Reuben Scratton和Kachi提供的解决方案似乎依赖于设备的像素密度，如果你有一个高密度的设备，即使按下键盘，高度差也可能超过100。围绕这一点的工作将是看到初始高度差(键盘向下)，然后与当前的差异进行比较。

boolean isOpened = false;
int firstHeightDiff = -1;

public void setListenerToRootView(){
    final View activityRootView = getActivity().getWindow().getDecorView().findViewById(android.R.id.content);
    Rect r = new Rect();
    activityRootView.getWindowVisibleDisplayFrame(r);
    firstHeightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
    activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            if (isAdded()) {
                Rect r = new Rect();
                activityRootView.getWindowVisibleDisplayFrame(r);
                int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
                isOpened = heightDiff>firstHeightDiff+100;
                if (isAdded())
                    if(isOpened) {
                        //TODO stuff for when it is up
                    } else {
                        //TODO stuf for when it is down
                    }
            }
        }
    });
}

有一种直接的方法可以找出答案。而且，它不需要任何布局更改。 所以，它也可以在沉浸式全屏模式下工作。 诀窍在于，您尝试隐藏或显示软键盘，并捕获尝试的结果。 没有恐慌，这并不真正显示或隐藏键盘。我们只要求状态。 为了保持最新，您可以简单地重复操作，例如，每200毫秒，使用处理器。 您可以在这里找到一个实现:https://stackoverflow.com/a/27567074/2525452

我认为这个方法将帮助你找出是键盘是可见的或不。

 public Boolean isSoftKeyBoardVisible(){
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);

    if (imm.isAcceptingText()) {
        Log.d(TAG,"Software Keyboard was shown");
        return true;
    } else {
        Log.d(TAG,"Software Keyboard was not shown");
        return false;
    }

}

除了正确的答案，我必须在onCreateView的末尾添加这个，当使用一个片段内的webview。

getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);

可能是因为我在一个片段中运行Webview，或者可能是API 30上的一个新行为，我的问题是，即使显示键盘，片段的高度也从未改变。

所以对于Fragment，整个代码应该是

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = super.onCreateView(inflater, container, savedInstanceState);
    //mWebView.postUrl("https://www.google.com/");
    final View activityRootView = view;
    layoutListener = new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            Rect r = new Rect();
            //r will be populated with the coordinates of your view that area still visible.
            activityRootView.getWindowVisibleDisplayFrame(r);
            // This variable was created only for Debug purposes and 
            // to see the height change when clicking on a field inside mWebView
            int screenHeight = activityRootView.getRootView().getHeight();
            Log.d("onGlobalLayout", "rect: " + r.toString());
            Log.d("onGlobalLayout", "screenHeight: " + screenHeight);

            //The difference on the heights from bottom to top and on the root height
            int heightDiff = screenHeight - (r.bottom - r.top);
            Log.d("onGlobalLayout", "heightDiff: " + heightDiff);

            //I suggest to put 250 on resources to have better order
            float dpx = dpToPx(getActivity(), 250);

            if (previousHeightDiff != heightDiff) {
                if (heightDiff > dpx) {
                    isSoftKeyboardPresent = true;
                } else {
                    isSoftKeyboardPresent = false;
                }
                previousHeightDiff = heightDiff;
            }
        }
    };
    activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(layoutListener);
    getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
    return view;
}

private static float dpToPx(Context context, float valueInDp) {
    DisplayMetrics metrics = context.getResources().getDisplayMetrics();
    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, valueInDp, metrics);
}

也许这对你有帮助:

InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);

在了解了不同分辨率的一些问题后，我决定使用相对大小。正如我所注意到的，可见状态和隐藏状态之间的差异约为30%。所以我决定用0.3代替128 PX。

我添加了这个类监听器来通知任何变化。

这是我的版本

import android.app.*;
import android.graphics.*;
import android.view.*;

public class SoftKeyboardState {
  public static final int HIDDEN = 0, VISIBLE = 1;
  private OnKeyboardStateChangedListener listener;
  private View decorView;

  public SoftKeyboardState(Activity activity) {
    this.decorView = activity.findViewById(android.R.id.content);
    initKeyboardListener();
  }

  private void initKeyboardListener() {
    decorView.getViewTreeObserver().addOnGlobalLayoutListener(
      new ViewTreeObserver.OnGlobalLayoutListener(){
        private final Rect windowVisibleDisplayFrame = new Rect();
        private int lastVisibleDecorViewHeight;

        @Override
        public void onGlobalLayout() {
          decorView.getWindowVisibleDisplayFrame(windowVisibleDisplayFrame);
          final int visibleDecorViewHeight = windowVisibleDisplayFrame.height();

          if (lastVisibleDecorViewHeight != 0) {
            if ((lastVisibleDecorViewHeight > visibleDecorViewHeight) && (lastVisibleDecorViewHeight / visibleDecorViewHeight >= 0.3f)) {
              // visible
              if (listener != null)listener.onKeyboardStateChanged(VISIBLE);
            } else if ((lastVisibleDecorViewHeight < visibleDecorViewHeight) && (visibleDecorViewHeight / lastVisibleDecorViewHeight >= 0.3f)) {
              // hidden
              if (listener != null)listener.onKeyboardStateChanged(HIDDEN);
            }
          }
          lastVisibleDecorViewHeight = visibleDecorViewHeight;
        }
      });
  }

  public void setOnKeyboardStateChangedListener(OnKeyboardStateChangedListener listener) {
    this.listener = listener;
  }

  public interface OnKeyboardStateChangedListener {
    public void onKeyboardStateChanged(int state);
  }
}