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);
}

一些改进，以避免在高密度设备上错误地检测软键盘的可见性:

Threshold of height difference should be defined as 128 dp, not 128 pixels. Refer to Google design doc about Metrics and Grid, 48 dp is comfortable size for touch object and 32 dp is minimum for buttons. Generic soft keyboard should include 4 rows of key buttons, so minimum keyboard height should be: 32 dp * 4 = 128 dp, that means threshold size should transfer to pixels by multiply device density. For xxxhdpi devices (density 4), the soft keyboard height threshold should be 128 * 4 = 512 pixels. Height difference between root view and its visible area: root view height - status bar height - visible frame height = root view bottom - visible frame bottom, since status bar height equal to the top of root view visible frame. private final String TAG = "TextEditor"; private TextView mTextEditor; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_editor); mTextEditor = (TextView) findViewById(R.id.text_editor); mTextEditor.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { isKeyboardShown(mTextEditor.getRootView()); } }); } private boolean isKeyboardShown(View rootView) { /* 128dp = 32dp * 4, minimum button height 32dp and generic 4 rows soft keyboard */ final int SOFT_KEYBOARD_HEIGHT_DP_THRESHOLD = 128; Rect r = new Rect(); rootView.getWindowVisibleDisplayFrame(r); DisplayMetrics dm = rootView.getResources().getDisplayMetrics(); /* heightDiff = rootView height - status bar height (r.top) - visible frame height (r.bottom - r.top) */ int heightDiff = rootView.getBottom() - r.bottom; /* Threshold size: dp to pixels, multiply with display density */ boolean isKeyboardShown = heightDiff > SOFT_KEYBOARD_HEIGHT_DP_THRESHOLD * dm.density; Log.d(TAG, "isKeyboardShown ? " + isKeyboardShown + ", heightDiff:" + heightDiff + ", density:" + dm.density + "root view height:" + rootView.getHeight() + ", rect:" + r); return isKeyboardShown; }

抱歉回答晚了，但我已经创建了一个小的帮助类来处理打开/关闭事件，通知侦听器和其他有用的东西，可能有人会发现它有帮助:

import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver;

import java.util.LinkedList;
import java.util.List;

public class SoftKeyboardStateWatcher implements ViewTreeObserver.OnGlobalLayoutListener {

    public interface SoftKeyboardStateListener {
        void onSoftKeyboardOpened(int keyboardHeightInPx);
        void onSoftKeyboardClosed();
    }

    private final List<SoftKeyboardStateListener> listeners = new LinkedList<SoftKeyboardStateListener>();
    private final View activityRootView;
    private int        lastSoftKeyboardHeightInPx;
    private boolean    isSoftKeyboardOpened;

    public SoftKeyboardStateWatcher(View activityRootView) {
        this(activityRootView, false);
    }

    public SoftKeyboardStateWatcher(View activityRootView, boolean isSoftKeyboardOpened) {
        this.activityRootView     = activityRootView;
        this.isSoftKeyboardOpened = isSoftKeyboardOpened;
        activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(this);
    }

    @Override
    public void onGlobalLayout() {
        final Rect r = new Rect();
        //r will be populated with the coordinates of your view that area still visible.
        activityRootView.getWindowVisibleDisplayFrame(r);

        final int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
        if (!isSoftKeyboardOpened && heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
            isSoftKeyboardOpened = true;
            notifyOnSoftKeyboardOpened(heightDiff);
        } else if (isSoftKeyboardOpened && heightDiff < 100) {
            isSoftKeyboardOpened = false;
            notifyOnSoftKeyboardClosed();
        }
    }

    public void setIsSoftKeyboardOpened(boolean isSoftKeyboardOpened) {
        this.isSoftKeyboardOpened = isSoftKeyboardOpened;
    }

    public boolean isSoftKeyboardOpened() {
        return isSoftKeyboardOpened;
    }

    /**
     * Default value is zero {@code 0}.
     *
     * @return last saved keyboard height in px
     */
    public int getLastSoftKeyboardHeightInPx() {
        return lastSoftKeyboardHeightInPx;
    }

    public void addSoftKeyboardStateListener(SoftKeyboardStateListener listener) {
        listeners.add(listener);
    }

    public void removeSoftKeyboardStateListener(SoftKeyboardStateListener listener) {
        listeners.remove(listener);
    }

    private void notifyOnSoftKeyboardOpened(int keyboardHeightInPx) {
        this.lastSoftKeyboardHeightInPx = keyboardHeightInPx;

        for (SoftKeyboardStateListener listener : listeners) {
            if (listener != null) {
                listener.onSoftKeyboardOpened(keyboardHeightInPx);
            }
        }
    }

    private void notifyOnSoftKeyboardClosed() {
        for (SoftKeyboardStateListener listener : listeners) {
            if (listener != null) {
                listener.onSoftKeyboardClosed();
            }
        }
    }
}

使用的例子:

final SoftKeyboardStateWatcher softKeyboardStateWatcher 
    = new SoftKeyboardStateWatcher(findViewById(R.id.activity_main_layout);

// Add listener
softKeyboardStateWatcher.addSoftKeyboardStateListener(...);
// then just handle callbacks

希望这能帮助到大家。

Reuben Scratton给出的新答案非常棒，而且非常有效，但它只在你将windowSoftInputMode设置为adjuststresize时才有效。如果你将它设置为adjustPan，使用他的代码片段仍然无法检测键盘是否可见。为了解决这个问题，我对上面的代码做了微小的修改。

final View activityRootView = findViewById(R.id.activityRoot);
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new 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);
   
    int heightDiff = activityRootView.getRootView().getHeight() - r.height();
    if (heightDiff > 0.25*activityRootView.getRootView().getHeight()) { // if more than 25% of the screen, its probably a keyboard...
        ... do something here
    }
 }
}); 

有一个隐藏的方法可以帮助这个，inputmethodmanager。getinputmethodwindowvisibleheight。但我不知道为什么要藏起来。

import android.content.Context
import android.os.Handler
import android.view.inputmethod.InputMethodManager

class SoftKeyboardStateWatcher(private val ctx: Context) {
  companion object {
    private const val DELAY = 10L
  }

  private val handler = Handler()
  private var isSoftKeyboardOpened: Boolean = false

  private val height: Int
    get() {
      val imm = ctx.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
      val method = imm.javaClass.getMethod("getInputMethodWindowVisibleHeight")
      method.isAccessible = true
      return method.invoke(imm) as Int
    }

  private val task: Runnable by lazy {
    Runnable {
      start()
      if (!isSoftKeyboardOpened && height > 0) {
        isSoftKeyboardOpened = true
        notifyOnSoftKeyboardOpened(height)
      } else if (isSoftKeyboardOpened && height == 0) {
        isSoftKeyboardOpened = false
        notifyOnSoftKeyboardClosed()
      }
    }
  }

  var listener: SoftKeyboardStateListener? = null

  interface SoftKeyboardStateListener {
    fun onSoftKeyboardOpened(keyboardHeightInPx: Int)
    fun onSoftKeyboardClosed()
  }

  fun start() {
    handler.postDelayed(task, DELAY)
  }

  fun stop() {
    handler.postDelayed({
      if (!isSoftKeyboardOpened) handler.removeCallbacks(task)
    }, DELAY * 10)
  }

  private fun notifyOnSoftKeyboardOpened(keyboardHeightInPx: Int) {
    listener?.onSoftKeyboardOpened(keyboardHeightInPx)
  }

  private fun notifyOnSoftKeyboardClosed() {
    listener?.onSoftKeyboardClosed()
  }
}

我的答案基本上与Kachi的答案相同，但我将它包装到一个很好的helper类中，以清理它在整个应用程序中的使用方式。

import android.app.Activity;
import android.app.Fragment;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;

/**
 * Detects Keyboard Status changes and fires events only once for each change
 */
public class KeyboardStatusDetector {
    KeyboardVisibilityListener visibilityListener;

    boolean keyboardVisible = false;

    public void registerFragment(Fragment f) {
        registerView(f.getView());
    }

    public void registerActivity(Activity a) {
        registerView(a.getWindow().getDecorView().findViewById(android.R.id.content));
    }

    public KeyboardStatusDetector registerView(final View v) {
        v.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                Rect r = new Rect();
                v.getWindowVisibleDisplayFrame(r);

                int heightDiff = v.getRootView().getHeight() - (r.bottom - r.top);
                if (heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
                    /** Check this variable to debounce layout events */
                    if(!keyboardVisible) {
                        keyboardVisible = true;
                        if(visibilityListener != null) visibilityListener.onVisibilityChanged(true);
                    }
                } else {
                    if(keyboardVisible) {
                        keyboardVisible = false;
                        if(visibilityListener != null) visibilityListener.onVisibilityChanged(false);
                    }
                }
            }
        });

        return this;
    }

    public KeyboardStatusDetector setVisibilityListener(KeyboardVisibilityListener listener) {
        visibilityListener = listener;
        return this;
    }

    public static interface KeyboardVisibilityListener {
        public void onVisibilityChanged(boolean keyboardVisible);
    }
}

你可以使用它来检测整个应用程序中的键盘变化，如下所示:

    new KeyboardStatusDetector()
            .registerFragment(fragment)  //register to a fragment 
            .registerActivity(activity)  //or register to an activity
            .registerView(view)          //or register to a view
            .setVisibilityListener(new KeyboardVisibilityListener() {
                @Override
                public void onVisibilityChanged(boolean keyboardVisible) {
                    if(keyboardVisible) {
                       //Do stuff for keyboard visible
                    }else {
                       //Do stuff for keyboard hidden
                    }
                }
            });

注意:只使用一个“寄存器”调用。它们都是一样的，只是为了方便