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);
  }
}

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
                    }
            }
        }
    });
}

哇，安卓极客们有好消息了。是时候向旧的方式说再见了。 首先我将添加官方发布说明来阅读和了解更多关于这些方法/类，然后我们将看到这些神奇的方法/类

注意:在这些类/方法发布之前，不要将它们添加到你的发布应用中

如何检查键盘可见性

val insets = ViewCompat.getRootWindowInsets(view)
val isKeyboardVisible = insets.isVisible(Type.ime())

其他用途很少

如何获取键盘的高度

val insets = ViewCompat.getRootWindowInsets(view)
val keyboardHeight = insets.getInsets(Type.ime()).bottom

如何显示/隐藏键盘

val controller = view.windowInsetsController

// Show the keyboard
controller.show(Type.ime())

// Hide the keyboard
controller.hide(Type.ime())

注意:WindowInsetsController是在API-30中添加的，所以要等到向后兼容类不可用。

如何听键盘隐藏/显示事件

ViewCompat.setOnApplyWindowInsetsListener(view) { v, insets ->
    val isKeyboardVisible = insets.isVisible(Type.ime())
    if (isKeyboardVisible) {
        // Do it when keyboard is being shown
    } else {
        // Do it when keyboard is hidden
    }

    // Return the insets to keep going down this event to the view hierarchy
    insets
}

参考@TacB0sS的回答，我在Kotlin中开发了一个类。希望这对你有所帮助。如果需要改进，请告诉我。

class KeyboardVisibilityObserver(val layRootContainer: View?, val keyboardVisibilityListener: KeyboardVisibilityListener?) {
    var isKeyboardOpen = false
        private set

    private var keyBoardObserver = object : ViewTreeObserver.OnGlobalLayoutListener {

        private val DefaultKeyboardDP = 100

        // Lollipop includes button bar in the root. Add height of button bar (48dp) to maxDiff
        private val EstimatedKeyboardDP = DefaultKeyboardDP + if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) 48 else 0

        private val r = Rect()

        override fun onGlobalLayout() {
            if (layRootContainer != null) {
                // Convert the dp to pixels.
                val estimatedKeyboardHeight = TypedValue
                        .applyDimension(TypedValue.COMPLEX_UNIT_DIP, EstimatedKeyboardDP.toFloat(), layRootContainer.resources.displayMetrics).toInt()

                // Conclude whether the keyboard is shown or not.
                layRootContainer.getWindowVisibleDisplayFrame(r)
                val heightDiff = layRootContainer.rootView.height - (r.bottom - r.top)
                val isShown = heightDiff >= estimatedKeyboardHeight

                if (isShown == isKeyboardOpen) {
                    //  Log.d("Keyboard state", "Ignoring global layout change...");
                    return
                }

                isKeyboardOpen = isShown

                keyboardVisibilityListener?.onKeyboardVisibilityChanged(isKeyboardOpen)
            }
        }
    }

    init {
        layRootContainer?.viewTreeObserver?.addOnGlobalLayoutListener(keyBoardObserver)
    }

    // call this in onDestroy
    fun removeObserver(){
        layRootContainer?.viewTreeObserver?.removeOnGlobalLayoutListener(keyBoardObserver)
    }

    interface KeyboardVisibilityListener {
        fun onKeyboardVisibilityChanged(isKeyboardOpen: Boolean)
    }
}

Reuben Scratton的新答案(计算HeightDiff int HeightDiff = activityRootView.getRootView().getHeight() - activityRootView.getHeight();)如果您设置半透明状态栏模式，将无法在活动中工作。

如果你使用半透明状态栏，activityRootView.getHeight()将永远不会改变软键盘是否可见。它将始终返回活动和状态栏的高度。

例如，Nexus 4, Android 5.0.1，将Android:windowTranslucentStatus设置为true，它将永远返回1184，即使ime已经打开。如果你设置android:windowTranslucentStatus为false，它将正确返回高度，如果ime不可见，它将返回1134(不包括状态栏)。关闭ime，它可能会返回5xx(取决于ime的高度)

我不知道这是否是一个bug，我已经尝试了4.4.4和5.0.1，结果是一样的。

所以，到目前为止，第二个最被认可的答案，Kachi的解决方案将是最安全的方法来计算ime的高度。以下是一份复印件:

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.bottom - r.top);
if (heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
    ... do something here
    }
 }
}); 

这个解决方案可能会重新打开键盘，但它是有效的。

InputMethodManager inputManager = ( (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE) );

private boolean isKeyboardShowing() {

    boolean isKeyboardShowing = inputManager.hideSoftInputFromWindow(irrelevantView.getWindowToken(), 0);
    if (isKeyboardShowing) {
        inputManager.showSoftInput(this.getCurrentFocus(), 0);
    }
    return isKeyboardShowing;
}