flutter 插件开发中获取Activity

1.低版本flutter-1.12

通过registerWith(Registrar registrar){}实现注册，通过registrar.activity()即可得到activity；

2.高版本flutter

通过onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {}实现注册，在这里无法获取activity，

需要插件 implement ActivityAware

然后

@Override
  public void onAttachedToActivity(ActivityPluginBinding activityPluginBinding) {
    activity = activityPluginBinding.getActivity();
  }

  @Override
  public void onDetachedFromActivityForConfigChanges() {

  }

  @Override
  public void onReattachedToActivityForConfigChanges(ActivityPluginBinding activityPluginBinding) {
    onAttachedToActivity(activityPluginBinding);
  }

  @Override
  public void onDetachedFromActivity() {

  }