Question

更改首选项时，

onSharedPreferenceChanged未被调用，我使用以下代码：

compile 'net.sourceforge.htmlunit:htmlunit:2.22'

pref.xml

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_settings2);
 getFragmentManager().beginTransaction().replace(android.R.id.content, new Frag()).commit();
}

public static class Frag extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.pref);
        getPreferenceManager().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
    }
    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        System.out.println(key);
    }
}

当我更改SwitchPreference时，它没有调用onSharedPreferenceChanged，为什么？

Answer 1

代码SwitchPreference没有设置android：key：

<SwitchPreference android:title="show floating touch" android:defaultValue="false"></SwitchPreference>

将其更改为：

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <SwitchPreference android:key="show_float_toucher" android:title="show floating toucher" android:defaultValue="false"/>
</PreferenceScreen>

工作

Answer 2

我发现有同样问题的以下链接很有用：

How to listen for preference changes within a PreferenceFragment?

代码示例：

public class PrefActivity extends Activity  {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    getFragmentManager().beginTransaction()
            .replace(android.R.id.content, new PrefFragment()).commit();

}

public static class PrefFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
    @Override
    public void onResume() {
        super.onResume();
        getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
    }

    @Override
    public void onPause() {
        getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
        super.onPause();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // set xml 
        addPreferencesFromResource(R.xml.pref);

        // set texts correctly
        onSharedPreferenceChanged(null, "");

    }

    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {

        if (key.equals("show_float_toucher"))
        {
           //TODO                

        }
    }
}

}

提示：检查你minSdkVersion！

最好的问候！

PreferenceFragment不会在onSharedPreferenceChanged上调用

2 个答案: