活動ComponentInfo（LOGCAT）を開始することができません

私は新しいAndroidプログラマだと最近、私はlogcatでこのエラーを取得しています：活動ComponentInfo（LOGCAT）を開始することができません

03-22 15:33:49.395 13639-13639/com.abaco.awser E/AndroidRuntime: FATAL EXCEPTION: main 
Process: com.abaco.awser, PID: 13639 
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.abaco.awser/com.abaco.awser.MainActivity}: java.lang.NullPointerException 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2429) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493) 
    at android.app.ActivityThread.access$800(ActivityThread.java:166) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:136) 
    at android.app.ActivityThread.main(ActivityThread.java:5584) 
    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:1268) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084) 
    at dalvik.system.NativeStart.main(Native Method) 
    Caused by: java.lang.NullPointerException 
    at com.abaco.awser.MainActivity.onCreate(MainActivity.java:23) 
    at android.app.Activity.performCreate(Activity.java:5447) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2393) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)  
    at android.app.ActivityThread.access$800(ActivityThread.java:166)  
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)  
    at android.os.Handler.dispatchMessage(Handler.java:102)  
    at android.os.Looper.loop(Looper.java:136)  
    at android.app.ActivityThread.main(ActivityThread.java:5584)  
    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:1268)  
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)  
    at dalvik.system.NativeStart.main(Native Method)

ここに私のMainActivity.javaです：

package com.abaco.awser; 

import android.content.pm.ActivityInfo; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.Window; 
import android.view.WindowManager; 
import android.webkit.WebSettings; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 

public class MainActivity extends AppCompatActivity { 

    @Override 
    public void onBackPressed() { 
    } 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     WebView myWebView = (WebView) findViewById(R.id.activity_main_webview); 
     myWebView.setWebViewClient(new WebViewClient()); 
     myWebView.loadUrl("http://primopizza.com.br/eloja"); 

     WebSettings webSettings = myWebView.getSettings(); 
     webSettings.setJavaScriptEnabled(true); 

     setContentView(R.layout.activity_main); 
    } 
}

そして、ここでは私のactivity_main.xmlだ

<?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="match_parent" 
    android:layout_height="match_parent" 
    tools:context="com.abaco.abawser.MainActivity"> 

    <WebView 
     android:id="@+id/activity_main_webview" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"/> 

</RelativeLayout>

あなたは私は、このエラーを解決する助けてくださいことはできますか？私はすでにすべてを試しました。

出典

2016-03-22 Marcos Sartorato