public static void hideSoftKeyboard(Activity activity) {
    InputMethodManager inputMethodManager = (InputMethodManager)  activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
    inputMethodManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0);
}

在调用onTouchListener之后：

findViewById(android.R.id.content).setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        Utils.hideSoftKeyboard(activity);
        return false;
    }
});

public final class UtilsKeyboard {
/**
 * Sets the cursor at the end of this edit text and shows a keyboard
 */
public static void focusKeyboard(@NonNull EditText editText) {
    editText.requestFocus();
    editText.setSelection(editText.getText().length());
    showKeyboard(editText);
}

private static void showKeyboard(@NonNull View view) {
    final InputMethodManager manager = (InputMethodManager) view.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
    if (manager != null) {
        manager.showSoftInput(view, InputMethodManager.SHOW_FORCED);
    }
}

public static boolean hideKeyboard(@NonNull Window window) {
    View view = window.getCurrentFocus();
    return hideKeyboard(window, view);
}

private static boolean hideKeyboard(@NonNull Window window, @Nullable View view) {
    if (view == null) {
        return false;
    }
    InputMethodManager inputMethodManager = (InputMethodManager) window.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
    if (inputMethodManager != null) {
        return inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }
    return false;
}

public static boolean hideKeyboard(@Nullable View view) {
    if (view == null) {
        return false;
    }
    InputMethodManager inputMethodManager = (InputMethodManager) view.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
    if (inputMethodManager != null) {
        return inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }
    return false;
}

/**
 * This will hide the keyboard and unfocus any focused view.
 */
public static void unfocusKeyboard(@NonNull Window window) {
    // When showing the bottom menu, make sure the keyboard isn't and that no view has focus
    hideKeyboard(window);
    final View focused = window.getCurrentFocus();
    if (focused != null) focused.clearFocus();
}}

这是工作。。

只需在函数中传递当前活动实例

 public void isKeyBoardShow(Activity activity) {
    InputMethodManager imm = (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
    if (imm.isActive()) {
        imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0); // hide
    } else {
        imm.toggleSoftInput(0, InputMethodManager.HIDE_IMPLICIT_ONLY); // show
    }
}

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

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);

可以为任何视图创建Extension函数

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

与活动一起使用的示例

window.decorView.hideKeyboard();

与视图一起使用的示例

etUsername.hideKeyboard();

快乐编码。。。