RecyclerView and Toolbar not found

Question

I'm having problems with a recyclerView. This is the definition in the xml :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v7.widget.Toolbar
        android:id="@+id/tlbMenuDetalle"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:elevation="4dp"
        />


    <android.support.v7.widget.RecyclerView
        android:id="@+id/rcyViatgesDetall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
</LinearLayout>

I try to use it in the following class:

public class ViatgeDetall extends AppCompatActivity {
    private RecyclerView mRcyViatgesDetall;
    private AdapterViatgesDetall mAdapterViatgesDetall;
    private ViatgesManager.Viatge mViatge;

    private ArrayList<ViatgesManager.Viatge> viatges;

    protected void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

      Toolbar myToolbar = (Toolbar) findViewById(R.id.tlbMenuDetalle);
       setSupportActionBar(myToolbar);
      getSupportActionBar().setTitle("TravelApp");
       getSupportActionBar().setHomeButtonEnabled(true);
       getSupportActionBar().setDisplayHomeAsUpEnabled(true);


        Log.d("myTag", "Detalle OnCreate" );
        mRcyViatgesDetall = (RecyclerView) findViewById(R.id.rcyViatgesDetall);


        Bundle extras = getIntent().getExtras();
        if(extras != null)
        {
            viatges  = ViatgesManager.ITEMS;
            int f = getIntent().getIntExtra("viatge",0);
            mViatge = viatges.get(f-1);
            Log.d("myTag", "Detalle OnCreate" + mViatge.getName());
        }
        ArrayList<ViatgesManager.Stop> stops =  mViatge.getStops();


        LinearLayoutManager llm = new LinearLayoutManager(this);
        llm.setOrientation(LinearLayoutManager.VERTICAL);
        GridLayoutManager glm = new GridLayoutManager(this,2);
        glm.setOrientation(GridLayoutManager.HORIZONTAL);
        mRcyViatgesDetall.setLayoutManager(llm);

        mAdapterViatgesDetall = new AdapterViatgesDetall(stops, this);
        mRcyViatgesDetall.setAdapter(mAdapterViatgesDetall);



    }
}

I don't see what i'm doing worng, beacuse i keep getting this error :

FATAL EXCEPTION: main Process: com.example.usuari.myapplication3, PID: 26507 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.usuari.myapplication3/com.example.usuari.myapplication3.ViatgeDetall}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setTitle(java.lang.CharSequence)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3254) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3350) at android.app.ActivityThread.access$1100(ActivityThread.java:222) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1795) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:158) at android.app.ActivityThread.main(ActivityThread.java:7229) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setTitle(java.lang.CharSequence)' on a null object reference at com.example.usuari.myapplication3.ViatgeDetall.onCreate(ViatgeDetall.java:37) at android.app.Activity.performCreate(Activity.java:6876) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3207) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3350)  at android.app.ActivityThread.access$1100(ActivityThread.java:222)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1795)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:158)  at android.app.ActivityThread.main(ActivityThread.java:7229)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Even if i comment the part about the toolbar i get a very similar error but with the RecyclerView. I'm working with sdk 25 if that helps...

This is my manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.usuari.myapplication3">

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".EditViatge"
            android:label="EditVIatge"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".ViatgeDetall"
            android:label="ViatgeDetall"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

Answer 1

The error was in :

setContentView(R.layout.activity_main);

That wasn't the correct layout to set.Instead it should had been the layout of the prevoiusly shown xml...

Answer 2

You have to add correct layout file I think you put incorrect layout file name

setContentView(R.layout.activity_main);