By Romain Guy From the Question Asked Here, Whatever the maximum length of a Java string is. So something like Integer.MAX_VALUE chars. I suppose while SharedPreference is an XML file stored with One Tag if you store only One Pair/Object. So there is no limit to write String in that if you think like you … Read more
You can save a byte array in SharedPreferences by using android.util.Base64. For saving: String saveThis = Base64.encodeToString(array, Base64.DEFAULT); For loading: byte[] array = Base64.decode(stringFromSharedPrefs, Base64.DEFAULT);
It is worth reviewing the sources that show that a Context instance (be it an Activity or an Application instance) share the same static map HashMap<String, SharedPreferencesImpl>. So whenever you request an instance of SharedPreferences by the same name via Context.getSharedPreferences(name, mode) you get the same instance since it first checks if the map already … Read more
SharedPreferences has a contains(String key) method, which can be used to check if an entry with the given key exists. http://developer.android.com/reference/android/content/SharedPreferences.html
You can create your own String representation of the array like this: StringBuilder sb = new StringBuilder(); for (int i = 0; i < playlists.length; i++) { sb.append(playlists[i]).append(“,”); } prefsEditor.putString(PLAYLISTS, sb.toString()); Then when you get the String from SharedPreferences simply parse it like this: String[] playlists = playlist.split(“,”); This should do the job.
Try it this way: final String eulaKey = “mykey”; Context mContext = getApplicationContext(); mPrefs = mContext.getSharedPreferences(“myAppPrefs”, Context.MODE_PRIVATE); SharedPreferences.Editor editor = mPrefs.edit(); editor.putBoolean(eulaKey, true); editor.commit(); in which case you can specify your own preferences file name (myAppPrefs) and can control access persmission to it. Other operating modes include: MODE_WORLD_READABLE MODE_WORLD_WRITEABLE MODE_MULTI_PROCESS
UPDATED ANSWER: Android has released a security library with EncryptedSharedPreferences in their Jetpack library. Edit: With version v1.1.0 you can support Lollipop (API level 21) and above String masterKeyAlias = MasterKeys.getOrCreate(MasterKeys.AES256_GCM_SPEC); SharedPreferences sharedPreferences = EncryptedSharedPreferences.create( “secret_shared_prefs”, masterKeyAlias, context, EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV, EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM ); // use the shared preferences and editor as you normally would SharedPreferences.Editor editor = … Read more
To save and load accurate date, you could use the long (number) representation of a Date object. Example: //getting the current time in milliseconds, and creating a Date object from it: Date date = new Date(System.currentTimeMillis()); //or simply new Date(); //converting it back to a milliseconds representation: long millis = date.getTime(); You can use this … Read more
The OnSharedPreferenceChangeListener gets garbage collected in your case if you use an anonymous class. To solve that problem use the following code in PreferenceActivity to register and unregister a change listener: public class MyActivity extends PreferenceActivity implements OnSharedPreferenceChangeListener { @Override protected void onResume() { super.onResume(); // Set up a listener whenever a key changes getPreferenceScreen().getSharedPreferences() … Read more
Do SharedPreferences.OnSharedPreferenceChangeListener spChanged = new SharedPreferences.OnSharedPreferenceChangeListener() { @Override public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) { // your stuff here } }; In your PreferenceActivity, ie make it a member of your PreferenceActivity class and then do registerOnSharedPreferenceChangeListener(spChanged) in the PreferenceActivity.onCreate() method. That’s what I do and I never have a problem. Else it’s your conditional … Read more