我有一个我一直无法弄清楚的问题。我有一个从保存在 SharedPreferences 中的 ArrayList 加载的微调器。我允许用户通过一个单独的类 startActivityForResult 中的 PreferenceActivity 修改微调器名称。它可以工作，但除非应用程序关闭然后重新打开，否则我无法让微调器使用新名称刷新自身。
当用户使用后退键关闭编辑名称窗口时，结果代码和 result_ok 信息将正确传回。这是我无法弄清楚的地方。我知道我需要使用 NotifyDataSetChanged 但我不知道该怎么做，因为修改是在一个单独的类中进行的，而不是在 OnItemSelectedListener 中，就像 StackOverflow 上的许多问题的答案建议刷新微调器数据一样。
这是我的微调器代码：
private ArrayAdapter<String> adapter1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
/* enable hardware acceleration on Android >= 3.0 */
final int FLAG_HARDWARE_ACCELERATED = WindowManager.LayoutParams.class
.getDeclaredField("FLAG_HARDWARE_ACCELERATED").getInt(null);
getWindow().setFlags(FLAG_HARDWARE_ACCELERATED,
FLAG_HARDWARE_ACCELERATED);
} catch (Exception e) {
}
checkPreferences();
setContentView(R.layout.main);
this.findViewById(R.id.label_mode).setOnClickListener(this);
this.findViewById(R.id.label_clear).setOnClickListener(this);
this.findViewById(R.id.label_data).setOnClickListener(this);
this.findViewById(R.id.label_wifi).setOnClickListener(this);
this.findViewById(R.id.label_roam).setOnClickListener(this);
this.findViewById(R.id.label_vpn).setOnClickListener(this);
this.findViewById(R.id.label_invert).setOnClickListener(this);
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(getApplicationContext());
// create the spinner
spinner = (Spinner) findViewById(R.id.spinner);
// profile names for spinner
final List<String> profilestring = new ArrayList<String>();
profilestring.add(prefs.getString("default",
getString(R.string.defaultprofile)));
profilestring.add(prefs.getString("profile1",
getString(R.string.profile1)));
profilestring.add(prefs.getString("profile2",
getString(R.string.profile2)));
profilestring.add(prefs.getString("profile3",
getString(R.string.profile3)));
profilestring.add(prefs.getString("profile4",
getString(R.string.profile4)));
profilestring.add(prefs.getString("profile5",
getString(R.string.profile5)));
profileposition = profilestring
.toArray(new String[profilestring.size()]);
// adapter for spinner
adapter1 = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_dropdown_item, profileposition);
adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter1);
spinner.setSelection(prefs.getInt("itemPosition", 0));
spinner.post(new Runnable() {
public void run() {
spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent,
View view, int position, long id) {
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = prefs.edit();
int index = parent.getSelectedItemPosition();
if (index == 0) {
editor.putInt("itemPosition", index);
editor.commit();
LoadDefaultProfile();
}
if (index == 1) {
editor.putInt("itemPosition", index);
editor.commit();
LoadProfile1();
}
if (index == 2) {
editor.putInt("itemPosition", index);
editor.commit();
LoadProfile2();
}
if (index == 3) {
editor.putInt("itemPosition", index);
editor.commit();
LoadProfile3();
}
if (index == 4) {
editor.putInt("itemPosition", index);
editor.commit();
LoadProfile4();
}
if (index == 5) {
editor.putInt("itemPosition", index);
editor.commit();
LoadProfile5();
}
}
public void onNothingSelected(AdapterView<?> parent) {
// do nothing
}
});
}
});
然后我设置我的选择并使用 spinner.post(New Runnable) 运行微调器。
我的偏好屏幕非常简单。
<?xml version="1.0" encoding="utf-8"?>
<EditTextPreference
android:key="default"
android:summary="Edit name for Default Profile"
android:title="@string/defaultprofile" />
<EditTextPreference
android:key="profile1"
android:summary="Edit name for profile1"
android:title="@string/profile1" />
<EditTextPreference
android:key="profile2"
android:summary="Edit name for profile2"
android:title="@string/profile2" />
<EditTextPreference
android:key="profile3"
android:summary="Edit name for profile3"
android:title="@string/profile3" />
<EditTextPreference
android:key="profile4"
android:summary="Edit name for profile4"
android:title="@string/profile4" />
<EditTextPreference
android:key="profile5"
android:summary="Edit name for profile5"
android:title="@string/profile5" />
编辑名称类
public class EditProfileNames extends PreferenceActivity implements
OnSharedPreferenceChangeListener {
@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.layout.prefs);
PreferenceManager.setDefaultValues(EditProfileNames.this,
R.layout.prefs, false);
for (int i = 0; i < getPreferenceScreen().getPreferenceCount(); i++) {
initSummary(getPreferenceScreen().getPreference(i));
}
}
@SuppressWarnings("deprecation")
@Override
protected void onResume() {
super.onResume();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences()
.registerOnSharedPreferenceChangeListener(this);
}
@SuppressWarnings("deprecation")
@Override
protected void onPause() {
super.onPause();
// Unregister the listener whenever a key changes
getPreferenceScreen().getSharedPreferences()
.unregisterOnSharedPreferenceChangeListener(this);
}
@SuppressWarnings("deprecation")
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
String key) {
updatePrefSummary(findPreference(key));
}
private void initSummary(Preference p) {
if (p instanceof PreferenceCategory) {
PreferenceCategory pCat = (PreferenceCategory) p;
for (int i = 0; i < pCat.getPreferenceCount(); i++) {
initSummary(pCat.getPreference(i));
}
} else {
updatePrefSummary(p);
}
}
private void updatePrefSummary(Preference p) {
if (p instanceof ListPreference) {
ListPreference listPref = (ListPreference) p;
p.setSummary(listPref.getEntry());
}
if (p instanceof EditTextPreference) {
EditTextPreference editTextPref = (EditTextPreference) p;
p.setSummary(editTextPref.getText());
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK)) {
resultOk();
}
return super.onKeyDown(keyCode, event);
}
/**
* Set the activity result to RESULT_OK and terminate this activity.
*/
private void resultOk() {
final Intent response = new Intent(Api.PREF_PROFILES);
setResult(RESULT_OK, response);
finish();
}
}
那么我该怎么做才能刷新微调器？我知道如果在 OnItemSelectedListener 中进行了更改，我可以做到这一点，但因为它是一个完全不同的类，所以我现在迷失了。
谢谢！