产生原因:
1. TODO
方法声明：
@kotlin.internal.InlineOnly
public inline fun TODO(): Nothing = throw NotImplementedError()
方法使用：
fun test(){
TODO("Not implemented")
}
方法说明：有点类似于java的//todo,但是不同的是，因为它的方法告诉我们，它会抛出一个异常，也就是上面这个方法会导致程序崩溃。它的好处是：配合IDE自动声明的TODO, 会强制开发者去实现这个TODO或者删除它。
我出该异常时的代码:在给EditText添加一个addTextChangedListener监听时,以为和平时写Java的时候,不用管TODO,也就没有注释掉,在Kotlin代码上,运行就出现了NotImplementedError异常.所以要解决这个问题,值需要删除掉TODO就可以了.
如下：（删除TODO即可）
override fun onActivityPaused(activity: Activity?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivityResumed(activity: Activity?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivityStarted(activity: Activity?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivityDestroyed(activity: Activity?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivitySaveInstanceState(activity: Activity?, outState: Bundle?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivityStopped(activity: Activity?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
override fun onActivityCreated(activity: Activity?, savedInstanceState: Bundle?) {
TODO("not implemented")//To change body of created functions use File | Settings | File Templates.
}
