How to transfer sharedpreferences file from intern

问题:

How to copy sharedpreferences to external storage keeping xml format, so later it could be possible to share preferences.

Tried to read sharedpreferences and save as a string into file, created JSON type of a string, but I need an xml. Thought of traversing through app's internal storage and copy file and put it in external storage, but that could be too complex.

Just really would want to know if there is an easy and sensible way to transfer `sharedpreferences.

回答1:

Use this code,

SharedPreferences preferences=this.getSharedPreferences("com.example.application", Context.MODE_PRIVATE);
Map<String,?> keys = preferences.getAll();
Properties properties = new Properties();
for(Map.Entry<String,?> entry : keys.entrySet()){
    String key = entry.getKey();
    String value = entry.getValue().toString();
    properties.setProperty(key, value);      
}
try {
    File file = new File("externalPreferences.xml");
    FileOutputStream fileOut = new FileOutputStream(file);
    properties.storeToXML(fileOut, "External Preferences");
    fileOut.close();
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

and to retrive use this,

try {
    File file = new File("externalPreferences.xml");
    FileInputStream fileInput = new FileInputStream(file);
    Properties properties = new Properties();
    properties.loadFromXML(fileInput);
    fileInput.close();

    Enumeration enuKeys = properties.keys();
    SharedPreferences.Editor editor = preferences.edit();
    while (enuKeys.hasMoreElements()) {
        String key = (String) enuKeys.nextElement();
        String value = properties.getProperty(key);
        editor.putString(key, value);
        editor.commit();
    }
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

NOTE You can handle only String type preferences with this code,