我正在开发一款具有一些设置的Android应用。它仍然是一个草稿,但我遇到了一个我不能成功解决的问题:我创建了一个示例设置活动(使用Android开发人员指南建议的PreferenceFragment),我添加了一个"恢复默认设置"按钮。但是,此按钮仅部分有效 - 它仅恢复编辑文本首选项,但不恢复其余部分。我的意图是,当我按下按钮时,所有首选项都应恢复为preferences.xml文件中显示的值。
这里是代码:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
}
public void applyCoF(View view) {
}
public void changeSettings(View view) {
Intent settingsIntent = new Intent(this, SettingsActivity.class);
startActivity(settingsIntent);
}
}
public class SettingsActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getFragmentManager().beginTransaction().replace(android.R.id.content, new SettingsFragment()).commit();
}
public static class SettingsFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
Preference button = findPreference(getString(R.string.restoreDefaultSettingsButton));
button.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
@Override
public boolean onPreferenceClick(Preference preference) {
//code for what you want it to do
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case DialogInterface.BUTTON_POSITIVE:
//Yes button clicked
restoreDefaultSettings();
break;
case DialogInterface.BUTTON_NEGATIVE:
//No button clicked
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle(R.string.restoreDefaultSettingsDialogTitle);
builder.setMessage(R.string.restoreDefaultSettingsDialogText).
setPositiveButton("Yes", dialogClickListener).
setNegativeButton("No", dialogClickListener).
show();
return true;
}
});
}
private void restoreDefaultSettings() {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.apply();
PreferenceManager.setDefaultValues(getActivity(), R.xml.preferences, true);
}
@Override
public void onResume() {
super.onResume();
for (int i = 0; i < getPreferenceScreen().getPreferenceCount(); ++i) {
Preference preference = getPreferenceScreen().getPreference(i);
if (preference instanceof PreferenceGroup) {
PreferenceGroup preferenceGroup = (PreferenceGroup) preference;
for (int j = 0; j < preferenceGroup.getPreferenceCount(); ++j) {
Preference singlePref = preferenceGroup.getPreference(j);
updatePreference(singlePref, singlePref.getKey());
}
} else {
updatePreference(preference, preference.getKey());
}
}
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
updatePreference(findPreference(key), key);
}
private void updatePreference(Preference preference, String key) {
if (preference == null || preference instanceof CheckBoxPreference) {
return;
}
if (preference instanceof ListPreference) {
ListPreference listPreference = (ListPreference) preference;
listPreference.setSummary(listPreference.getEntry());
return;
}
SharedPreferences sharedPrefs = getPreferenceManager().getSharedPreferences();
preference.setSummary(sharedPrefs.getString(key, "Default"));
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference
android:defaultValue="true"
android:key="check_box_preference_1"
android:title="Check box preference"/>
<EditTextPreference
android:defaultValue="DEFAULT EDIT TEXT"
android:key="edit_text_preference_1"
android:selectAllOnFocus="true"
android:singleLine="true"
android:title="Edit text preference"/>
<ListPreference
android:defaultValue="DEFAULT LIST"
android:entries="@array/list_preference_entry_values"
android:entryValues="@array/list_preference_entries"
android:key="list_preference_1"
android:title="List preference"/>
<Preference android:title="Restore default values"
android:summary=""
android:key="@string/restoreDefaultSettingsButton"/>
</PreferenceScreen>
答案 0 :(得分:1)
我有一个类似的问题-我的EditTextPreferences更改了,但是当我单击它们时,它显示了旧值。当我关闭偏好设置屏幕并返回时,一切都很好。
我解决了这个问题,并验证了其他首选项的工作原理相同,但是您看到的方式不同。当您重新打开首选项屏幕时,将F.E. CheckBoxPreference还原为默认值。但单击“恢复默认设置”后,该按钮将无法正常工作,因为它不会刷新代码中的首选项屏幕。
我只是将其修改为:
private void restoreDefaultSettings() {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.apply();
PreferenceManager.setDefaultValues(getActivity(), R.xml.pref, true);
getPreferenceScreen().removeAll();
onCreatePreferences(null,null); //or onCreate(null) in your code
}
我不知道这是最好的解决方案,但是它可以工作