3

我不明白为什么我的复选框首选项未保存或未正确读取。我在 AndroidManifest.xml 中有以下代码：

<activity android:name=".Preferences" />

然后在 res/xml/preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen 
    xmlns:android="http://schemas.android.com/apk/res/android"> 
<PreferenceCategory 
    android:title="Preferences">
   <CheckBoxPreference 
       android:title="Always Run"
       android:key="@string/pref_always_run_key" 
       android:summary="Always run it" />
</PreferenceCategory>

在 res/values/strings.xml

<string name="pref_always_run_key">always_run_default</string>

然后我有一个 src/com.name/Preferences.java 文件

public class Preferences extends PreferenceActivity
{
private static final String LOG_TAG = Preferences.class.getSimpleName() + "_LOG";

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.preferences); //5

    //getPreferenceManager().setSharedPreferencesName();

    CheckBoxPreference alwaysRunCheckBox = (CheckBoxPreference)findPreference(getString(R.string.pref_always_run_key));// 8

    alwaysRunCheckBox.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener()
    {

        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue)
        {

            Log.d(LOG_TAG, "User set always run to " + newValue.toString().equals("true"));
            return true;
        }
    });
}
}

然后我在 MainActivity.java 中有一个测试按钮

SharedPreferences prefs = MainActivity.this.getSharedPreferences("com.projname.Preferences", Context.MODE_PRIVATE);
            String defaultAlwaysRunKey = MainActivity.this.getResources().getString(R.string.pref_always_run_key);
            Log.d(LOG_TAG, "Always run key is " + defaultAlwaysRunKey);
            boolean run = prefs.getBoolean(defaultAlwaysRunKey, false);
                            Log.d(LOG_TAG, "It contains the key: " + prefs.contains(defaultAlwaysRunKey));
            Log.d(LOG_TAG, "Always run set to " + run);
Log.d(LOG_TAG, "All the preferences saved are: " + prefs.getAll().toString());

输出总是：

10-25 16:15:50.844: D/MainActivity_LOG(1219): Clicked on test...
10-25 16:15:50.844: D/MainActivity_LOG(1219): Always run key is always_run_default
10-25 16:15:50.844: D/MainActivity_LOG(1219): It contains the key: false
10-25 16:15:50.844: D/MainActivity_LOG(1219): Always run set to false
10-25 16:15:50.855: D/MainActivity_LOG(1219): All the preferences saved are: {}

不管复选框是否被选中。

4

2 回答 2

4

我认为您的问题是您读取的首选项文件不同于您写入的首选项文件。您按名称读取，但写入默认值。

尝试将 MainActivity 分配更改为

SharedPreferences prefs =
   PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
于 2012-12-30T19:49:28.533 回答
4

您忘记使用 SharedPreference 的编辑器并调用commit();编辑器对象的方法。

CheckBoxPreference alwaysRunCheckBox = (CheckBoxPreference)findPreference(getString(R.string.pref_always_run_key));// 8

    alwaysRunCheckBox.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener()
    {

        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue)
        {

            boolean val = Boolean.parseBoolean(newValue.toString());

            Editor e = preference.getEditor();
            e.putBoolean(getString(R.string.pref_always_run_key), val );
            e.commit();
            Log.d(LOG_TAG, "User set always run to " + String.valueOf(val));

            return true;

        }
    });
于 2012-12-23T20:45:27.300 回答