每日一道面试题#1 自定义 Handler 时如何有效地避免内存泄漏问题？

private var mHandler: Handler? = WithoutLeakHandler(this)

companion object {
        const val CODE_LOAD_DATA: Int   = 101
        private class WithoutLeakHandler( activity: EditAddressActivity) : Handler(){
            private var mActivity: WeakReference<EditAddressActivity> = WeakReference(activity)

            override fun handleMessage(msg: Message) {
                super.handleMessage(msg)
                val activity = mActivity.get()
                when(msg.what){

                    CODE_LOAD_DATA -> {
                        //data load started

                    
                }
            }
        }
    }
    
......

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        mHandler?.sendEmptyMessage(CODE_LOAD_DATA)
    }

override fun onDestroy() {
        super.onDestroy()
        if (mHandler != null){
            mHandler?.removeCallbacksAndMessages(null)
        }
    }