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Android Android Activity Lifecycle Introducing SharedPreferences Saving and Retrieving Data with SharedPreferences

Posted by Malcolm Mutambanengwe
Malcolm Mutambanengwe
4,205 Points

shared preferences

Hi Steve Hunter. Am now on the android activity lifecycle. Still much more to learn.

MainActivity.java 
import android.view.View;
import android.os.Bundle;

public class MainActivity extends Activity {
  public static final String PREFS_FILE;
  public static final String KEY_CHECKBOX;
  public SharedPreferences mSharedPreferences;
  public SharedPreferences.Editor mEditor;
  public CheckBox mCheckBox;
  public EditText mEditText;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mSharedPreferences = getSharedPreferences(PREFS_FILE, Context.MODE_PRIVATE);
    mEditText = mSharedPreferences.edit();

  }
}
Steve Hunter
Steve Hunter
57,712 Points

OK - ask a question and then help me out. What did you expect your code to do; what did it do; what error did you get; why do you think that happened?

I'm not going to just chuck you a solution every time! :wink:

Steve.

Malcolm Mutambanengwe
Malcolm Mutambanengwe
4,205 Points

Kikiki. Yep. In the video PREFS_FILE and KEY_CHECKBOX both have values but not in the code given in the problem.

public static final String PREFS_FILE = preferences; public static final String KEY_CHECKBOX = key_edittext;

I tried assigning them values but that didn't work. Let me get the errors which I got.

Then initialize both of these fields in the onCreate method. 

mSharedPreferences = getSharedPreferences(PREFS_FILE, Context.MODE_PRIVATE);
mEditText = mSharedPreferences.edit()

4 Answers

Steve Hunter
Steve Hunter
57,712 Points

Try:

private static final String PREFS_FILE = "prefs";
private static final String KEY_CHECKBOX = "key_checkbox";
Steve Hunter
Steve Hunter
57,712 Points
Steve Hunter
Steve Hunter
57,712 Points

Actually, no. I've not done this course nor do I have any experience in database actions within Android; I don't know the solution.

Malcolm Mutambanengwe
Malcolm Mutambanengwe
4,205 Points

I'll wrestle with this one. Must have an answer by tomorrow afternoon.

Steve Hunter
Steve Hunter
57,712 Points

Is this a college course, or something? If I get a minute, I'll work through the video, if that'll help. Tomorrow's quite busy but I'll see if I can manage 20 minutes. And what time zone are you in? It's 21:30 here now.

Steve Hunter
Steve Hunter
57,712 Points
Steve Hunter
Steve Hunter
57,712 Points

Yes. When you assign a string to a variable, or constant, you need to treat it as a string, enclosing it with double quotes. So, 

public String myName = "Steve Hunter";
public static final String MY_NAME = "Steve Hunter";

Yeah?

Steve.

Malcolm Mutambanengwe
Malcolm Mutambanengwe
4,205 Points
Malcolm Mutambanengwe
Malcolm Mutambanengwe
4,205 Points

Ok. So I can use quotes"" outside brackets as well. So in effect if a CONSTANT is a String I have to use quotes to assign it a value?