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java.lang.NullPointerException null object reference viewpager

I am stuck while coding and need help on that.
I am using view binding in my project.
I have unable binding and that is working fine.
I have used same code in my earlier project except view binding and that project was working fine.
Here is my XML
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp"
tools:context=".Home">
<androidx.viewpager.widget.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#id/bottom_navigation" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:menu="#menu/bottom_navigation_menu" />
</RelativeLayout>
Here is my Java code
package com.example.professionals;
public class Home extends AppCompatActivity {
private ActivityHomeBinding Homebinding;
protected ViewPager viewPager;
protected Mypager_Adapter mypager_adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Homebinding = ActivityHomeBinding.inflate(getLayoutInflater());
View view = Homebinding.getRoot();
setContentView(view);
Homebinding.pager.findViewById(R.id.pager);
mypager_adapter = new Mypager_Adapter(this);
viewPager.setAdapter(mypager_adapter);
Homebinding.bottomNavigation.setOnItemSelectedListener(new
NavigationBarView.OnItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.home:
showMsg("Home");
break;
case R.id.profile:
showMsg("Profile");
break;
}
return false;
}
});
}
private void showMsg(String msg) {
Toast toast = Toast.makeText(this, msg, Toast.LENGTH_LONG);
toast.show();
}
}
Here is the error list
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.professionals, PID: 17743
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.professionals/com.example.professionals.Home}: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.viewpager.widget.ViewPager.setAdapter(androidx.viewpager.widget.PagerAdapter)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2473)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2535)
at android.app.ActivityThread.access$1100(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1396)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5582)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.viewpager.widget.ViewPager.setAdapter(androidx.viewpager.widget.PagerAdapter)' on a null object reference
at com.example.professionals.Home.onCreate(Home.java:32)
at android.app.Activity.performCreate(Activity.java:6321)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2535) 
at android.app.ActivityThread.access$1100(ActivityThread.java:154) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1396) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5582) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Thanks in advance for help!

You need to add
viewPager = findViewById<ViewPager>(R.id.pager)
Before this line
viewPager.setAdapter(mypager_adapter);
Edit:
Actually it seems like you're attempting to use ViewBinding as well as regular findViewById, if I were you I'd stick with ViewBinding and delete this line
protected ViewPager viewPager;
Then try this instead
Homebinding.pager.setAdapter(mypager_adapter);

You haven't initialize your ViewPager.
You need initialize your viewPager. For that you have couple of options
Initialize with findViewById before setting adapter.
viewPager = findViewById(R.id.pager)
As you are using view binding would be the good idea
Homebinding.pager.setAdapter(mypager_adapter)

How to correctly use a snackbar in Android

I have created a simple counter application for Android. I have just started using support libraries and just to test it out, I wanted to show a snackbar which says Hello. Here is my code in the MainActivity.java file :
package com.mapsup.counter;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import com.google.android.material.snackbar.Snackbar;
public class MainActivity extends Activity {
long count=0;
TextView tv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
SharedPreferences sp=getApplicationContext().getSharedPreferences("preferences",Context.MODE_PRIVATE);
count=sp.getLong("count",0);
tv=findViewById(R.id.counter);
tv.setText(String.valueOf(count));
//Create and display a snackbar
Snackbar snackbar = Snackbar.make(tv,"Hello",Snackbar.LENGTH_LONG);
snackbar.show();
}
public void increase(View view) {
++count;
tv.setText(String.valueOf(count));
}
public void decrease(View view) {
if(count>0) {
--count;
tv.setText(String.valueOf(count));
}
}
public void reset(View view) {
count=0;
tv.setText("0");
}
#Override
public void onStop() {
super.onStop();
Context ctx=getApplicationContext();
SharedPreferences sp=ctx.getSharedPreferences("preferences",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=sp.edit();
editor.putLong("count",count);
editor.apply();
}
}
Here is the layout main_layout.xml file :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#0031A0"
android:orientation="vertical"
android:padding="20dp"
android:id="#+id/root">
<TextView
android:id="#+id/counter"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="20dp"
android:layout_weight="1"
android:background="#B2FFFFFF"
android:gravity="center"
android:textSize="36sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="increase"
android:text="#string/add"
android:textSize="30sp" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="decrease"
android:text="#string/subt"
android:textSize="30sp" />
</LinearLayout>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="reset"
android:text="#string/reset"
android:textAllCaps="false"
android:textSize="30sp" />
</LinearLayout>
When I am running the app, the app crashes. The logcat shows this as the error message :
2020-02-03 00:20:10.015 12849-12849/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mapsup.counter, PID: 12849
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mapsup.counter/com.mapsup.counter.MainActivity}: android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class <unknown>
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class <unknown>
Caused by: android.view.InflateException: Binary XML file line #26: Error inflating class <unknown>
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:430)
at android.view.LayoutInflater.createView(LayoutInflater.java:645)
at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
at com.google.android.material.snackbar.Snackbar.make(Snackbar.java:164)
at com.mapsup.counter.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:6712)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2677)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
Caused by: java.lang.UnsupportedOperationException: Failed to resolve attribute at index 6: TypedValue{t=0x2/d=0x101009b a=1}
at android.content.res.TypedArray.getColorStateList(TypedArray.java:531)
at android.widget.TextView.<init>(TextView.java:805)
at android.widget.TextView.<init>(TextView.java:727)
at android.widget.TextView.<init>(TextView.java:723)
at java.lang.reflect.Constructor.newInstance0(Native Method) 
at java.lang.reflect.Constructor.newInstance(Constructor.java:430) 
at android.view.LayoutInflater.createView(LayoutInflater.java:645) 
at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58) 
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717) 
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785) 
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727) 
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858) 
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:518) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:426) 
at com.google.android.material.snackbar.Snackbar.make(Snackbar.java:164) 
at com.mapsup.counter.MainActivity.onCreate(MainActivity.java:23) 
at android.app.Activity.performCreate(Activity.java:6712) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2677) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527) 
at android.os.Handler.dispatchMessage(Handler.java:110) 
at android.os.Looper.loop(Looper.java:203) 
at android.app.ActivityThread.main(ActivityThread.java:6251) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924) 
The app runs all fine if I remove the snackbar code.
According to my thinking, creating a snackbar is the same as creating a toast, we just need to replace Toast with Snackbar. Is this correct?
What is my mistake and how to properly use a snackbar?

Please replace tv to rootLayout in Snackbar.make(llRootLayout,"Hello",Snackbar.LENGTH_LONG); as below.
public class MainActivity extends Activity {
long count=0;
TextView tv;|
LinearLayout llRootLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
SharedPreferences sp=getApplicationContext().getSharedPreferences("preferences",Context.MODE_PRIVATE);
count=sp.getLong("count",0);
tv=findViewById(R.id.counter);
llRootLayout=findViewById(R.id.root);
tv.setText(String.valueOf(count));
//Create and display a snackbar
Snackbar snackbar=Snackbar.make(llRootLayout,"Hello",Snackbar.LENGTH_LONG);
snackbar.show();
}
public void increase(View view) {
++count;
tv.setText(String.valueOf(count));
}
public void decrease(View view) {
if(count>0) {
--count;
tv.setText(String.valueOf(count));
}
}
public void reset(View view) {
count=0;
tv.setText("0");
}
#Override
public void onStop() {
super.onStop();
Context ctx=getApplicationContext();
SharedPreferences sp=ctx.getSharedPreferences("preferences",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=sp.edit();
editor.putLong("count",count);
editor.apply();
}
}

android.view.InflateException: Binary XML file line #0: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputLayout

I'm new to Android and starting to develop this app I got these error in Logcat, probably related to the theme applied or maybe to the device I used for testing (API 23). I found similar error in web but I can't understand the reason.
Here is the Logcat:
03-12 16:58:54.453 14745-14745/? E/Zygote: v2
03-12 16:58:55.948 14745-14745/thezone.passwordlocker E/AndroidRuntime: FATAL EXCEPTION: main
Process: thezone.passwordlocker, PID: 14745
java.lang.RuntimeException: Unable to start activity ComponentInfo{thezone.passwordlocker/thezone.passwordlocker.SignupActivity}: android.view.InflateException: Binary XML file line #0: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputLayout
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3319)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415)
at android.app.ActivityThread.access$1100(ActivityThread.java:229)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7331)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: android.view.InflateException: Binary XML file line #0: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputLayout
at android.view.LayoutInflater.inflate(LayoutInflater.java:551)
at android.view.LayoutInflater.inflate(LayoutInflater.java:429)
at android.view.LayoutInflater.inflate(LayoutInflater.java:380)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
at thezone.passwordlocker.SignupActivity.onCreate(SignupActivity.java:25)
at android.app.Activity.performCreate(Activity.java:6904)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3266)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415) 
at android.app.ActivityThread.access$1100(ActivityThread.java:229) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:7331) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
Caused by: android.view.InflateException: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputLayout
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:847)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:855)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
at android.view.LayoutInflater.inflate(LayoutInflater.java:527)
at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:380) 
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287) 
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139) 
at thezone.passwordlocker.SignupActivity.onCreate(SignupActivity.java:25) 
at android.app.Activity.performCreate(Activity.java:6904) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3266) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415) 
at android.app.ActivityThread.access$1100(ActivityThread.java:229) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:7331) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.design.widget.TextInputLayout" on path: DexPathList[[zip file "/data/app/thezone.passwordlocker-1/base.apk"],nativeLibraryDirectories=[/data/app/thezone.passwordlocker-1/lib/arm, /vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at android.view.LayoutInflater.createView(LayoutInflater.java:595)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:776)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716) 
at android.view.LayoutInflater.rInflate(LayoutInflater.java:847) 
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
at android.view.LayoutInflater.rInflate(LayoutInflater.java:855) 
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:527) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:380) 
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287) 
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139) 
at thezone.passwordlocker.SignupActivity.onCreate(SignupActivity.java:25) 
at android.app.Activity.performCreate(Activity.java:6904) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3266) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415) 
at android.app.ActivityThread.access$1100(ActivityThread.java:229) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:7331) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
Suppressed: java.lang.ClassNotFoundException: android.support.design.widget.TextInputLayout
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
... 26 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available
The Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="thezone.passwordlocker">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"/>
<activity android:name=".LinkedActivity"/>
<activity android:name=".LoginActivity" android:theme="#style/AppTheme"/>
<activity android:name=".SignupActivity" android:theme="#style/AppTheme">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
The .java main activity:
package thezone.passwordlocker;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class SignupActivity extends AppCompatActivity {
private static final String TAG = "SignupActivity";
EditText _nameText;
EditText _emailText;
EditText _passwordText;
Button _signupButton;
TextView _loginLink;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signup);
_signupButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
signup();
}
});
_loginLink.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Finish the registration screen and return to the Login activity
finish();
}
});
}
public void signup() {
Log.d(TAG, "Signup");
if (!validate()) {
onSignupFailed();
return;
}
_signupButton.setEnabled(false);
final ProgressDialog progressDialog = new ProgressDialog(SignupActivity.this,
R.style.AppTheme);
progressDialog.setIndeterminate(true);
progressDialog.setMessage("Creating Account...");
progressDialog.show();
String name = _nameText.getText().toString();
String email = _emailText.getText().toString();
String password = _passwordText.getText().toString();
// TODO: Implement your own signup logic here.
new android.os.Handler().postDelayed(
new Runnable() {
public void run() {
// On complete call either onSignupSuccess or onSignupFailed
// depending on success
onSignupSuccess();
// onSignupFailed();
progressDialog.dismiss();
}
}, 3000);
}
public void onSignupSuccess() {
_signupButton.setEnabled(true);
setResult(RESULT_OK, null);
finish();
}
public void onSignupFailed() {
Toast.makeText(getBaseContext(), "Login failed", Toast.LENGTH_LONG).show();
_signupButton.setEnabled(true);
}
public boolean validate() {
boolean valid = true;
String name = _nameText.getText().toString();
String email = _emailText.getText().toString();
String password = _passwordText.getText().toString();
if (name.isEmpty() || name.length() < 3) {
_nameText.setError("at least 3 characters");
valid = false;
} else {
_nameText.setError(null);
}
if (email.isEmpty() || !android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
_emailText.setError("enter a valid email address");
valid = false;
} else {
_emailText.setError(null);
}
if (password.isEmpty() || password.length() < 4 || password.length() > 10) {
_passwordText.setError("between 4 and 10 alphanumeric characters");
valid = false;
} else {
_passwordText.setError(null);
}
return valid;
}
}
The main activity layout XML:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fitsSystemWindows="true">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="56dp"
android:paddingLeft="24dp"
android:paddingRight="24dp">
<ImageView android:src="#mipmap/logo"
android:layout_width="wrap_content"
android:layout_height="72dp"
android:layout_marginBottom="24dp"
android:layout_gravity="center_horizontal" />
<!-- Name Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp">
<EditText android:id="#+id/input_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textCapWords"
android:hint="Name" />
</android.support.design.widget.TextInputLayout>
<!-- Email Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp">
<EditText android:id="#+id/input_email"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:hint="Email" />
</android.support.design.widget.TextInputLayout>
<!-- Password Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp">
<EditText android:id="#+id/input_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:hint="Password"/>
</android.support.design.widget.TextInputLayout>
<!-- Signup Button -->
<android.support.v7.widget.AppCompatButton
android:id="#+id/btn_signup"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:layout_marginBottom="24dp"
android:padding="12dp"
android:text="Create Account"/>
<TextView android:id="#+id/link_login"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="24dp"
android:text="Already a member? Login"
android:gravity="center"
android:textSize="16dip"/>
</LinearLayout>
</ScrollView>
style.xml:
<resources>
<!--
Base application theme, dependent on API level. This theme is replaced
by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
-->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!--
Theme customizations available in newer API levels can go in
res/values-vXX/styles.xml, while customizations related to
backward-compatibility can go here.
-->
</style>
</resources>
Gradle dependecies:
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
defaultConfig {
applicationId "thezone.passwordlocker"
minSdkVersion 21
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

Add the Design Support Library dependency
implementation 'com.android.support:design:26.1.0'
Your layout uses a widget from the library : android.support.design.widget.TextInputLayout

Class not found when unmarshalling: android.support.v7.widget.Toolbar$SavedState

i am using Maps API to create a simple android app and i get a wierd error i can't solve. It usually happens when i rotate my device. I'm using google services 8.4.0
4-23 15:39:47.503 9419-9419/com.licenta.vladut.mmap E/Parcel: Class not found when unmarshalling: android.support.v7.widget.Toolbar$SavedState
java.lang.ClassNotFoundException: android.support.v7.widget.Toolbar$SavedState
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:308)
at android.os.Parcel.readParcelableCreator(Parcel.java:2275)
at android.os.Parcel.readParcelable(Parcel.java:2239)
at android.os.Parcel.readValue(Parcel.java:2146)
at android.os.Parcel.readSparseArrayInternal(Parcel.java:2540)
at android.os.Parcel.readSparseArray(Parcel.java:1868)
at android.os.Parcel.readValue(Parcel.java:2203)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2479)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.Bundle.getBundle(Bundle.java:782)
at com.google.android.gms.maps.internal.ao.a(:com.google.android.gms.alldynamite:74)
at maps.ei.bu.a(Unknown Source)
at maps.ei.n.a(Unknown Source)
at com.google.android.gms.maps.internal.i$a.onTransact(:com.google.android.gms.alldynamite:107)
at android.os.Binder.transact(Binder.java:380)
at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment$zza.onCreateView(Unknown Source)
at com.google.android.gms.dynamic.zza$4.zzb(Unknown Source)
at com.google.android.gms.dynamic.zza.zza(Unknown Source)
at com.google.android.gms.dynamic.zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1230)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2315)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:80)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:733)
at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:276)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:136)
at com.licenta.vladut.mmap.MainActivity.onCreate(MainActivity.java:54)
at android.app.Activity.performCreate(Activity.java:6020)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2259)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947)
at android.app.ActivityThread.access$900(ActivityThread.java:149)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.widget.Toolbar$SavedState" on path: DexPathList[[zip file "/data/data/com.google.android.gms/app_chimera/m/00000000/DynamiteModules-prod.apk"],nativeLibraryDirectories=[/data/data/com.google.android.gms/app_chimera/m/00000000/n/armeabi-v7a, /vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.f
04-23 15:39:47.503 9419-9419/com.licenta.vladut.mmap D/AndroidRuntime: Shutting down VM
04-23 15:39:47.505 9419-9419/com.licenta.vladut.mmap E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.licenta.vladut.mmap, PID: 9419
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.licenta.vladut.mmap/com.licenta.vladut.mmap.MainActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947)
at android.app.ActivityThread.access$900(ActivityThread.java:149)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5292)
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:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:276)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:136)
at com.licenta.vladut.mmap.MainActivity.onCreate(MainActivity.java:54)
at android.app.Activity.performCreate(Activity.java:6020)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2259)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368) 
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947) 
at android.app.ActivityThread.access$900(ActivityThread.java:149) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5292) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703) 
Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v7.widget.Toolbar$SavedState
at android.os.Parcel.readParcelableCreator(Parcel.java:2289)
at android.os.Parcel.readParcelable(Parcel.java:2239)
at android.os.Parcel.readValue(Parcel.java:2146)
at android.os.Parcel.readSparseArrayInternal(Parcel.java:2540)
at android.os.Parcel.readSparseArray(Parcel.java:1868)
at android.os.Parcel.readValue(Parcel.java:2203)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2479)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.Bundle.getBundle(Bundle.java:782)
at com.google.android.gms.maps.internal.ao.a(:com.google.android.gms.alldynamite:74)
at maps.ei.bu.a(Unknown Source)
at maps.ei.n.a(Unknown Source)
at com.google.android.gms.maps.internal.i$a.onTransact(:com.google.android.gms.alldynamite:107)
at android.os.Binder.transact(Binder.java:380)
at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment$zza.onCreateView(Unknown Source)
at com.google.android.gms.dynamic.zza$4.zzb(Unknown Source)
at com.google.android.gms.dynamic.zza.zza(Unknown Source)
at com.google.android.gms.dynamic.zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1230)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2315)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:80)
at android.view.LayoutInf
My MainActivity.java is
package com.licenta.vladut.mmap;
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Status;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
public class MainActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener, OnMapReadyCallback {
GoogleMap mMap;
private static final double BM_LAT = 47.6595076, BM_LNG = 23.5631243;
private Toolbar toolbar;
private GoogleApiClient mGoogleApiClient;
private static final String TAG = "SignInActivity";
private static final int ERROR_DIALOG_REQUEST = 9001;
private static final int RC_SIGN_IN = 9002;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestEmail()
.build();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
.addApi(Auth.GOOGLE_SIGN_IN_API, gso)
.addApi(AppIndex.API).build();
if (checkPlayServices()) {
setContentView(R.layout.activity_map);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
(MainActivity.this).setSupportActionBar(toolbar);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
} else {
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.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.sign_out) {
signOut();
return true;
}
return super.onOptionsItemSelected(item);
}
private void signOut() {
Auth.GoogleSignInApi.signOut(mGoogleApiClient).setResultCallback(
new ResultCallback<Status>() {
#Override
public void onResult(Status status) {
toSignIn();
}
});
}
private void toSignIn() {
Intent i = new Intent(this, SignInActivity.class);
startActivity(i);
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
// An unresolvable error has occurred and Google APIs (including Sign-In) will not
// be available.
Log.d(TAG, getString(R.string.onConnectionFailed) + connectionResult);
}
private boolean checkPlayServices() {
GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
int result = googleAPI.isGooglePlayServicesAvailable(this);
if (result != ConnectionResult.SUCCESS) {
if (googleAPI.isUserResolvableError(result)) {
googleAPI.getErrorDialog(this, result,
ERROR_DIALOG_REQUEST).show();
} else {
Toast.makeText(this, "Nu se poate conecta la Google Play Services!", Toast.LENGTH_SHORT).show();
}
return false;
}
return true;
}
#Override
public void onMapReady(final GoogleMap map) {
this.mMap = map;
gotoLocation(BM_LAT,BM_LNG,18);
}
private void gotoLocation(double lat, double lng, float zoom){
LatLng latLng = new LatLng(lat, lng);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(latLng,zoom);
mMap.moveCamera(update);
}
}
Activity_main.xml is
<?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:layout_width="wrap_content"
android:layout_height="match_parent"
tools:context="com.licenta.vladut.mmap.MainActivity">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar"
/>
</RelativeLayout>
activity_map.xml is
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar"
/>
</fragment>
and finally, toolbar.xml is
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
android:background="?attr/colorPrimary"
android:id="#+id/toolbar"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:minHeight="?attr/actionBarSize"
android:layout_width="match_parent"
android:layout_alignParentStart="true"
android:elevation="4dp"
app:popupTheme="#style/AppTheme.PopupOverlay"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
</android.support.v7.widget.Toolbar>

I didn't like provided solutions as it imposed on my layouts and architecture.
Here's what I did to make it work. If you look at your stacktrace the ClassNotFoundException is coming from the line on GoogleMaps. So if we just fix that, the issue is gone.
GoogleMaps pukes/throw an error when the savedInstanceState has other items in it besides it's own. The solution is to just give GoogleMaps it's own dedicated bundle.
// class property
private static final String KEY_MAP_SAVED_STATE = "mapState";
// class methods
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mapView = findMapView(); // make your own method here
Bundle mapState = (savedInstanceState != null)
? savedInstanceState.getBundle(KEY_MAP_SAVED_STATE): null;
mapView.onCreate(mapState);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Bundle mapState = new Bundle();
mapView.onSaveInstanceState(mapState);
outState.putBundle(KEY_MAP_SAVED_STATE, mapState);
}
One thing to note is I'm not using the SupportMapFragment. I'm using a MapView directly. You may have to extend the SupportMapFragment so you can catch the hook methods and provide a blank/clean bundle

Upon rotation, your SupportMapFragment gets destroyed and recreated. Before it's destroyed, it writes its current state to a Parcel, to be used in restoring its state when recreated. The Fragment's saved state will include the state of its child Views, and since you've nested a Toolbar within it, it attempts to save and restore that, as well. The Toolbar class does not have an inner class SavedState necessary for that, so this process fails when trying to restore the Toolbar instance from the Parcel.
The solution is to not nest the Toolbar - or any other View, for that matter - within the <fragment> element. Instead, pull the <include> out of the <fragment>, and put them both in another ViewGroup; for example, a vertical LinearLayout, or a RelativeLayout.

Changing activity_map.xml to this worked, thanks again Mike.
<?xml version="1.0" encoding="utf-8" ?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar" />
<fragment xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
</fragment>
</RelativeLayout>

I had a similar problem with my custom view and found this solution.
I noticed that this crash occurred when I extended RecyclerView or AppCompatSpinner and needed to save the state. The crash will probably happen for other views as well.
Basically the crash is caused by a bug in AbsSavedState as mentioned here.
And the crash only occurs when the constructor of the SavedState is called without a class loader. It seemed like this was an old issue however I started getting crash reports for Android 9 and 10.
So the fix was to change:
public SavedState(Parcel source) {
super(source);
//...
}
to:
public SavedState(Parcel source) {
super(source, LinearLayoutManager.class.getClassLoader());
//...
}
Edit
I was on the right track, but then I was looking at some Android code and found out that there was actually a constructor missing that caused the crash. So I had the following constructor for the SavedState:
SavedState(Parcel in)
{
super(in);
//...
}
And I needed to add the following:
#RequiresApi(Build.VERSION_CODES.N)
SavedState(Parcel in, ClassLoader loader)
{
super(in, loader);
//...
}
And then I needed to change the creator:
public static final Creator<SavedState> CREATOR = new ClassLoaderCreator<SavedState>()
{
#Override
public SavedState createFromParcel(Parcel source, ClassLoader loader)
{
return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ? new SavedState(source, loader) : new SavedState(source);
}
#Override
public SavedState createFromParcel(Parcel source)
{
return createFromParcel(source, null);
}
public SavedState[] newArray(int size)
{
return new SavedState[size];
}
};

java.lang.IllegalStateException: cannot find button's onClick method in Android Studio

I am building an app named Ping in Android Studio. So far my activities are LoginActivity ProfileActivity and Timeline. My issue is that a button in the layout corresponding to the Timeline activity has an onClick method that isn't working. When the button is clicked, the emulator gives the "Unfortunatley, Ping has stopped." I'm defining the buttons and onClick methods the same way I have for other buttons whose functions are working, just this one does not seem to work. I'm receiving an error saying the method can't be found, but I've written the method in the corresponding activity. Here is the logcat:
04-30 10:40:08.727 2075-2075/com.ping_social.www.ping E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.ping_social.www.ping, PID: 2075
java.lang.IllegalStateException: Could not find a method onProfilePress(View) in the activity class android.view.ContextThemeWrapper for onClick handler on view class android.widget.Button with id 'profileButton'
at android.view.View$1.onClick(View.java:4007)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
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.NoSuchMethodException: onProfilePress [class android.view.View]
at java.lang.Class.getMethod(Class.java:664)
at java.lang.Class.getMethod(Class.java:643)
at android.view.View$1.onClick(View.java:4000)
            at android.view.View.performClick(View.java:4780)
            at android.view.View$PerformClick.run(View.java:19866)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5257)
            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)
Here is my Timeline activity class:
package com.ping_social.www.ping;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class TimeLine extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_time_line);
/*print log that shows we've got here*/
Log.i("LoginActivity", "Layout has been set");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_time_line, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/*called when user presses the Log in button*/
public void onProfilePress(View view){
/*Log the button press*/
Log.i("TimeLine", "Has reached the onProfilePress method");
Intent intent = new Intent(this, ProfileActivity.class);
startActivity(intent);
}
}
And here is my Timeline layout xml code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:theme="#style/GeneralTheme"
tools:context="com.ping_social.www.ping.TimeLine">
<TextView android:text="#string/no_pings" android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30sp"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:textIsSelectable="false"
android:textColor="#color/PING_TOP_BAR_RED"
android:id="#+id/textView4" />
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="60dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/timeline_button"
android:id="#+id/timelineButton"
android:textColor="#color/PING_TOP_BAR_RED"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/new_ping_button"
android:id="#+id/newPingButton"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/activity_button"
android:id="#+id/activityButton"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/profile_button"
android:id="#+id/profileButton"
android:layout_weight="1"
android:onClick="onProfilePress"/>
</LinearLayout>
</RelativeLayout>
I'm pretty positive there are not spelling issues, and there are also no other buttons that share the same ID or methods that share the same name. Been stuck on this for a few days, any help is very much appreciated!

Ok, so I made my own test. I've put together a basic relative layout with a single button, put android:theme="#style/AppTheme" in it, and a button - app crashed with the same error. Then I removed android:theme attribute - onclick event fired as it should.
All the same happened when I used AppCompatActivity instead of now-deprecated ActionBarActivity.
It's hard for me to say why it doesn't work with android:theme. It's one of Lollipop's features, but I tried to launch in on API 5.0 emulator. The article states that currently this attribute is only supported for android.support.v7.widget.Toolbar.