添加到Manifest文件中的活动android:windowSoftInputMode=“stateHidden”。例子：

<activity
            android:name=".ui.activity.MainActivity"
            android:label="@string/mainactivity"
            android:windowSoftInputMode="stateHidden"/>

用try-catch包围它，这样键盘就已经关闭，应用程序就不会崩溃：

try{

View view = this.getCurrentFocus();
if (view != null) {  
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
}catch (Exception e)
{
  e.printStackTrace();
}

从碎片移动到碎片时

fun hideKeyboard(activity: Activity?): Boolean {
    val inputManager = activity?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager?
    if (inputManager != null) {
        val currentFocus = activity?.currentFocus
        if (currentFocus != null) {
            val windowToken = currentFocus.windowToken
            if (windowToken != null) {
                return inputManager.hideSoftInputFromWindow(windowToken, 0)
            }
        }
    }
    return false
}

fun showKeyboard(editText: EditText) {
    val imm = editText.context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    imm.hideSoftInputFromWindow(editText.windowToken, 0)
    imm.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0)
    editText.requestFocus()
}

我的解决方案：

用活动构造它（视图是可选的），使用处理程序发布它（有一些延迟，例如100ms更好）。直接调用输入管理器有时不起作用。只有在工作时才能获得“活动”。我认为这很正常。

如果您可以在通话时获取根视图组或编辑视图，只需发送它即可获得更好的结果。

public class CloseSoftKeyboardRunnable implements Runnable
{
    Activity activity;
    View view;  // for dialog will occur context getcurrentfocus == null. send a rootview to find currentfocus.

    public CloseSoftKeyboardRunnable(Activity activity, View view)
    {
        this.activity = activity;
        this.view = view;
    }

    public CloseSoftKeyboardRunnable(Activity activity)
    {
        this.activity = activity;
    }
    @Override
    public void run() {
        if (!activity.isFinishing())
        {
            InputMethodManager imm = (InputMethodManager)activity.getSystemService(Context.INPUT_METHOD_SERVICE);

            if (view == null) {
                view = activity.getCurrentFocus();
            }
            else
            {
                try {
                    view = ((ViewGroup)view).getFocusedChild();
                }
                catch ( Exception e) {}
            }

            Window window =  activity.getWindow();
            
            if (window != null)
            {
                if (view == null) {
                    try {
                        view = window.getDecorView();
                        view = ((ViewGroup)view).getFocusedChild();
                    }
                    catch ( Exception e) {}
                }

                if (view == null) {
                    view = window.getDecorView();
                }

                if (view != null) {
                    if (view instanceof EditText)
                    {
                        EditText edittext = ((EditText) view);
                        edittext.setText(edittext.getText().toString()); // reset edit text bug on some keyboards bug
                        edittext.clearFocus();
                    }

                    imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
                }
                window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
            }
        }
    }
}

对于科特林爱好者。我创建了两个扩展函数。为了隐藏键盘的乐趣，您可以将edittext的实例作为视图传递。

fun Context.hideKeyboard(view: View) {
    (getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager)?.apply {
        hideSoftInputFromWindow(view.windowToken, 0)
    }
}

fun Context.showKeyboard() {
    (getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager)?.apply {
        toggleSoftInput(InputMethodManager.SHOW_FORCED, InputMethodManager.HIDE_IMPLICIT_ONLY)
    }
}

对于那些寻找喷气背包的人来说，写下答案。

val keyboardController = LocalSoftwareKeyboardController.current

//for showing the keyboard
keyboardController?.show()
//for hiding the keyboard
keyboardController?.hide()