AndroidSettingsAccessor.java

package de.skycoder42.qtmvvm.core;

import java.util.Set;

import android.content.Context;
import android.content.SharedPreferences;

import android.preference.PreferenceManager;

class AndroidSettingsAccessor {
    private long address = 0;
    private SharedPreferences preferences = null;
    private SharedPreferences.Editor editor = null;
    private Listener listener = new Listener();

    private class Listener implements SharedPreferences.OnSharedPreferenceChangeListener {
        @Override
        public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
            if(address != 0 && preferences.equals(sharedPreferences))
                callback(address, key);
        }
    }

    private static native void callback(long address, Object key);

    public AndroidSettingsAccessor(Context context, long address) {
        this.address = address;
        preferences = PreferenceManager.getDefaultSharedPreferences(context);
        preferences.registerOnSharedPreferenceChangeListener(listener);
    }

    public AndroidSettingsAccessor(Context context, String name, int mode, long address) {
        this.address = address;
        preferences = context.getSharedPreferences(name, mode);
        preferences.registerOnSharedPreferenceChangeListener(listener);
    }

    public void unref() {
        address = 0;
        preferences.unregisterOnSharedPreferenceChangeListener(listener);
        listener = null;
        sync();
    }

    public boolean contains(String key) {
        return preferences.contains(key);
    }

    public Object load(String key) {
        return preferences.getAll().get(key);
    }

    public boolean save(String key, boolean value) {
        boolean res = beginEdit();
        editor.putBoolean(key, value);
        return res;
    }

    public boolean save(String key, int value) {
        boolean res = beginEdit();
        editor.putInt(key, value);
        return res;
    }

    public boolean save(String key, long value) {
        boolean res = beginEdit();
        editor.putLong(key, value);
        return res;
    }

    public boolean save(String key, float value) {
        boolean res = beginEdit();
        editor.putFloat(key, value);
        return res;
    }

    public boolean save(String key, String value) {
        boolean res = beginEdit();
        editor.putString(key, value);
        return res;
    }

    public boolean save(String key, Set<String> value) {
        boolean res = beginEdit();
        editor.putStringSet(key, value);
        return res;
    }

    public boolean remove(String key) {
        boolean res = beginEdit();
        editor.remove(key);
        return res;
    }

    public void sync() {
        if(editor != null) {
            editor.apply();
            editor = null;
        }
    }

    private boolean beginEdit() {
        if(editor != null)
            return false;
        else {
            editor = preferences.edit();
            return true;
        }
    }
}