Java Android:Handler.postdayed不'；停不下来

我无法停止下面示例中的handler.postDelayed。它在1秒后继续工作，在开关关闭时不会停止：

    mySwitch.setChecked(false);
    mySwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            final Handler handler = new Handler();

            final Runnable r = new Runnable() {
                public void run() {
                    myClient.SendData("AA");
                    handler.postDelayed(this, 1000);
                }
            };
            if (isChecked){
                handler.postDelayed(r, 1000);
            }
            else {
                handler.removeCallbacks(r);
            }
        }
    });

并且在开关关闭时不会停止：

    mySwitch.setChecked(false);
    mySwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            final Handler handler = new Handler();

            final Runnable r = new Runnable() {
                public void run() {
                    myClient.SendData("AA");
                    handler.postDelayed(this, 1000);
                }
            };
            if (isChecked){
                handler.postDelayed(r, 1000);
            }
            else {
                handler.removeCallbacks(r);
            }
        }
    });

这是因为每次调用回调时都要实例化r。移动

   final Runnable r = new Runnable() {
        public void run() {
             myClient.SendData("AA");
             handler.postDelayed(this, 1000);
        }
   };

在回调之外。在方法或类的范围内