error loading APK on device

This having the following error when I install the apk on my device the log throws this error:

Logcat error

09-11 11:59:11.218 16688-16688/com.example.g_talent.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.g_talent.myapplication, PID: 16688
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.g_talent.myapplication/com.example.g_talent.myapplication.MainActivity}: java.lang.NullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
    at android.app.ActivityThread.access$800(ActivityThread.java:139)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5102)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
    at com.example.g_talent.myapplication.MainActivity.onCreate(MainActivity.java:37)
    at android.app.Activity.performCreate(Activity.java:5248)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2173)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269) 
    at android.app.ActivityThread.access$800(ActivityThread.java:139) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:136) 
    at android.app.ActivityThread.main(ActivityThread.java:5102) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:515) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
    at dalvik.system.NativeStart.main(Native Method) 

Code:

package com.example.g_talent.myapplication;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.nio.charset.CharacterCodingException;
import java.util.ArrayList;
import java.util.Set;

public class MainActivity extends AppCompatActivity {

    CheckBox enable_bt, visible_bt;
    TextView name_bt;
    ImageView search_bt;
    ListView list_view;

    private BluetoothAdapter BA;
    private Set<BluetoothDevice> pairedDevice;

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

        enable_bt.findViewById(R.id.enable_bt);
        visible_bt.findViewById(R.id.visible_bt);
        name_bt.findViewById(R.id.name_bt);
        search_bt.findViewById(R.id.search_bt);
        list_view.findViewById(R.id.list_view);

        name_bt.setText(getLocalBluetoothName());
        BA = BluetoothAdapter.getDefaultAdapter();



        if(BA == null) {
            Toast.makeText(MainActivity.this,"No soportado",Toast.LENGTH_SHORT).show();
            finish();

        }
        if (BA.isEnabled()){
            enable_bt.setChecked(true);
        }
        enable_bt.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {


                if(!isChecked){
                    BA.disable();
                    Toast.makeText(MainActivity.this,"Apagado",Toast.LENGTH_SHORT).show();
                }else{
                    Intent intentoOn = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
                    startActivityForResult(intentoOn,0);
                    Toast.makeText(MainActivity.this,"Activado",Toast.LENGTH_SHORT).show();
                }


            }
        });

        visible_bt.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(!isChecked){
                    Intent getVisible = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
                    startActivityForResult(getVisible,0);
                    Toast.makeText(MainActivity.this,"Activo por un momento",Toast.LENGTH_SHORT).show();
                }
            }
        });

        search_bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            list();
            }
        });
    }


    private void list() {
        pairedDevice = BA.getBondedDevices();
        ArrayList listar = new ArrayList();

        for(BluetoothDevice bt : pairedDevice){
            listar.add(bt.getName());

        }
        Toast.makeText(MainActivity.this,"Activo por un momento",Toast.LENGTH_SHORT).show();
        ArrayAdapter adapter;
        adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1, listar);
        list_view.setAdapter(adapter);
    }
    public String getLocalBluetoothName(){
        if (BA == null){
            BA = BluetoothAdapter.getDefaultAdapter();
        }
        String name;
        name = BA.getName();
        if (name == null){
            name = BA.getAddress();

        }
        return name;
    }

}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.g_talent.myapplication">

    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <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">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>