Приложение моментально останавливается при попытке запуска

Я новичок в Android Studio,написал простенький мессенджер на Firebase, при сборке проекта всё нормально, при запуске на виртуалке сразу крашиться, при запуске на реальном устройстве выполняет часть кода (запись аккаунта для Firebase) и перестаёт работать.Всю голову сломал, ничего не работает. Вот код

Mainactivity.java

public class MainActivity extends AppCompatActivity {
    private FirebaseListAdapter<ChatMessage> adapter;

    private static final int SIGN_IN_REQUEST_CODE =999 ;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        if (FirebaseAuth.getInstance().getCurrentUser() == null) {
            // Start sign in/sign up activity
            startActivityForResult(
                    AuthUI.getInstance()
                            .createSignInIntentBuilder()
                            .build(),
                    SIGN_IN_REQUEST_CODE
            );
        } else {
            // User is already signed in. Therefore, display
            // a welcome Toast
            Toast.makeText(this,
                    "Welcome " + FirebaseAuth.getInstance()
                            .getCurrentUser()
                            .getDisplayName(),
                    Toast.LENGTH_LONG)
                    .show();

            // Load chat room contents
            displayChatMessages();
        }

        setContentView(R.layout.activity_main);


        FloatingActionButton fab =
                (FloatingActionButton)findViewById(R.id.fab);

        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText input = (EditText)findViewById(R.id.input);

                // Read the input field and push a new instance
                // of ChatMessage to the Firebase database
                FirebaseDatabase.getInstance()
                        .getReference()
                        .push()
                        .setValue(new ChatMessage(input.getText().toString(),
                                FirebaseAuth.getInstance()
                                        .getCurrentUser()
                                        .getDisplayName())
                        );

                // Clear the input
                input.setText("");
            }
        });


    }

    private void displayChatMessages() {


    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode,
                                    Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == SIGN_IN_REQUEST_CODE) {
            if(resultCode == RESULT_OK) {
                Toast.makeText(this,
                        "Successfully signed in. Welcome!",
                        Toast.LENGTH_LONG)
                        .show();
                displayChatMessages();
            } else {
                Toast.makeText(this,
                        "We couldn't sign you in. Please try again later.",
                        Toast.LENGTH_LONG)
                        .show();

                }

                // Close the app



            }
        }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getItemId() == R.id.menu_sign_out) {
            AuthUI.getInstance().signOut(this)
                    .addOnCompleteListener(new OnCompleteListener<Void>() {
                        @Override
                        public void onComplete(@NonNull Task<Void> task) {
                            Toast.makeText(MainActivity.this,
                                    "You have been signed out.",
                                    Toast.LENGTH_LONG)
                                    .show();

                            // Close activity
                        }
                    });
        }
        return true;

    }


    }

ChatMessage.java

public class ChatMessage {

    private String messageText;
    private String messageUser;
    private long messageTime;

    public ChatMessage(String messageText, String messageUser) {
        this.messageText = messageText;
        this.messageUser = messageUser;

        // Initialize to current time
        messageTime = new Date().getTime();
    }

    public ChatMessage() {

    }

    public String getMessageText() {
        return messageText;
    }

    public void setMessageText(String messageText) {
        this.messageText = messageText;
    }

    public String getMessageUser() {
        return messageUser;
    }

    public void setMessageUser(String messageUser) {
        this.messageUser = messageUser;
    }

    public long getMessageTime() {
        return messageTime;
    }

    public void setMessageTime(long messageTime) {
        this.messageTime = messageTime;
    }

}

Activity_Main.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: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.myapplication.MainActivity">

        <android.support.design.widget.FloatingActionButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:clickable="true"
            android:src="@drawable/ic_send_black_24dp"
            android:id="@+id/fab"
            android:tint="@android:color/white"
            android:layout_alignParentBottom="true"
            android:layout_alignParentEnd="true"
            app:fabSize="mini"
            android:focusable="true" />

        <android.support.design.widget.TextInputLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_toStartOf="@id/fab"
            android:layout_alignParentBottom="true"
            android:layout_alignParentStart="true">

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Input"
                android:id="@+id/input"
                tools:ignore="HardcodedText" />
        </android.support.design.widget.TextInputLayout>

        <ListView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_alignParentTop="true"
            android:layout_alignParentStart="true"
            android:layout_above="@id/fab"
            android:dividerHeight="16dp"
            android:divider="@android:color/transparent"
            android:id="@+id/list_of_messages"
            android:layout_marginBottom="16dp"/>
    </RelativeLayout>

Вот ошибки

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 7892
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: android.view.InflateException: Binary XML file line #14: Binary XML file line #14: Error inflating class android.support.design.widget.FloatingActionButton
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
     Caused by: android.view.InflateException: Binary XML file line #14: Binary XML file line #14: Error inflating class android.support.design.widget.FloatingActionButton
     Caused by: android.view.InflateException: Binary XML file line #14: Error inflating class android.support.design.widget.FloatingActionButton
     Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.design.widget.FloatingActionButton" on path: DexPathList[[zip file "/data/app/com.example.myapplication-1/base.apk"],nativeLibraryDirectories=[/data/app/com.example.myapplication-1/lib/x86, /system/lib, /vendor/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at android.view.LayoutInflater.createView(LayoutInflater.java:609)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:787)
        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 android.view.LayoutInflater.inflate(LayoutInflater.java:377)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:469)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
        at com.example.myapplication.MainActivity.onCreate(MainActivity.java:54)
        at android.app.Activity.performCreate(Activity.java:6662)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

Подскажите что делать, я уже не знаю на что это списывать.