从SharedPreference设置CheckBoxPreference

Question

我想使用预定义的共享首选项来设置checkBoxPreference的值，并使用checkBoxPreference设置共享首选项。我尝试过这个代码，但是即使我知道"pre_definied_shared_prefs“的存在，checkboxPref也总是以null结束。

final CheckBoxPreference checkboxPref = (CheckBoxPreference) getPreferenceManager().findPreference("pre_defined_shared_prefs");


    checkboxPref.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {            
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            Boolean b = (Boolean) newValue;

            Intent i = getIntent();
            Integer show_num = i.getIntExtra("show_num", -1);
            SettingsManager s = new SettingsManager();
            s.setShowNotification(show_num, b, getApplicationContext());

            return true;
        }
    });

为什么会出现这种情况，我该如何修复它？

Answer 1

我的preference.xml：

<CheckBoxPreference
          android:title="Show Call UI"
          android:defaultValue="true"
          android:summary="Show Call Interface when clicking call button"
          android:key="checkboxPref" />

Rest代码：

final CheckBoxPreference checkboxPref = (CheckBoxPreference) getPreferenceManager().findPreference("checkboxPref");

    checkboxPref.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {            
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            Log.d("MyApp", "Pref " + preference.getKey() + " changed to " + newValue.toString());       
            return true;
        }
    }); 

以下是如何创建新的复选框首选项并将其添加到您希望或查看this的组的示例

public class MyPreferenceActivity extends PreferenceActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.my_preference_activity);

        //fetch the item where you wish to insert the CheckBoxPreference, in this case a PreferenceCategory with key "targetCategory"
        PreferenceCategory targetCategory = (PreferenceCategory)findPreference("targetCategory");

        //create one check box for each setting you need
        CheckBoxPreference checkBoxPreference = new CheckBoxPreference(this);
        //make sure each key is unique  
        checkBoxPreference.setKey("keyName");
        checkBoxPreference.setChecked(true);

        targetCategory.addPreference(checkBoxPreference);
    }
}