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Android Build a Blog Reader Android App Rebuilding from Scratch Adding Data for the List

Posted by Michael McDonald
Michael McDonald
2,877 Points

Why can I not declare my ArrayAdapter as private?

The error I get is "Illegal start of expression". If I remove the 'private' keyword, then my code passes the test.

com/example/MainListActivity.java 
package com.example;

import android.app.ListActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;

public class MainListActivity extends ListActivity {
  public String mSongTitles[] = {"Wah","tjg","kfg"};
    @Override
    public void onCreate(Bundle savedInstanceState) {
      private ArrayAdapter <String> adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1,mSongTitles);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_list);
    }
}
Ragnar Sinikas
Ragnar Sinikas
11,573 Points
Ragnar Sinikas
Ragnar Sinikas
11,573 Points

This ArrayAdapter is in the method, you can declare it as member variable as a private field....

Michael McDonald
Michael McDonald
2,877 Points

What is the difference and how do I make the distinction?

Ragnar Sinikas
Ragnar Sinikas
11,573 Points
Ragnar Sinikas
Ragnar Sinikas
11,573 Points

Any variable set up inside of a method can't be accessed outside of that method. It's known as a local variable - it's local to the method. But when you declare it outside of the method as public String mSongTitles[] = {"Wah","tjg","kfg"}; then you can make it public, private or protected

Michael McDonald
Michael McDonald
2,877 Points

Thank you very much. That's just the reminder I needed.

1 Answer

Joseph Greene
PLUS
Joseph Greene
Courses Plus Student 7,638 Points
Joseph Greene
Joseph Greene
Courses Plus Student 7,638 Points

It's all about scope. If you want a variable of any kind to be seen outside it's parent method then it can't be private. This is a good thing. You should always strive for a degree of seperation. To make private variables talk you would use what's called getters and setters. But I think that's out of the scope of the lesson. Once you've got some more android under your belt I recommend taking a full fledged Java course or getting a good book or two. It will make you a better android developer. Keep up the awesome work. You're asking the right kinds of questions to becoming a good programmer.