[Java for Android App Development] Koopla:
Hi, I am very new to developing apps and I am following the tutorial from Google's Android Training and I am currently at the "Starting your second Activity" stage. The purpose of the tutorial is to create a second activity so that the "Send" button will display the message that I have written.

There are 2 errors here:

Unknown member 'action_settings' of 'com.mycompany.myapp.R.id'
Unknown member 'fragment_display_message of 'com.mycompany.myapp.R.id'

and this is the code where the error occurs at DisplayMessageActivity java class:

import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.content.*;
import com.mycompany.myapp.*;

public class DisplayMessageActivity extends Activity
{@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);

// Set the text view as the activity layout
setContentView(textView);
}

@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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}

/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {

public PlaceholderFragment() { }

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_display_message,
container, false);
return rootView;
}
}
}

I can't seem to fix this error. I have been trying to find the solution but to no avail.

I don't kow if it help you guys but here's the R.java:

/* AUTO-GENERATED FILE. DO NOT MODIFY.
*
* This class was automatically generated by the
* aapt tool from the resource data it found. It
* should not be modified by hand.
*/

package com.mycompany.myapp;

public final class R {
public static final class attr {
}
public static final class drawable {
public static final int ic_launcher=0x7f020000;
}
public static final class id {
public static final int edit_message=0x7f050000;
}
public static final class layout {
public static final int main=0x7f030000;
}
public static final class string {
public static final int action_settings=0x7f040003;
public static final int app_name=0x7f040000;
public static final int button_send=0x7f040002;
public static final int edit_message=0x7f040001;
public static final int title_activity_display_message=0x7f040005;
public static final int title_activity_main=0x7f040004;
}
}

Here's the R java:

/* AUTO-GENERATED FILE. DO NOT MODIFY.
*
* This class was automatically generated by the
* aapt tool from the resource data it found. It
* should not be modified by hand.
*/

package com.mycompany.myapp;

public final class R {
public static final class attr {
}
public static final class drawable {
public static final int ic_launcher=0x7f020000;
}
public static final class id {
public static final int edit_message=0x7f050000;
}
public static final class layout {
public static final int main=0x7f030000;
}
public static final class string {
public static final int action_settings=0x7f040003;
public static final int app_name=0x7f040000;
public static final int button_send=0x7f040002;
public static final int edit_message=0x7f040001;
public static final int title_activity_display_message=0x7f040005;
public static final int title_activity_main=0x7f040004;
}
}

Here's the strings xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>

<string name="app_name">My App</string>
<string name="edit_message">Enter a message</string>
<string name="button_send">Send</string>
<string name="action_settings">Settings</string>
<string name="title_activity_main">MainActivity</string>
<string name="title_activity_display_message">My Message</string>
</resources>

Here's the Mainactivity java

import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.content.*;
import com.mycompany.myapp.*;

public class MainActivity extends Activity
{
public final static String EXTRA_MESSAGE = "com.example.myapp.MESSAGE";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);}
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}

}