非常容易

1. 把id放在根视图上

rootView只是一个视图指向我的根视图在这种情况下，一个相对布局:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/addresses_confirm_root_view"
                android:background="@color/WHITE_CLR">

2. 在Activity中初始化根视图:

RelativeLayout rootView = (RelativeLayout) findViewById(R.id.addresses_confirm_root_view);

3.使用getViewTreeObserver()检测键盘是否打开或关闭

    rootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                int heightDiff = rootView.getRootView().getHeight() - rootView.getHeight();
                
                if (heightDiff > 100) { // Value should be less than keyboard's height 
                    Log.e("MyActivity", "keyboard opened");
                } else { 
                    Log.e("MyActivity", "keyboard closed");
                }
            }
        });

这应该工作，如果你需要检查键盘状态:

fun Activity.isKeyboardOpened(): Boolean {
    val r = Rect()

    val activityRoot = getActivityRoot()
    val visibleThreshold = dip(UiUtils.KEYBOARD_VISIBLE_THRESHOLD_DP)

    activityRoot.getWindowVisibleDisplayFrame(r)

    val heightDiff = activityRoot.rootView.height - r.height()

    return heightDiff > visibleThreshold;
}

fun Activity.getActivityRoot(): View {
    return (findViewById<ViewGroup>(android.R.id.content)).getChildAt(0);
}

UiUtils的地方。KEYBOARD_VISIBLE_THRESHOLD_DP = 100, dip()是一个anko函数，转换dpToPx:

fun dip(value: Int): Int {
    return (value * Resources.getSystem().displayMetrics.density).toInt()
}

所以，在花了很长一段时间摆弄accesessibilityservices、窗口嵌入、屏幕高度检测等之后，我想我找到了一种方法来做到这一点。

免责声明:它在Android中使用了一个隐藏的方法，这意味着它可能不一致。然而，在我的测试中，它似乎有效。

该方法是InputMethodManager#getInputMethodWindowVisibleHeight()，它自Lollipop(5.0)以来就存在了。

调用它将返回当前键盘的高度(以像素为单位)。理论上，键盘不应该是0像素高，所以我做了一个简单的高度检查(在Kotlin中):

val imm by lazy { context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager }
if (imm.inputMethodWindowVisibleHeight > 0) {
    //keyboard is shown
else {
    //keyboard is hidden
}

当我调用隐藏方法时，我使用Android隐藏API来避免反射(我为我开发的应用程序做了很多，这些应用程序主要是hack /tuner应用程序)，但这应该也是可能的反射:

val imm by lazy { context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager }
val windowHeightMethod = InputMethodManager::class.java.getMethod("getInputMethodWindowVisibleHeight")
val height = windowHeightMethod.invoke(imm) as Int
//use the height val in your logic

There is a direct method to find this out. And, it does not require the layout changes. So it works in immersive fullscreen mode, too. But, unfortunately, it does not work on all devices. So you have to test it with your device(s). The trick is that you try to hide or show the soft keyboard and capture the result of that try. If it works correct then the keyboard is not really shown or hidden. We just ask for the state. To stay up-to-date, you simply repeat this operation, e.g. every 200 milliseconds, using a Handler. The implementation below does just a single check. If you do multiple checks, then you should enable all the (_keyboardVisible) tests.

public interface OnKeyboardShowHide
{
    void    onShowKeyboard( Object param );
    void    onHideKeyboard( Object param );
}

private static Handler      _keyboardHandler    = new Handler();
private boolean             _keyboardVisible    = false;
private OnKeyboardShowHide  _keyboardCallback;
private Object              _keyboardCallbackParam;

public void start( OnKeyboardShowHide callback, Object callbackParam )
{
    _keyboardCallback      = callback;
    _keyboardCallbackParam = callbackParam;
    //
    View view = getCurrentFocus();
    if (view != null)
    {
        InputMethodManager imm = (InputMethodManager) getSystemService( Activity.INPUT_METHOD_SERVICE );
        imm.hideSoftInputFromWindow( view.getWindowToken(), InputMethodManager.HIDE_IMPLICIT_ONLY, _keyboardResultReceiver );
        imm.showSoftInput( view, InputMethodManager.SHOW_IMPLICIT, _keyboardResultReceiver );
    }
    else // if (_keyboardVisible)
    {
        _keyboardVisible = false;
        _keyboardCallback.onHideKeyboard( _keyboardCallbackParam );
    }
}

private ResultReceiver      _keyboardResultReceiver = new ResultReceiver( _keyboardHandler )
{
    @Override
    protected void onReceiveResult( int resultCode, Bundle resultData )
    {
        switch (resultCode)
        {
            case InputMethodManager.RESULT_SHOWN :
            case InputMethodManager.RESULT_UNCHANGED_SHOWN :
                // if (!_keyboardVisible)
                {
                    _keyboardVisible = true;
                    _keyboardCallback.onShowKeyboard( _keyboardCallbackParam );
                }
                break;
            case InputMethodManager.RESULT_HIDDEN :
            case InputMethodManager.RESULT_UNCHANGED_HIDDEN :
                // if (_keyboardVisible)
                {
                    _keyboardVisible = false;
                    _keyboardCallback.onHideKeyboard( _keyboardCallbackParam );
                }
                break;
        }
    }
};

这对我很有用。也许这对于所有版本来说都是最好的方法。

这将是有效的，使键盘可见性的属性，并观察这个变化延迟，因为onGlobalLayout方法调用多次。此外，检查设备旋转和windowSoftInputMode是否为adjustNothing也很好。

boolean isKeyboardShowing = false;
void onKeyboardVisibilityChanged(boolean opened) {
    print("keyboard " + opened);
}

// ContentView is the root view of the layout of this activity/fragment    
contentView.getViewTreeObserver().addOnGlobalLayoutListener(
    new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {

        Rect r = new Rect();
        contentView.getWindowVisibleDisplayFrame(r);
        int screenHeight = contentView.getRootView().getHeight();

        // r.bottom is the position above soft keypad or device button.
        // if keypad is shown, the r.bottom is smaller than that before.
        int keypadHeight = screenHeight - r.bottom;

        Log.d(TAG, "keypadHeight = " + keypadHeight);

        if (keypadHeight > screenHeight * 0.15) { // 0.15 ratio is perhaps enough to determine keypad height.
            // keyboard is opened
            if (!isKeyboardShowing) {
                isKeyboardShowing = true
                onKeyboardVisibilityChanged(true)
            }
        }
        else {
            // keyboard is closed
            if (isKeyboardShowing) {
                isKeyboardShowing = false
                onKeyboardVisibilityChanged(false)
            }
        }
    }
});

它使用活动的adjustNothing标志和使用生命周期事件。还有Kotlin:

/**
 * This class uses a PopupWindow to calculate the window height when the floating keyboard is opened and closed
 *
 * @param activity The parent activity
 *  The root activity that uses this KeyboardManager
 */
class KeyboardManager(private val activity: AppCompatActivity) : PopupWindow(activity), LifecycleObserver {

    private var observerList = mutableListOf<((keyboardTop: Int) -> Unit)>()

    /** The last value of keyboardTop */
    private var keyboardTop: Int = 0

    /** The view that is used to calculate the keyboard top  */
    private val popupView: View?

    /** The parent view  */
    private var parentView: View

    var isKeyboardShown = false
        private set

    /**
     * Create transparent view which will be stretched over to the full screen
     */
    private fun createFullScreenView(): View {
        val view = LinearLayout(activity)
        view.layoutParams = LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT)
        view.background = ColorDrawable(Color.TRANSPARENT)
        return view
    }

    init {
        this.popupView = createFullScreenView()
        contentView = popupView

        softInputMode = LayoutParams.SOFT_INPUT_ADJUST_RESIZE or LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE
        inputMethodMode = INPUT_METHOD_NEEDED

        parentView = activity.findViewById(android.R.id.content)

        width = 0
        height = LayoutParams.MATCH_PARENT

        popupView.viewTreeObserver.addOnGlobalLayoutListener {
            val rect = Rect()
            popupView.getWindowVisibleDisplayFrame(rect)

            val keyboardTop = rect.bottom
            if (this.keyboardTop != keyboardTop) {
                isKeyboardShown = keyboardTop < this.keyboardTop
                this.keyboardTop = keyboardTop
                observerList.forEach { it(keyboardTop) }
            }
        }
        activity.lifecycle.addObserver(this)
    }

    /**
     * This must be called after the onResume of the Activity or inside view.post { } .
     * PopupWindows are not allowed to be registered before the onResume has finished
     * of the Activity
     */
    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    fun start() {
        parentView.post {
            if (!isShowing && parentView.windowToken != null) {
                setBackgroundDrawable(ColorDrawable(0))
                showAtLocation(parentView, Gravity.NO_GRAVITY, 0, 0)
            }
        }
    }

    /**
     * This manager will not be used anymore
     */
    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    fun close() {
        activity.lifecycle.removeObserver(this)
        observerList.clear()
        dismiss()
    }

    /**
     * Set the keyboard top observer. The observer will be notified when the keyboard top has changed.
     * For example when the keyboard is opened or closed
     *
     * @param observer The observer to be added to this provider
     */
    fun registerKeyboardTopObserver(observer: (keyboardTop: Int) -> Unit) {
        observerList.add(observer)
    }
}

有用的方法，保持视图始终高于键盘

fun KeyboardManager.updateBottomMarginIfKeyboardShown(
        view: View,
        activity: AppCompatActivity,
        // marginBottom of view when keyboard is hide
        marginBottomHideKeyboard: Int,
        // marginBottom of view when keybouard is shown
        marginBottomShowKeyboard: Int
) {
    registerKeyboardTopObserver { bottomKeyboard ->
        val bottomView = ViewUtils.getFullViewBounds(view).bottom
        val maxHeight = ScreenUtils.getFullScreenSize(activity.windowManager).y
        // Check that view is within the window size
        if (bottomView < maxHeight) {
            if (bottomKeyboard < bottomView) {
                ViewUtils.updateMargin(view, bottomMargin = bottomView - bottomKeyboard +
                        view.marginBottom + marginBottomShowKeyboard)
            } else ViewUtils.updateMargin(view, bottomMargin = marginBottomHideKeyboard)
        }
    }
}

在getFullViewBounds

fun getLocationOnScreen(view: View): Point {
    val location = IntArray(2)
    view.getLocationOnScreen(location)
    return Point(location[0], location[1])
}

fun getFullViewBounds(view: View): Rect {
     val location = getLocationOnScreen(view)
     return Rect(location.x, location.y, location.x + view.width,
            location.y + view.height)
 }

在getFullScreenSize

fun getFullScreenSize(wm: WindowManager? = null) =
            getScreenSize(wm) { getRealSize(it) }

private fun getScreenSize(wm: WindowManager? = null, block: Display.(Point) -> Unit): Point {
    val windowManager = wm ?: App.INSTANCE.getSystemService(Context.WINDOW_SERVICE)
            as WindowManager
    val point = Point()
    windowManager.defaultDisplay.block(point)
    return point
}

其中更新边距

fun updateMargin(
        view: View,
        leftMargin: Int? = null,
        topMargin: Int? = null,
        rightMargin: Int? = null,
        bottomMargin: Int? = null
) {
    val layoutParams = view.layoutParams as ViewGroup.MarginLayoutParams
    if (leftMargin != null) layoutParams.leftMargin = leftMargin
    if (topMargin != null) layoutParams.topMargin = topMargin
    if (rightMargin != null) layoutParams.rightMargin = rightMargin
    if (bottomMargin != null) layoutParams.bottomMargin = bottomMargin
    view.layoutParams = layoutParams
}