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

Posted by Kenneth Phillips
Kenneth Phillips
Courses Plus Student 10,188 Points

SharedPreferences

It throws this error:

./MainActivity.java:21: error: method getBoolean in class SharedPreferences cannot be applied to given types; mSharedPreferences.getBoolean(KEY_CHECKBOX); ^ required: String,boolean found: String reason: actual and formal argument lists differ in length 1 error

Honestly the whole getBoolean() idea has confused me. I looked up the documentation and some examples but that didn't help much. I'd appreciate any help.

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

public class MainActivity extends Activity {

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

  public CheckBox mCheckBox;

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

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

    mSharedPreferences.getBoolean(KEY_CHECKBOX);
    mCheckBox.setChecked(true);

    mCheckBox = (CheckBox) findViewById(R.id.checkBox);
  }

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

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

1 Answer

Ben Deitch
STAFF
Ben Deitch
Treehouse Teacher
Ben Deitch
Ben Deitch
Treehouse Teacher

Hey Kenneth!

Not sure if you've solved this yet, but 'getBoolean' actually has two parameters. The 2nd parameter is just a default value in case the specified SharedPreference doesn't exist yet.

mSharedPreferences.getBoolean(KEY_CHECKBOX, true);

Kenneth Phillips
Kenneth Phillips
Courses Plus Student 10,188 Points

So sorry it took so long to respond. When I put this in it says that Task Two is no longer passing.

Ben Deitch
Ben Deitch
Treehouse Teacher
Ben Deitch
Ben Deitch
Treehouse Teacher

Ah, you also need to move the mCheckBox initialization to before we start using it :)

This works for me: 

  @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();

    boolean isChecked = mSharedPreferences.getBoolean(KEY_CHECKBOX, false);
    mCheckBox.setChecked(isChecked);
  }

You'll also want to change your 'onPause' function to store whether or not 'mCheckBox' is checked: 

  @Override
  protected void onPause() {
    super.onPause();
    mEditor.putBoolean(KEY_CHECKBOX, mCheckBox.isChecked());
    mEditor.apply();
  }