packages/shared_preferences/shared_preferences_android/android/src/main/java/io/flutter/plugins/sharedpreferences/SharedPreferencesPlugin.java

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.plugins.sharedpreferences;

import android.content.Context;
import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.plugin.common.BinaryMessenger;
import io.flutter.plugin.common.MethodChannel;

/** SharedPreferencesPlugin */
public class SharedPreferencesPlugin implements FlutterPlugin {
  private static final String CHANNEL_NAME = "plugins.flutter.io/shared_preferences";
  private MethodChannel channel;
  private MethodCallHandlerImpl handler;

  @SuppressWarnings("deprecation")
  public static void registerWith(io.flutter.plugin.common.PluginRegistry.Registrar registrar) {
    final SharedPreferencesPlugin plugin = new SharedPreferencesPlugin();
    plugin.setupChannel(registrar.messenger(), registrar.context());
  }

  @Override
  public void onAttachedToEngine(FlutterPlugin.FlutterPluginBinding binding) {
    setupChannel(binding.getBinaryMessenger(), binding.getApplicationContext());
  }

  @Override
  public void onDetachedFromEngine(FlutterPlugin.FlutterPluginBinding binding) {
    teardownChannel();
  }

  private void setupChannel(BinaryMessenger messenger, Context context) {
    channel = new MethodChannel(messenger, CHANNEL_NAME);
    handler = new MethodCallHandlerImpl(context);
    channel.setMethodCallHandler(handler);
  }

  private void teardownChannel() {
    handler.teardown();
    handler = null;
    channel.setMethodCallHandler(null);
    channel = null;
  }
}