layout: post title: “2019-08-02-怪异bug记录.markdown” date: 2019-08-02 12:11:30 +0800

  1. 空指针

问题描述: 静态变量的初始化被判定为空

java.lang.NullPointerException

Attempt to read from field ‘android.arch.lifecycle.MutableLiveData com.wwt.simple.mantransaction.mainpage.model.MainActivityModel.board’ on a null object reference

class MainActivityModel{ public static MutableLiveData board = new MutableLiveData<>(); }

原因: 堆内容被卸载,需要使用安全的单例模型

  1. selector

问题描述: 点击selector背景无反应

原因: 需要将android:state_pressed=”true”选项放置到前面.