title: Android Studio: App crashing after Splash screen
body: <p>my app is crashing after a splash screen i tried to implement.
  I don't know where the problem occurs.</p>
  
  <p>I tried to fix this like 2 hours and even researched the web but somehow i don't get it to work.
  Maybe you guys can look over the code and give me some hints? I would appreciate that.</p>
  
  <p>AndroidManifest.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"
      package="com.example.noctis"&gt;
  
      &lt;application tools:ignore="GoogleAppIndexingWarning"
          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"&gt;
  
          &lt;activity
              android:name=".impressum"
              android:label="@string/title_activity_impressum"
              android:theme="@style/AppTheme.NoActionBar" /&gt;
          &lt;activity
              android:name=".MainActivity"
              android:label="@string/app_name"
              android:theme="@style/AppTheme.Launcher"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
      &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p>launch_screen.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  &lt;layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:opacity="opaque"&gt;
  
      &lt;item android:drawable="@color/colorContentBackground"/&gt;
  
      &lt;item&gt;
          &lt;bitmap
              android:src="@drawable/rsz_l52878klein"
              android:gravity="center"/&gt;
      &lt;/item&gt;
  
  &lt;/layer-list&gt;
  </code></pre>
  
  <p>activity_main.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout
      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:layout_width="match_parent"
      android:layout_height="match_parent"
      android:background="@color/colorContentBackground"
      tools:context=".MainActivity"&gt;
  
  
  
      &lt;android.support.design.widget.AppBarLayout
          android:layout_height="wrap_content"
          android:layout_width="match_parent"
          android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="@color/colorPrimary"
              app:popupTheme="@style/AppTheme.PopupOverlay"
              android:layout_gravity="center_horizontal"&gt;
  
              &lt;ImageView
                  android:layout_width="110dp"
                  android:layout_height="wrap_content"
                  android:layout_gravity="center"
                  android:src="@drawable/rsz_l52878"/&gt;
  
          &lt;/android.support.v7.widget.Toolbar&gt;
  
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;include layout="@layout/content_main"/&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/fab"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="bottom|end"
          android:layout_margin="16dp"
          app:backgroundTint="@color/actionButton"
          app:fabSize="normal"
          android:src="@drawable/ic_add_black_32dp" /&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>styles.xml</p>
  
  <pre><code>&lt;resources&gt;
  
      &lt;style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"&gt;
          &lt;item name="colorPrimary"&gt;@color/colorPrimary&lt;/item&gt;
          &lt;item name="colorPrimaryDark"&gt;@color/colorPrimaryDark&lt;/item&gt;
          &lt;item name="colorAccent"&gt;@color/colorAccent&lt;/item&gt;
      &lt;/style&gt;
  
      &lt;style name="AppTheme.Launcher" parent="AppTheme"&gt;
          &lt;item name="android:windowBackground"&gt;@drawable/launch_screen&lt;/item&gt;
      &lt;/style&gt;
  
  
      &lt;style name="AppTheme.NoActionBar"&gt;
          &lt;item name="windowActionBar"&gt;false&lt;/item&gt;
          &lt;item name="windowNoTitle"&gt;true&lt;/item&gt;
      &lt;/style&gt;
  
      &lt;style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" /&gt;
  
      &lt;style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" /&gt;
  &lt;/resources&gt;
  </code></pre>
  
  <p>MainActivity.java</p>
  
  <pre><code>@Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          Toolbar toolbar = findViewById(R.id.toolbar);
          toolbar.setTitle("");
          setSupportActionBar(toolbar);
  
  
          FloatingActionButton fab = findViewById(R.id.fab);
          fab.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
  
              }
          });
      }
  
      @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_main, menu);
          return true;
      }
  </code></pre>
  
  <p>So..the actual splash screen is displayed, but after that the app just crashes. I dont get why :/</p>
  
  <p>Edit: (crashlog)</p>
  
  <pre><code>2019-03-25 21:06:18.588 14651-14651/com.example.noctis E/AndroidRuntime: FATAL EXCEPTION: main
      Process: com.example.noctis, PID: 14651
      java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.noctis/com.example.noctis.MainActivity}: 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:3107)
          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3250)
          at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
          at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
          at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1947)
          at android.os.Handler.dispatchMessage(Handler.java:106)
          at android.os.Looper.loop(Looper.java:214)
          at android.app.ActivityThread.main(ActivityThread.java:7032)
          at java.lang.reflect.Method.invoke(Native Method)
          at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964)
       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.AppCompatDelegateImpl.setSupportActionBar(AppCompatDelegateImpl.java:345)
          at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:130)
          at com.example.noctis.MainActivity.onCreate(MainActivity.java:21)
          at android.app.Activity.performCreate(Activity.java:7327)
          at android.app.Activity.performCreate(Activity.java:7318)
          at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
          at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3087)
          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3250) 
          at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
          at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
          at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1947) 
          at android.os.Handler.dispatchMessage(Handler.java:106) 
          at android.os.Looper.loop(Looper.java:214) 
          at android.app.ActivityThread.main(ActivityThread.java:7032) 
          at java.lang.reflect.Method.invoke(Native Method) 
          at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964) 
  2019-03-25 21:06:18.599 14651-14651/com.example.noctis I/Process: Sending signal. PID: 14651 SIG: 9
  </code></pre>