[英]Android: onSharedPreferenceChanged does not change a summary of PreferenceScreen
我有一個子屏幕:
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="Hra">
<PreferenceScreen
android:key="pref_game_plus_category"
android:title="@string/operation_plus"
android:persistent="false">
<CheckBoxPreference
android:key="pref_game_operation_plus"
android:title="@string/pref_title_operation_plus"
android:defaultValue="true"
/>
我實例化了首選項
public class GamePreferenceActivity extends PreferenceActivity
implements SharedPreferences.OnSharedPreferenceChangeListener {
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
log.debug("onSharedPreferenceChanged(" + key + ")");
PreferenceScreen preferenceScreen = getPreferenceScreen();
...
case "pref_game_operation_plus":
preferenceScreenHelper.setScreenSummary("plus", preferenceScreen, sharedPreferences);
在這里,我檢測復選框的狀態並設置父屏幕副標題:
public void setScreenSummary(String key, PreferenceScreen preferenceScreen, SharedPreferences sharedPreferences) {
boolean value = sharedPreferences.getBoolean("pref_game_operation_" + key, true);
Preference preference = preferenceScreen.findPreference("pref_game_" + key + "_category");
preference.setSummary(value ? R.string.pref_operation_enabled : R.string.pref_operation_disabled);
當我調試此代碼時, "pref_game_plus_category"
已更新其摘要,但是當我返回根首選項時,摘要不會更改。
PS當我重新啟動首選項活動時,摘要反映當前值。 它初始化為:
public void setScreenSummary(String key, Preference preference, SharedPreferences sharedPreferences) {
boolean value = sharedPreferences.getBoolean("pref_game_operation_" + key, true);
preference.setSummary(value ? R.string.pref_operation_enabled : R.string.pref_operation_disabled);
}
更新:摘要首次更新,但后續更改(甚至不同的屏幕)無效。 奇怪的是,我可以看到此偏好的兩次輸入日志,但調試器只停止一次。 我必須深入研究Android資源。
04-23 08:36:46.471 5503-5503/lelisoft.com.lelimath D/l.c.l.a.GamePreferenceActivity: onSharedPreferenceChanged(pref_game_divide_category)
04-23 08:36:48.004 5503-5503/lelisoft.com.lelimath D/l.c.l.a.GamePreferenceActivity: onSharedPreferenceChanged(pref_game_operation_divide)
04-23 08:36:48.006 5503-5503/lelisoft.com.lelimath D/l.c.l.h.PreferenceHelper: pokus
04-23 08:36:48.007 5503-5503/lelisoft.com.lelimath D/l.c.l.a.GamePreferenceActivity: onSharedPreferenceChanged(pref_game_operation_divide)
將setScreenSummary函數更改為以下內容:
public void setScreenSummary(String key, PreferenceScreen preferenceScreen, SharedPreferences sharedPreferences) {
boolean value = sharedPreferences.getBoolean("pref_game_operation_" + key, true);
//instead of getting a reference to preference typecast it to PreferenceScreen
PreferenceScreen preference = (PreferenceScreen) findPreference("pref_game_" + key + "_category");
//now set the summary
preference.setSummary(value ? R.string.pref_operation_enabled : R.string.pref_operation_disabled);
//here comes the important part
//get the listView adapter and call notifyDataSetChanged
//This is necessary to reflect change after coming back from sub-pref screen
((BaseAdapter)getPreferenceScreen().getRootAdapter()).notifyDataSetChanged();
}
我在gitlab PreferenceScreenDemo上有一個演示項目。 您可以檢查整個代碼。 或者您可以直接跳到演示應用程序的這一部分
我注意到你正在監聽OnSharedPreferenceChangeListener
,嘗試監聽/實現OnPreferenceChangeListener
- 然后處理
onPreferenceChange(Preference preference, Object newValue){
...
if(preference.getKey().equals("pref_game_operation_plus")){
boolean enabled = Boolean.parseBoolean(newValue);
preference.setSummary(enabled);
}
...
}
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