Android: Copy/Duplicate SharedPreferences

Question

Có cách nào để sao chép hoặc sao chép SharedPreference không? Hoặc tôi sẽ cần phải nhận được mỗi biến từ một biến và sau đó đặt chúng vào một biến khác?

Answer 1

Hãy thử như thế này:

//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's 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

Đây là phiên bản cũng hỗ trợ các bộ chuỗi.

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); 
     } 
    } 
}