一：在某一个activity中点击任意位置均可以隐藏键盘

val keyboard =getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
//this.currentFocus?.windowToken 是获取当前activity的windowToken
keyboard.hideSoftInputFromWindow(this.currentFocus?.windowToken,0)

二：若输入法已经打开则隐藏，反之则显示

val keyboard = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
keyboard.toggleSoftInput(0,InputMethodManager.HIDE_NOT_ALWAYS)

三：需要接收输入的视图对键盘进行强制打开或隐

val keyboard = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager

//keyboard.isActive是键盘的状态，若是打开的则返回true否则返回false
if (keyboard.isActive){
    //强制关闭
    keyboard.hideSoftInputFromWindow(v.windowToken,0)
}else{
    //打开
    keyboard.showSoftInput(v,InputMethodManager.SHOW_FORCED)

}
 
遇到的问题：keyboard.isActive一直返回的都是True，一直没找出是什么原因，本人的解决方法自己定义一个状态值记录
   键盘的状态

private var isopen = false

val keyboard = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager

//keyboard.isActive是键盘的状态，若是打开的则返回true否则返回false
//
if (isopen){
    Log.v("lfl","关闭键盘")
    //强制关闭
    keyboard.hideSoftInputFromWindow(v.windowToken,0)
    isopen = !isopen
}else{
    Log.v("lfl","打开键盘")
    //打开
    keyboard.showSoftInput(v,InputMethodManager.SHOW_FORCED)
   isopen = !isopen
}