关于activity.this与getApplicationContext()的区别
new AlertDialog.Builder(getApplicationContext())时发生错误:
E/AndroidRuntime(5844): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
于是查了查:
getApplicationContext() 生命周期是整个应用,应用摧毁它才摧毁 Activity.this的context属于activity ,activity 摧毁他就摧毁
activity.this要返回一个activity,而getApplicationContext()就不一定返回一个activity