正如here所描述的,我对PreferenceFragment进行了子类化,并将其显示在一个活动中。该文档解释了如何侦听here的首选项更改,但前提是您对PreferenceActivity进行了子类化。既然我没有这样做,我该如何监听首选项的更改呢?
我曾尝试在我的PreferenceFragment中实现OnSharedPreferenceChangeListener,但似乎不起作用(onSharedPreferenceChanged
似乎从未被调用过)。
这是我到目前为止的代码:
SettingsActivity.java
public class SettingsActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Display the fragment as the main content.
getFragmentManager().beginTransaction().replace(android.R.id.content, new SettingsFragment()).commit();
}
}
SettingsFragment.java
public class SettingsFragment extends PreferenceFragment implements OnSharedPreferenceChangeListener
{
public static final String KEY_PREF_EXERCISES = "pref_number_of_exercises";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preferences);
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key)
{
//IT NEVER GETS IN HERE!
if (key.equals(KEY_PREF_EXERCISES))
{
// Set summary to be the user-description for the selected value
Preference exercisesPref = findPreference(key);
exercisesPref.setSummary(sharedPreferences.getString(key, ""));
}
}
}
preferences.xml
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<EditTextPreference
android:defaultValue="15"
android:enabled="true"
android:key="pref_number_of_exercises"
android:numeric="integer"
android:title="Number of exercises" />
</PreferenceScreen>
另外,PreferenceFragment是否是监听首选项更改的正确位置,还是应该在活动中进行监听?
发布于 2012-11-28 10:00:14
我相信你只需要在你的PreferenceFragment
中注册/取消注册Listener
,它就会工作。
@Override
public void onResume() {
super.onResume();
getPreferenceManager().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
}
@Override
public void onPause() {
getPreferenceManager().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
super.onPause();
}
根据您要做的事情,您可能不需要使用侦听器。对首选项的更改将自动提交到SharedPreferences
。
发布于 2013-05-06 22:25:41
antew的解决方案效果很好,你可以在这里看到Android v11的完整偏好活动:
import android.app.Activity;
import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.os.Bundle;
import android.preference.ListPreference;
import android.preference.PreferenceFragment;
public class UserPreferencesV11 extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Display the fragment as the main content.
getFragmentManager().beginTransaction().replace(android.R.id.content,
new PrefsFragment()).commit();
}
public static class PrefsFragment extends PreferenceFragment implements OnSharedPreferenceChangeListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preferences);
// set texts correctly
onSharedPreferenceChanged(null, "");
}
@Override
public void onResume() {
super.onResume();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
}
@Override
public void onPause() {
super.onPause();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
// just update all
ListPreference lp = (ListPreference) findPreference(PREF_YOUR_KEY);
lp.setSummary("dummy"); // required or will not update
lp.setSummary(getString(R.string.pref_yourKey) + ": %s");
}
}
}
发布于 2014-06-24 20:25:52
所有其他答案都是正确的。但我更喜欢这个选项,因为您可以立即获得导致更改的Preference实例。
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Preference pref = findPreference(getString(R.string.key_of_pref));
pref.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
@Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
// do whatever you want with new value
// true to update the state of the Preference with the new value
// in case you want to disallow the change return false
return true;
}
});
}
https://stackoverflow.com/questions/13596250
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