package com.example.preference;import android.os.Bundle;import android.preference.CheckBoxPreference;import android.preference.PreferenceActivity;import android.preference.PreferenceManager;import android.widget.Toast;public class MainActivity extends PreferenceActivity {    PreferenceManager pm;    CheckBoxPreference checkbox;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        addPreferencesFromResource(R.layout.activity_main);        pm = getPreferenceManager();        checkbox = (CheckBoxPreference) pm.findPreference("checkbox");        boolean n = checkbox.isChecked();        Toast.makeText(getApplicationContext(), "now" + n, Toast.LENGTH_SHORT).show();    }}