与Android 10（API 29）一起工作

val activityView = activity?.window?.decorView?.rootView
activityView?.let {
    val imm = activity?.getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
    imm?.hideSoftInputFromWindow(it.windowToken, 0)
}

感谢上帝，它在11年后得到了官方支持

首先将依赖实现“androidx.core:core-ktx:1.7.0”添加到appgradle

然后从ViewCompat或WindowCompat类获取InsetsController。

最后使用InsetsController的hide（）和show（）函数

已编辑添加对Dialog的支持。在BottomSheetDialog中提供@隆德夫。使用更安全的方式获取活动，而不是直接从上下文中强制转换。

import android.app.Activity
import android.app.Dialog
import android.content.Context
import android.content.ContextWrapper
import android.view.View
import androidx.core.view.ViewCompat
import androidx.core.view.WindowCompat
import androidx.core.view.WindowInsetsCompat
import androidx.fragment.app.Fragment

fun View.showKeyboard() = ViewCompat.getWindowInsetsController(this)?.show(WindowInsetsCompat.Type.ime())
fun View.hideKeyboard() = ViewCompat.getWindowInsetsController(this)?.hide(WindowInsetsCompat.Type.ime())

fun Dialog.showKeyboard() = window?.decorView?.showKeyboard()
fun Dialog.hideKeyboard() = window?.decorView?.hideKeyboard()

fun Context.showKeyboard() = getActivity()?.showKeyboard()
fun Context.hideKeyboard() = getActivity()?.hideKeyboard()

fun Fragment.showKeyboard() = activity?.showKeyboard()
fun Fragment.hideKeyboard() = activity?.hideKeyboard()

fun Activity.showKeyboard() = WindowCompat.getInsetsController(window, window.decorView)?.show(WindowInsetsCompat.Type.ime())
fun Activity.hideKeyboard() = WindowCompat.getInsetsController(window, window.decorView)?.hide(WindowInsetsCompat.Type.ime())

fun Context.getActivity(): Activity? {
    return when (this) {
        is Activity -> this
        is ContextWrapper -> this.baseContext.getActivity()
        else -> null
    }
}

下面是旧的anwser

下面是github上的简单项目

import android.app.Activity
import android.app.Dialog
import android.content.Context
import android.content.ContextWrapper
import android.view.View
import androidx.core.view.ViewCompat
import androidx.core.view.WindowCompat
import androidx.core.view.WindowInsetsCompat
import androidx.fragment.app.Fragment

fun View.showKeyboard() = ViewCompat.getWindowInsetsController(this)?.show(WindowInsetsCompat.Type.ime())
fun View.hideKeyboard() = ViewCompat.getWindowInsetsController(this)?.hide(WindowInsetsCompat.Type.ime())

fun Dialog.showKeyboard() = window?.decorView?.showKeyboard()
fun Dialog.hideKeyboard() = window?.decorView?.hideKeyboard()

fun Context.showKeyboard() = getActivity()?.showKeyboard()
fun Context.hideKeyboard() = getActivity()?.hideKeyboard()

fun Fragment.showKeyboard() = activity?.showKeyboard()
fun Fragment.hideKeyboard() = activity?.hideKeyboard()

fun Activity.showKeyboard() = WindowCompat.getInsetsController(window, window.decorView)?.show(WindowInsetsCompat.Type.ime())
fun Activity.hideKeyboard() = WindowCompat.getInsetsController(window, window.decorView)?.hide(WindowInsetsCompat.Type.ime())

fun Context.getActivity(): Activity? {
    return when (this) {
        is Activity -> this
        is ContextWrapper -> this.baseContext.getActivity()
        else -> null
    }
}

 fun hideKeyboard(appCompatActivity: AppCompatActivity) {
        val view = appCompatActivity.currentFocus
        val imm = appCompatActivity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        imm.hideSoftInputFromWindow(view.windowToken, 0)
    }

在Kotlin试试这个

 private fun hideKeyboard(){
    val imm = activity!!.getSystemService(INPUT_METHOD_SERVICE) as InputMethodManager
    imm.hideSoftInputFromWindow(activity!!.currentFocus!!.windowToken, 0)
}

在Java中尝试

 private void hideKeyboard(){
  InputMethodManager imm =(InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
  imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
}

Android 11中有一个名为WindowInsetsController的新API，应用程序可以从任何视图访问控制器，通过它我们可以使用hide（）和show（）方法

val controller = view.windowInsetsController

// Show the keyboard (IME)
controller.show(Type.ime())

// Hide the keyboard
controller.hide(Type.ime())

看见https://developer.android.com/reference/android/view/WindowInsetsController

Meier的解决方案也适用于我。在我的例子中，我的应用程序的顶层是一个选项卡宿主，我想在切换选项卡时隐藏关键字-我从选项卡宿主视图获取窗口令牌。

tabHost.setOnTabChangedListener(new OnTabChangeListener() {
    public void onTabChanged(String tabId) {
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(tabHost.getApplicationWindowToken(), 0);
    }
}