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

Posted by REINHARD CHEFU
REINHARD CHEFU
5,163 Points

activity lifecycle

Lastly, retrieve the saved value in onCreate and set the state of the CheckBox. If there isn't a saved value, the CheckBox should NOT be checked. Hint: Use the setChecked method.

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

public class MainActivity extends Activity {
  private static final String PREFS_FILE = "com.packagename.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);

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

    String checkBoxString = mSharedPreferences.getString(KEY_CHECKBOX, "");
    mCheckBox.setChecked(checkBoxString);

  }

  @Override
    protected void onPause() {
        super.onPause();
//I am lost around here
boolean checked = mCheckBox.isChecked();
  mEditor.putBoolean("key_checkbox",true);
      mEditor.apply();


    }

}

1 Answer

Seth Kroger
Seth Kroger
56,414 Points
Seth Kroger
Seth Kroger
56,414 Points

There are a few things here: 1) you are saving a boolean to SharedPreferences but retrieving a String. The items should both be the same type. 2) You are using different keys to store and retrieve the data, one lowercased and the other all caps. They should be exactly the same. 3) You are always storing true as the checkbox state, instead of the actual state of the checkbox.

REINHARD CHEFU
REINHARD CHEFU
5,163 Points

thanks for the help but I am still not getting the concept.....can u explain more