Android: copy / duplicate SharedPreferences

Question

Is there a way to copy or duplicate a SharedPreference? Or do I need to get each variable from one, and then put them in another?

Answer 1

Try something like this:

//sp1 is the shared pref to copy to SharedPreferences.Editor ed = sp1.edit(); SharedPreferences sp = Sp2; //The shared preferences to copy from ed.clear(); // This clears the one we are copying to, but you don't necessarily need to do that. //Cycle through all the entries in the sp for(Entry<String,?> entry : sp.getAll().entrySet()){ Object v = entry.getValue(); String key = entry.getKey(); //Now we just figure out what type it is, so we can copy it. // Note that i am using Boolean and Integer instead of boolean and int. // That because the Entry class can only hold objects and int and boolean are primatives. if(v instanceof Boolean) // Also note that i have to cast the object to a Boolean // and then use .booleanValue to get the boolean ed.putBoolean(key, ((Boolean)v).booleanValue()); else if(v instanceof Float) ed.putFloat(key, ((Float)v).floatValue()); else if(v instanceof Integer) ed.putInt(key, ((Integer)v).intValue()); else if(v instanceof Long) ed.putLong(key, ((Long)v).longValue()); else if(v instanceof String) ed.putString(key, ((String)v)); } ed.commit(); //save it. 

Hope this helps.

Answer 2

Here is a version that also supports row sets.

 public static void copySharedPreferences(SharedPreferences fromPreferences, SharedPreferences toPreferences) { copySharedPreferences(fromPreferences, toPreferences, true); } public static void copySharedPreferences(SharedPreferences fromPreferences, SharedPreferences toPreferences, boolean clear) { SharedPreferences.Editor editor = toPreferences.edit(); if (clear) { editor.clear(); } copySharedPreferences(fromPreferences, editor); editor.commit(); } @TargetApi(Build.VERSION_CODES.HONEYCOMB) @SuppressWarnings({"unchecked", "ConstantConditions"}) public static void copySharedPreferences(SharedPreferences fromPreferences, SharedPreferences.Editor toEditor) { for (Map.Entry<String, ?> entry : fromPreferences.getAll().entrySet()) { Object value = entry.getValue(); String key = entry.getKey(); if (value instanceof String) { toEditor.putString(key, ((String) value)); } else if (value instanceof Set) { toEditor.putStringSet(key, (Set<String>) value); // EditorImpl.putStringSet already creates a copy of the set } else if (value instanceof Integer) { toEditor.putInt(key, (Integer) value); } else if (value instanceof Long) { toEditor.putLong(key, (Long) value); } else if (value instanceof Float) { toEditor.putFloat(key, (Float) value); } else if (value instanceof Boolean) { toEditor.putBoolean(key, (Boolean) value); } } } 

Answer 3

Kotlin Version:

 fun SharedPreferences.copyTo(dest: SharedPreferences) = with(dest.edit()) { for (entry in all.entries) { val value = entry.value ?: continue val key = entry.key when (value) { is String -> putString(key, value) is Set<*> -> putStringSet(key, value as Set<String>) is Int -> putInt(key, value) is Long -> putLong(key, value) is Float -> putFloat(key, value) is Boolean -> putBoolean(key, value) else -> error("Unknown value type: $value") } } apply() } 

Using:

 val prefs1 = getSharedPreferences("test1", MODE_PRIVATE) val prefs2 = getSharedPreferences("test2", MODE_PRIVATE) prefs1.copyTo(prefs2)