startActivity crashes when trying to respond to menu click.

Question

I know this has been covered elsewhere, but I'm new to the Android platform and am having a hard time figuring out how to add basic menu options to my first app.

I have an options menu setup using

@Override
public boolean onCreateOptionsMenu(Menu menu){
  MenuInflater inflater = getMenuInflater();
  inflater.inflate(R.menu.menu, menu);
  return true;
}

and

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
<item android:id="@+id/menuPrefs" android:icon="@android:drawable/ic_menu_preferences" android:title="Settings"></item>
</menu>

Then within my main java class I have

@Override
public boolean onOptionsItemSelected(MenuItem item){

 if(item.getItemId()==R.id.menuPrefs) {
  showPrefs();
 }
private void showPrefs() {
 Intent i = new Intent(this, Prefs.class);
 startActivity(i);
}

And then in Prefs.java I have

public class Prefs extends Activity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
      Toast.makeText(getBaseContext(), "FNORD", Toast.LENGTH_LONG).show();
     }
    }

Now from this I would expect to see the Toast message "FNORD" when the menu option is pressed, however the application stops unexpectedly.

If I move the toast statement into the showPrefs() function in place of the startActivity call it works.

Answer 1

You need to learn how to Debug in Eclipse and how to use the ADB and DDMS tools.

In order to get more details about an exception/force close you need to look for a view in Eclipse called Logcat(you will find in the DDMS perspective) there you will find a detailed traceback when/what and on what line is the issue.

For this you should read a complete article about Debugging in Android using Eclipse

Answer 2

You forgot to call super.onCreate(Bundle savedInstanceState); on Prefs' onCreate() method.

Answer 3

Solution was that I needed to add the Prefs.xml to the manifest.