sharedpreferences

问题 From the name alone, I am guessing that Shared Preferences are... shared among apps? That is, even if my app defines and creates them, any app on android can access them. Is this correct? (If this isn't correct, then why does the Data Storage Dev Guide emphasize Internal Storage as "Store private data"?) If this is correct, can I modify this default behavior so that a preference is only visible from the app in which I define and create it? If so, how do I do that? 回答1: If i'm correct you can

问题 From the name alone, I am guessing that Shared Preferences are... shared among apps? That is, even if my app defines and creates them, any app on android can access them. Is this correct? (If this isn't correct, then why does the Data Storage Dev Guide emphasize Internal Storage as "Store private data"?) If this is correct, can I modify this default behavior so that a preference is only visible from the app in which I define and create it? If so, how do I do that? 回答1: If i'm correct you can

问题 I know, this issue has been dealt with in many threads, but I cannot figure out this one. So I set a shared preference like this: SharedPreferences prefs = MainActivity.this.getPreferences(MODE_PRIVATE); SharedPreferences.Editor editor = prefs.edit(); editor.putStringSet(spinnerName, myValueSet ); editor.apply(); I read the preferences like this: SharedPreferences prefs = MainActivity.this.getPreferences(MODE_PRIVATE); Set<String> spinnerValuesSet = null; spinnerValuesSet = prefs.getStringSet

问题 I am having an odd issue in which the SharedPreferences are not being updated upon returning to an app. Here's the scenario: I have two projects that use the same shared preferences. Project1 and Project2. They are separate but related apps. They are signed with the same key and use sharedUserId to share information. Project1 opens Project2. Project2 retrieves the SharedPreferences file and writes to it via this method: Context prefsContext = c.createPackageContext(packageNameOfProject1,

问题 I am using several SharedPreferences to store data in my app. Some preferences are used in a lot of activites. I know that the SharedPreferences are internally backed by a map for fast read-access and written to sdcard when settings are changed. I wonder which way is better if a sharedpreference is accessed by a lot of activies: Instantiate it in every activity using the activity context. Instantiate it in every activity, but using the application context. Put it in e.g. the Application class

问题 I am developing an android app. If I press a back button the state of my application should be saved .What should i use to save the state ..am confused with all of these onPause() , onResume() , or onRestoresavedInstance() ??? which of these should i use to save the state of my application?? For eg when i press exit button my entire app should exit i have used finish() ? public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); s1=

问题 As described here, I am subclassing PreferenceFragment and displaying it inside an Activity. That document explains how to listen for preference changes here, but only if you subclass PreferenceActivity. Since I'm not doing that, how do I listen for preference changes? I've tried implementing OnSharedPreferenceChangeListener in my PreferenceFragment but it does not seem to work ( onSharedPreferenceChanged never seems to get called). This is my code so far: SettingsActivity.java public class

问题 As described here, I am subclassing PreferenceFragment and displaying it inside an Activity. That document explains how to listen for preference changes here, but only if you subclass PreferenceActivity. Since I'm not doing that, how do I listen for preference changes? I've tried implementing OnSharedPreferenceChangeListener in my PreferenceFragment but it does not seem to work ( onSharedPreferenceChanged never seems to get called). This is my code so far: SettingsActivity.java public class

问题 If you look through each picture, from left to right, you'll notice on the last picture on the right, the points for Quiz One goes to 0... this is my problem This is a quiz app that i'm working on, with Android Studio... I am trying to use SharedPreferences, using putInt and getInt methods to put the value of points scored for each quiz into variables, stored under a String name, then part of onCreate is to getInt using the String name referenced in the putInt m ethods... main activity should

问题 If you look through each picture, from left to right, you'll notice on the last picture on the right, the points for Quiz One goes to 0... this is my problem This is a quiz app that i'm working on, with Android Studio... I am trying to use SharedPreferences, using putInt and getInt methods to put the value of points scored for each quiz into variables, stored under a String name, then part of onCreate is to getInt using the String name referenced in the putInt m ethods... main activity should