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My app won't load when I bring in a MediaPlayer

I'm working on a simple number guessing game. At the moment I have it set that when you guess the correct number it takes you to WinActivity.java. All I want it to do on that screen is say "You won" and to play a little trumpet victory sound (and also display a button that'll bring them to the GameActivity if they want to play again).
The trouble is, when I try bringing in a MediaPlayer the app doesn't even start.
Here is my code for my WinActivity that contains the MediaPlayer.
package com.example.jeremy.numberguessinggame;
import android.content.Intent;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class WinActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_win);
MediaPlayer trumpetsound = MediaPlayer.create(this,R.raw.trumpet);
trumpetsound.start();
Button btnPlayAgain = (Button) findViewById(R.id.button2);
TextView youWon = (TextView) findViewById(R.id.textViewYouWon);
btnPlayAgain.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent playAgainIntent = new Intent(WinActivity.this,GameActivity.class);
startActivity(playAgainIntent);
}
});
}
}
When I run the app the Messages Gradle Build window will pop up and says "error: cannot find symbol variable raw".
I added the raw folder to the res location, and was able to drag the sounds into the folder no problem.
I just don't see why I can't make this MediaPlayer work.
I would love some help. If you need more information I'll be glad to give it to you.

Object specify error

I am trying to code an action bar for my android app and i defined my object to set the logo of the action bar to the default andorid icon before i update. When i run just that code, i get an error on the marked line.
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
public class myabDemo extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_myab_demo);
android.support.v7.app.ActionBar actionBar = getSupportActionBar();
actionBar.setLogo(R.drawable.ic_launcher); // ***Error appears here***
actionBar.setDisplayUseLogoEnabled(true);
actionBar.setDisplayShowHomeEnabled(true);
}
}

It's not R.drawable.icon_launcher but R.drawable.ic_launcher (At least i'm pretty sure you followed the tutorial that puts ic_launcher and not icon_launcher)

I guess you received a nullpointer exception, since actionBar is null.
Add the code below:
requestWindowFeature(Window.FEATURE_NO_TITLE);

Android Studio: Session 'MainActivity': error, but there is no error

Hi I have been racking my brain for hours, did research online but nobody seems to have an answer. My emulator was running my code no problem then I ran it again and I get "Session 'MainActivity': error". I looked through this main activity about 10 times but there is no error sign anywhere and it looks like it should be working fine, I mean it was working before no problem. So I'm not sure if there really is a problem I don't see that Android Studio is not pointing out properly or if this is a different problem all together.
Any help would be greatly appreciated. Thank you.
package tekvision.codedecrypter;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.Toast;
import gameInfo.GameDatabase;
public class MainActivity extends ActionBarActivity {
//Runs before the application is created
private Button mCampaignButton;
private final Context context = this;
//When the application is created
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Instantiate a GameDatabase object (this activity)
final GameDatabase gDB = new GameDatabase(context);
gDB.fillGameDatabase();
//Keeps screen on so it doesn't fall asleep
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
//Finding button by button id after application is created
mCampaignButton = (Button)findViewById(R.id.campaignButtonID);
//Checks if the campaign button is clicked
mCampaignButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String ans = gDB.getAnswer("Ancient",1);
//Toast pop up message
Toast toast = Toast.makeText(getApplicationContext(),
ans ,
Toast.LENGTH_SHORT);
toast.show();
//Intent to go from main activity to campaign Level Select Activity
final Intent intent = new Intent(MainActivity.this, CampaignSelectLevel.class);
startActivity(intent);
}
});
}
}

Try rebuilding and cleaning your project.
Build > Rebuild Project
and
Build > Clean Project

Android Studio ERROR: Cannot resolve symbol 'View'

I'm trying to follow this tutorial from Google to create your own android app with Android Studio. But when I follow the 4th step on this page: http://developer.android.com/training/basics/firstapp/starting-activity.html Android Studio ends up with this error:
Cannot resolve symbol 'View'
This is what my code looks like at the moment:
public class MainActivity extends ActionBarActivity {
/** Called when the user clicks the Send button */
public void sendMessage(View view) { <--- (This line ends up with the error)
// Do something in response to button
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#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;
}
#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);
}
}
What's wrong with this code? I'm not experienced in java and after looking at other questions I still couldn't find the right solution.
Thanks for helping!

I think you forget to include the import statement for View. Add the following import in your code
import android.view.View;

I am doing the same tutorial and ran into the same problem (that's why I found this question).
I see they explain this issue in the next paragraph named "Build an Intent":
Android Studio will display Cannot resolve symbol errors because this
code references classes that are not imported. You can solve some of
these with Android Studio's "import class" functionality by pressing
Alt + Enter (or Option + Return on Mac). Your imports should end up as
the following:
import android.content.Intent; import
android.support.v7.app.AppCompatActivity; import android.os.Bundle;
import android.view.View; import android.widget.EditText;
https://developer.android.com/training/basics/firstapp/starting-activity.html#BuildIntent

This problem can be resolved easily either by pressing alt + enter on the error to import android.view.View or by cross-checking that your method is outside protected void onCreate(Bundle savedInstanceState) and in the class parenthesis.

How to put Interfaces in a library for android App

to the point, i am working in a library for android app's, all programing part is almost finish, i am testing a idea.
the idea is put some interfaces in the librery that i am working, and this GUI can be loaded in the main app.
i try to do it but i get to error the first was i did not declare the activity in the AndroidManifest in the main app, the second one is the one a i cant solve, the autogenerated Class R don't capture the GUI that it is in the librery.
it is anyway i can do this or it is imposible.
code to see what i am trying todo
in my librery (movilsecure)
EmisionActivity.java (have the activity_emision.xml in the res of my librery)
in the Main Android App (
import ve.com.idyseg.movilsecure.EmisionActivity;
import ve.com.idyseg.movilsecure.MSMasterControllerTEST;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void captureEvent (View v){
Intent intento = new Intent(this,EmisionActivity.class);
startIntent(intento);
}
}

In Eclipses, right click the project, the click Build Path then click Add Library. Please comment if you're still stuck.

In the library's manifest, in the <activity> node, did you set android:exported="true"?
Example:
<activity
android:name="com.example.app.EmisionActivity"
android:exported="true">
</activity>