多亏了这个SO答案，我得出了以下结论，在我的情况下，当滚动浏览ViewPager的片段时，它很好地工作。。。

private void hideKeyboard() {   
    // Check if no view has focus:
    View view = this.getCurrentFocus();
    if (view != null) {
        InputMethodManager inputManager = (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE);
        inputManager.hideSoftInputFromWindow(view.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
    }
}

private void showKeyboard() {   
    // Check if no view has focus:
    View view = this.getCurrentFocus();
    if (view != null) {
        InputMethodManager inputManager = (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE);
        inputManager.showSoftInput(view, InputMethodManager.SHOW_IMPLICIT);
    }
}

Kotlin版本

val imm: InputMethodManager = getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager
//Hide:
imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0);
//Show
imm.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0);

public void hideKeyboard() 
{
    if(getCurrentFocus()!=null) 
    {
        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
        inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
    }
}


public void showKeyboard(View mView) {
    InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
    mView.requestFocus();
    inputMethodManager.showSoftInput(mView, 0);
}

下面是隐藏和显示方法。

科特林

fun hideKeyboard(activity: Activity) {
    val v = activity.currentFocus
    val imm = activity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    assert(v != null)
    imm.hideSoftInputFromWindow(v!!.windowToken, InputMethodManager.HIDE_NOT_ALWAYS)
}

private fun showKeyboard(activity: Activity) {
    val v = activity.currentFocus
    val imm = activity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    assert(v != null)
    imm.showSoftInput(v, InputMethodManager.SHOW_IMPLICIT)
}

Java

public static void hideKeyboard(Activity activity) {
    View v = activity.getCurrentFocus();
    InputMethodManager imm = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);
    assert imm != null && v != null;
    imm.hideSoftInputFromWindow(v.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
}

private static void showKeyboard(Activity activity) {
    View v = activity.getCurrentFocus();
    InputMethodManager imm = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);
    assert imm != null && v != null;
    imm.showSoftInput(v, InputMethodManager.SHOW_IMPLICIT);
}

一些科特林代码：

从“活动”中隐藏键盘：

(currentFocus ?: View(this))
            .apply { (getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager)
                        .hideSoftInputFromWindow(windowToken, 0) }

试试这个

简单，您可以在活动中调用

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

在您的主活动中调用

 hideKeyboardwithoutPopulate(MainActivity.this);