.os.Looper.loop(Looper.java:135) 
                  at android.app.ActivityThread.main(ActivityThread.java:5254) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at java.lang.reflect.Method.invoke(Method.java:372) 
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
Application terminated.

I've already tried all the solutions from StackOverflow's threads but it seems there is something wrong with my code also I'm not an expert and not a beginner so please guys help me out, below are the codes and error

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.aadi.fragmentsdemo.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    android:id="@+id/textView2" />

<fragment
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:name="com.example.aadi.fragmentsdemo.Frage"
    android:id="@+id/fragment2"
    tools:layout="@layout/frag1"
    android:layout_below="@+id/textView2"
    android:layout_centerHorizontal="true" />

<fragment
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:name="com.example.aadi.fragmentsdemo.Frag"
    android:id="@+id/fragment"
    tools:layout="@layout/frag"
    android:layout_below="@+id/fragment2"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="92dp" />
    </RelativeLayout>

second fragment XML file

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

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:inputType="textPersonName"
    android:text="@string/name"
    android:ems="10"
    android:id="@+id/et" />

<Button
    android:text="@string/button"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/btn" />
</LinearLayout>

first fragment java class

package com.adi.fragmentcomm;

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.widget.TextView;

/**
* Created by AADI on 3/21/2017.
 */

public class Frag extends Fragment {
TextView tv;

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

    tv = (TextView) getActivity().findViewById(R.id.textView);
    return v;
}

public void set(String a){
    tv.setText(a);
}
}

second fragment java class

package com.adi.fragmentcomm;


import android.content.Context;
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.widget.Button;
import android.widget.EditText;

/**
* Created by AADI on 3/21/2017.
 */

public class Frag2 extends Fragment {
Button b;
EditText e;
comm ob;

public interface comm{
    void mem(String text);
}


@Override
public void onAttach(Context context) {
    super.onAttach(context);
    try {
        ob = (comm) context;
    }catch (ClassCastException e){
        throw new ClassCastException(context.toString());
    }
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.frag2, container, false);
    b = (Button) getActivity().findViewById(R.id.btn);
    e = (EditText) getActivity().findViewById(R.id.et);
    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ob.mem(e.getText().toString());            }
    });
    return v;
}


}

MainActivity java class

package com.adi.fragmentcomm;

import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Button;
import android.widget.TextView;


public class MainActivity extends FragmentActivity implements Frag2.comm {

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

    @Override
    public void mem(String text) {
        Frag f = (Frag) getSupportFragmentManager().findFragmentById(R.id.fragment);
        f.set(text);

    }
}

Answer 1

Wrong context/view used while referring a view Change code in Frag2 onCreateView()

View v = inflater.inflate(R.layout.frag2, container, false);
b = (Button) v.findViewById(R.id.btn);
e = (EditText) v.findViewById(R.id.et);

Use inflated views object while referring views in it.

Similar correction needed in Frage fragment

Answer 2

Use class instead of name attribute if findFragmentById

<fragment
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.example.aadi.fragmentsdemo.Frage"
android:id="@+id/fragment2"
tools:layout="@layout/frag1"
android:layout_below="@+id/textView2"
android:layout_centerHorizontal="true" />