这是我的工作。这是在Kotlin隐藏键盘。

private fun hideKeyboard() {
        val inputManager = activity?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        val focusedView = activity?.currentFocus
        if (focusedView != null) {
            inputManager.hideSoftInputFromWindow(focusedView.windowToken,
                    InputMethodManager.HIDE_NOT_ALWAYS)
        }
    }

下面是如何在Mono for Android（AKA MonoDroid）中实现的

InputMethodManager imm = GetSystemService (Context.InputMethodService) as InputMethodManager;
if (imm != null)
    imm.HideSoftInputFromWindow (searchbox.WindowToken , 0);

如果有人感兴趣的话，我已经为Kotlin写了一个小扩展，但没有太多测试：

fun Fragment.hideKeyboard(context: Context = App.instance) {
    val windowToken = view?.rootView?.windowToken
    windowToken?.let {
        val imm = context.getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager
        imm.hideSoftInputFromWindow(windowToken, 0)
    }
}

App.instance是存储在Application中的静态“this”Application对象

更新：在某些情况下，windowToken为空。我增加了使用反射来检测键盘是否关闭的额外关闭方式

/**
 * If no window token is found, keyboard is checked using reflection to know if keyboard visibility toggle is needed
 *
 * @param useReflection - whether to use reflection in case of no window token or not
 */
fun Fragment.hideKeyboard(context: Context = MainApp.instance, useReflection: Boolean = true) {
    val windowToken = view?.rootView?.windowToken
    val imm = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    windowToken?.let {
        imm.hideSoftInputFromWindow(windowToken, 0)
    } ?: run {
        if (useReflection) {
            try {
                if (getKeyboardHeight(imm) > 0) {
                    imm.toggleSoftInput(0, InputMethodManager.HIDE_NOT_ALWAYS)
                }
            } catch (exception: Exception) {
                Timber.e(exception)
            }
        }
    }
}

fun getKeyboardHeight(imm: InputMethodManager): Int = InputMethodManager::class.java.getMethod("getInputMethodWindowVisibleHeight").invoke(imm) as Int

在某些情况下，除了所有其他方法外，这种方法都可以工作。这节省了我的一天：）

public static void hideSoftKeyboard(Activity activity) {
    if (activity != null) {
        InputMethodManager inputManager = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);
        if (activity.getCurrentFocus() != null && inputManager != null) {
            inputManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0);
            inputManager.hideSoftInputFromInputMethod(activity.getCurrentFocus().getWindowToken(), 0);
        }
    }
}

public static void hideSoftKeyboard(View view) {
    if (view != null) {
        InputMethodManager inputManager = (InputMethodManager) view.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputManager != null) {
            inputManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
        }
    }
}

我使用Kotlin扩展来显示和隐藏键盘。

fun View.showKeyboard() {
  this.requestFocus()
  val inputMethodManager = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
  inputMethodManager.showSoftInput(this, InputMethodManager.SHOW_IMPLICIT)
}

fun View.hideKeyboard() {
  val inputMethodManager = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
  inputMethodManager.hideSoftInputFromWindow(windowToken, 0)
}

我创建了一个布局，部分来自xml，部分来自自定义布局引擎，所有这些都在代码中处理。对我来说，唯一有效的方法是跟踪键盘是否打开，并使用如下键盘切换方法：

public class MyActivity extends Activity
{
    /** This maintains true if the keyboard is open. Otherwise, it is false. */
    private boolean isKeyboardOpen = false;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        LayoutInflater inflater;
        inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View contentView = inflater.inflate(context.getResources().getIdentifier("main", "layout", getPackageName()), null);

        setContentView(contentView);
        contentView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() 
        {
            public void onGlobalLayout() 
            {
                Rect r = new Rect();
                contentView.getWindowVisibleDisplayFrame(r);
                int heightDiff = contentView.getRootView().getHeight() - (r.bottom - r.top);
                if (heightDiff > 100) 
                    isKeyboardVisible = true;
                else
                    isKeyboardVisible = false;
             });
         }
    }

    public void closeKeyboardIfOpen()
    {
        InputMethodManager imm;
        imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        if (isKeyboardVisible)
            imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0);
    }   
}