Error starting the java.lang.RuntimeException App:

This problem arises when I start the app. This is returned to me by Google Play because testing it in my emulator and cell phone does not cause problems.

java.lang.RuntimeException: 
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2198)
  at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2257)
  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:5086)
  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:785)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:601)
  at dalvik.system.NativeStart.main (Native Method)
Caused by: android.view.InflateException: 
  at android.view.LayoutInflater.createView (LayoutInflater.java:620)
  at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView (PhoneLayoutInflater.java:56)
  at android.view.LayoutInflater.onCreateView (LayoutInflater.java:669)
  at android.view.LayoutInflater.createViewFromTag (LayoutInflater.java:694)
  at android.view.LayoutInflater.inflate (LayoutInflater.java:469)
  at android.view.LayoutInflater.inflate (LayoutInflater.java:397)
  at android.view.LayoutInflater.inflate (LayoutInflater.java:353)
  at android.support.v7.app.AppCompatDelegateImplV9.setContentView (AppCompatDelegateImplV9.java:289)
  at android.support.v7.app.AppCompatActivity.setContentView (AppCompatActivity.java:139)
  at com.yamil.sirenadepolicia.MainActivity.onCreate (MainActivity.java:27)
  at android.app.Activity.performCreate (Activity.java:5248)
  at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1110)
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2162)

Tonight I put the activitymain and manifest

XML Activity Main

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:ads="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:gravity="center"
    android:background="@drawable/fondodos"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:gravity="center"
        android:orientation="vertical"
        android:padding="10dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="20dp"
            android:textSize="40sp"
            android:textColor="@android:color/background_light"
            android:text="@string/inicio" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="@android:color/background_light"
            android:text="@string/iniciodos" />

    </LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/boton_policia"
        android:padding="20dp"
        android:text="@string/policia"
        android:gravity="center"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/boton_sirenas"
        android:padding="20dp"
        android:text="@string/sirenas"
        android:gravity="center"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/pistola"
        android:padding="20dp"
        android:text="@string/pistola"
        android:gravity="center"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp">

        <com.google.android.gms.ads.AdView
            android:id="@+id/adView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            ads:adSize="BANNER"
            ads:adUnitId="ca-app-pub-3104204509358318/2502427265" />
    </LinearLayout>


</LinearLayout>

Activity Main

package com.yamil.sirenadepolicia;



import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.ads.InterstitialAd;


public class MainActivity extends AppCompatActivity {

    public Button policia,sirenas,pistola; //Creacion de botones
    private InterstitialAd mInterstitialAd;


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

        //FullScreen
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//FullScreen


        //PUBLICIDAD
        mInterstitialAd = new InterstitialAd(this);
        mInterstitialAd.setAdUnitId("ca-app-pub-3104204509358318/9522706159");
        mInterstitialAd.loadAd(new AdRequest.Builder().build());
        mInterstitialAd.setAdListener(new AdListener() {
            @Override
            public void onAdClosed() {
                // Load the next interstitial.
                mInterstitialAd.loadAd(new AdRequest.Builder().build());
            }
        });

        AdView mAdView = (AdView) findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);
        //PUBLICIDAD

        //REFERENCIAS
        policia = (Button) findViewById(R.id.boton_policia);
        sirenas = (Button) findViewById(R.id.boton_sirenas);
        pistola =(Button)findViewById(R.id.pistola);
        //FIN REFERENCIAS


        //BOTONES
        policia.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent a = new Intent(MainActivity.this, policia.class);
                startActivity(a);
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });

        sirenas.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent b = new Intent(MainActivity.this, sirenas.class);
                startActivity(b);
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });

        pistola.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent c=new Intent(MainActivity.this,pistola.class);
                startActivity(c);
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
        //FIN DE BOTONES

    }

}

Build

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId 'com.yamil.sirenadepolicia'
        minSdkVersion 19
        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'
        }
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.google.android.gms:play-services:11.0.4'
    testCompile 'junit:junit:4.12'
}

Try to look for some error in the xml file and I have not found anything. I would appreciate the help.

This is another one of the errors

java.lang.RuntimeException: 
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2198)
  at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2257)
  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:5086)
  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:785)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:601)
  at dalvik.system.NativeStart.main (Native Method)
Caused by: java.lang.NullPointerException: 
  at com.yamil.sirenadepolicia.MainActivity.onCreate (MainActivity.java:47)
  at android.app.Activity.performCreate (Activity.java:5248)
  at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1110)
  at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2162)