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

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

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

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

You're very welcome Michael :)