我推荐使用一个LifecycleObserver，它是Android Jetpack中使用生命周期感知组件处理生命周期的一部分。

当片段/活动出现时，我想打开和关闭键盘。首先，为EditText定义两个扩展函数。你可以把它们放在项目的任何地方:

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

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

然后定义一个LifecycleObserver，当Activity/Fragment到达onResume()或onPause时打开和关闭键盘:

class EditTextKeyboardLifecycleObserver(private val editText: WeakReference<EditText>) :
    LifecycleObserver {

    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    fun openKeyboard() {
        editText.get()?.postDelayed({ editText.get()?.showKeyboard() }, 100)
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
    fun closeKeyboard() {
        editText.get()?.hideKeyboard()
    }
}

然后将下面的行添加到您的任何片段/活动中，您可以在任何时候重用LifecycleObserver。例如，对于片段:

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

    // inflate the Fragment layout

    lifecycle.addObserver(EditTextKeyboardLifecycleObserver(WeakReference(myEditText)))

    // do other stuff and return the view

}

这些答案我一个都找不到。我的解决方案是将它们结合起来:

InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, InputMethodManager.HIDE_IMPLICIT_ONLY);
editText.requestFocus();
imm.showSoftInput(editText, InputMethodManager.SHOW_FORCED);

我不确定为什么这对我来说是必需的——根据文档，似乎这两种方法都应该单独起作用。

这对我很有效， 多亏了ungalcrys

显示键盘:

editText = (EditText)findViewById(R.id.myTextViewId);
editText.requestFocus();
InputMethodManager imm = (InputMethodManager)getSystemService(this.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED,InputMethodManager.HIDE_IMPLICIT_ONLY);

隐藏键盘:

InputMethodManager imm = (InputMethodManager) getSystemService(this.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(editText.getWindowToken(), 0);

我只用了一行代码

firstInputField.setNextFocusDownId(R.id.id_of_next_targeted_text_field);

下面是如何显示和隐藏软键盘的kotlin扩展:

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)
}

然后你可以这样做:

editText.showKeyboard()
// OR
editText.hideKeyboard()

这里是KeyboardHelper类，用于隐藏和显示键盘

import android.content.Context;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;

/**
 * Created by khanhamza on 06-Mar-17.
 */

public class KeyboardHelper {
public static void hideSoftKeyboard(final Context context, final View view) {
    if (context == null) {
        return;
    }
    view.requestFocus();
    view.postDelayed(new Runnable() {
        @Override
        public void run() {
            InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
assert imm != null;
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
}, 1000);
}

public static void hideSoftKeyboard(final Context context, final EditText editText) {
    editText.requestFocus();
    editText.postDelayed(new Runnable() {
        @Override
        public void run() {
            InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
assert imm != null;
imm.hideSoftInputFromWindow(editText.getWindowToken(), 0);
}
}, 1000);
}


public static void openSoftKeyboard(final Context context, final EditText editText) {
    editText.requestFocus();
    editText.postDelayed(new Runnable() {
        @Override
        public void run() {
            InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
assert imm != null;
imm.showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT);
}
}, 1000);
}
}