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

michael lee
michael lee
5,179 Points
Posted by michael lee
michael lee
5,179 Points

how to set the string value to the check?

in my code I am trying to convert String into check value in order to retrieve, but can't find a way to do that

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

public class MainActivity extends Activity {

  public CheckBox mCheckBox;
   static final String PREFS_FILE = "com.teamtreehouse.sharedpreferencesapp.preferences";
   static final String KEY_CHECKBOX = "KEY_CHECKBOX";
  private SharedPreferences mSharedPreferences;
    private SharedPreferences.Editor mEditor;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mCheckBox = (CheckBox) findViewById(R.id.checkBox);
    mSharedPreferences = getSharedPreferences(PREFS_FILE, Context.MODE_PRIVATE);
        mEditor = mSharedPreferences.edit();

    CheckBox editTextCheck= mSharedPreferences.getString(KEY_CHECKBOX, "");
        mCheckBox.setChecked(editTextCheck);
  }

    @Override
  protected void onPause() {
        super.onPause();

        mEditor.putBoolean(KEY_CHECKBOX, mCheckBox.isChecked());
        mEditor.apply();
    }
}

1 Answer

Lauren Moineau
Lauren Moineau
9,483 Points

Hi Michael. Let's have a look at your code retrieving the stored value:

CheckBox editTextCheck= mSharedPreferences.getString(KEY_CHECKBOX, "");

As with a Bundle, remember that whatever you're putting in, you're getting out. It won't change type in between. In onPause(), you saved a Boolean in SharedPreferences, using putBoolean(). So here, you need to get a Boolean, not a String.

Now, because it's a Boolean, you'll have to save it in a new Boolean variable, just like Ben created a String variable to store that retrieved String value in the video.

Finally, because it's a Boolean and not a String, you can't give an empty String as the default value (""). The instructions say : "If there isn't a saved value, the CheckBox should NOT be checked."

Hint: Remember that a Boolean can only have 2 values: true or false. So which should we put as default here so that the checkbox is not checked?

Hope that helps you complete the challenge :)

michael lee
michael lee
5,179 Points
michael lee
michael lee
5,179 Points

thanks a lot, Lauren. It is truly very helpful, I appreciate the detailed explanation~

Lauren Moineau
Lauren Moineau
9,483 Points

You're very welcome Michael :)