Androidスタジオ：E/AndroidRuntime：致命的な例外：メイン

Question

私のアプリケーションを実行するたびに、それは停止します。そして、これは私のエラーです：

package com.example.pcuser.iwoods; 

import android.content.Intent; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.widget.TextView; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.view.View; 
import android.support.design.widget.NavigationView; 
import android.support.v4.view.GravityCompat; 
import android.support.v4.widget.DrawerLayout; 
import android.support.v7.app.ActionBarDrawerToggle; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 


public class UserProfile extends AppCompatActivity 
     implements NavigationView.OnNavigationItemSelectedListener { 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setContentView(R.layout.activity_user_profile); 

     setSupportActionBar(toolbar); 

     FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 

     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
      this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); 
     drawer.setDrawerListener(toggle); 
     toggle.syncState(); 

     NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); 
     navigationView.setNavigationItemSelectedListener(this); 
     Intent intent = getIntent(); 
     String username = intent.getStringExtra(MainActivity.username); 

     TextView textView = (TextView) findViewById(R.id.textView2); 

     textView.setText("Welcome "+username); 
    } 

    @Override 
    public void onBackPressed() { 
     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     if (drawer.isDrawerOpen(GravityCompat.START)) { 
      drawer.closeDrawer(GravityCompat.START); 
     } else { 
      super.onBackPressed(); 
     } 
    } 
    @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_user_profile, 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); 
    } 
    @SuppressWarnings("StatementWithEmptyBody") 
    @Override 
    public boolean onNavigationItemSelected(MenuItem item) { 
     // Handle navigation view item clicks here. 
     int id = item.getItemId(); 

     if (id == R.id.nav_camera) { 
      // Handle the camera action 
     } else if (id == R.id.nav_gallery) { 

     } else if (id == R.id.nav_slideshow) { 

     } else if (id == R.id.nav_manage) { 

     } else if (id == R.id.nav_share) { 

     } else if (id == R.id.nav_send) { 

     } 

     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     drawer.closeDrawer(GravityCompat.START); 
     return true; 
    } 
} 

Androidのマニフェスト：ここに私のjavaファイルです

08-28 09:36:38.649 17259-17259/com.example.pcuser.iwoods E/AndroidRuntime: FATAL EXCEPTION: main 
    Process: com.example.pcuser.iwoods, PID: 17259 
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.pcuser.iwoods/com.example.pcuser.iwoods.UserProfile}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233) 
    at android.app.ActivityThread.access$800(ActivityThread.java:135) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:136) 
    at android.app.ActivityThread.main(ActivityThread.java:5001) 
    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.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. 
    at android.support.v7.app.AppCompatDelegateImplV7.setSupportActionBar(AppCompatDelegateImplV7.java:198) 
    at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:130) 
    at com.example.pcuser.iwoods.UserProfile.onCreate(UserProfile.java:28) 
    at android.app.Activity.performCreate(Activity.java:5231) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)  
    at android.app.ActivityThread.access$800(ActivityThread.java:135)  
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)  
    at android.os.Handler.dispatchMessage(Handler.java:102)  
    at android.os.Looper.loop(Looper.java:136)  
    at android.app.ActivityThread.main(ActivityThread.java:5001)  
    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)  

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

<uses-permission android:name="android.permission.INTERNET" /> 

<application 
    android:allowBackup="true" 
    android:icon="@mipmap/ic_launcher" 
    android:label="@string/app_name" 
    android:supportsRtl="true" 
    android:theme="@style/AppTheme"> 
    <activity 
     android:name=".SplashScreen" 
     android:label="@string/app_name" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 
      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
    <activity android:name=".MainActivity"> 
    </activity> 
    <activity android:name=".UserProfile"> 
    </activity> 

</application> 

は私がサポートを削除し、それを戻すためにしてみてください。しかし、何も起こりません。それはいつも止まる。このJavaコードはナビゲーションテーブル用で、ログインする前のページ（mysqlサーバと000webhostを使用してオンライン）です。マニフェストでのアクティビティタグにこの行を追加すること

Answer 1

試してみてください。このような

android:theme="@style/AppTheme.NoActionBar"> 

：

<activity android:name=".UserProfile" 
android:theme="@style/AppTheme.NoActionBar"/> 

AppTheme.NoActionBar：

<style name="AppTheme.NoActionBar"> 
    <item name="windowActionBar">false</item> 
    <item name="windowNoTitle">true</item> 
</style>