Android 监听软键盘的高度并解决其覆盖输入框的问题

class KeyboardStatusWatcher(
    private val activity: FragmentActivity,
    private val lifecycleOwner: LifecycleOwner,
    private val listener: (isKeyboardShowed: Boolean, keyboardHeight: Int) -> Unit
) : PopupWindow(activity), ViewTreeObserver.OnGlobalLayoutListener {

    private val rootView by lazy { activity.window.decorView.rootView }

    private val TAG = "Keyboard-Tag"

    /**
     * 可见区域高度
     */
    private var visibleHeight = 0

    /**
     * 软键盘是否显示
     */
    var isKeyboardShowed = false
        private set

    /**
     * 最近一次弹出的软键盘高度
     */
    var keyboardHeight = 0
        private set

    /**
     * PopupWindow 布局
     */
    private val popupView by lazy {
        FrameLayout(activity).also {
            it.layoutParams = FrameLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.MATCH_PARENT
            )
            //监听布局大小变化
            it.viewTreeObserver.addOnGlobalLayoutListener(this)
        }
    }

    init {
        //初始化 PopupWindow
        contentView = popupView
        //软键盘弹出时，PopupWindow 要调整大小
        softInputMode =
            WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE or
                WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE
        inputMethodMode = INPUT_METHOD_NEEDED
        //宽度设为0，避免遮挡界面
        width = 0
        height = ViewGroup.LayoutParams.MATCH_PARENT
        setBackgroundDrawable(ColorDrawable(0))
        rootView.post { showAtLocation(rootView, Gravity.NO_GRAVITY, 0, 0) }

        //activity 销毁时或者 Fragment onDestroyView 时必须关闭 popupWindow ，避免内存泄漏
        lifecycleOwner.lifecycle.addObserver(object : DefaultLifecycleObserver {
            override fun onDestroy(owner: LifecycleOwner) {
                super.onDestroy(owner)
                dismiss()
            }
        })
    }

    /**
     * 监听布局大小变化
     */
    override fun onGlobalLayout() {
        val rect = Rect()
        //获取当前可见区域
        popupView.getWindowVisibleDisplayFrame(rect)
        if (visibleHeight == (rect.bottom - rect.top)) {
            //可见区域高度不变时不必执行下面代码，避免重复监听
            return
        } else {
            visibleHeight = (rect.bottom - rect.top)
        }
        //粗略计算高度的变化值，后面会根据状态栏和导航栏修正
        val heightDiff = rootView.height - visibleHeight
        //这里取了一个大概值，当窗口高度变化值超过屏幕的 1/3 时，视为软键盘弹出
        if (heightDiff > activity.screenHeight / 3) {
            isKeyboardShowed = true
            //非全屏时减去状态栏高度
            keyboardHeight =
                if (activity.isFullScreen) heightDiff else heightDiff - activity.statusBarHeight
            //导航栏显示时减去其高度，但横屏时导航栏在侧边，故不必扣除高度
            if (activity.hasNavBar && activity.isNavBarShowed && activity.isPortrait) {
                keyboardHeight -= activity.navBarHeight
            }
        } else {
            //软键盘隐藏时键盘高度为0
            isKeyboardShowed = false
            keyboardHeight = 0
        }
        listener.invoke(isKeyboardShowed, keyboardHeight)
    }
}

<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/clRoot"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/watermelon"
    tools:context=".MainActivity">

    <View
        android:id="@+id/vKeyboardBg"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:background="@android:color/white"
        app:layout_constraintBottom_toBottomOf="parent" />

    <androidx.appcompat.widget.AppCompatEditText
        android:imeOptions="flagNoExtractUi"
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginHorizontal="15dp"
        android:layout_marginVertical="8dp"
        android:background="@drawable/shape_edit_bg"
        android:hint="请输入"
        android:paddingHorizontal="10dp"
        app:layout_constraintBottom_toBottomOf="@id/vEditBg"
        app:layout_constraintTop_toTopOf="@id/vEditBg" />

</androidx.constraintlayout.widget.ConstraintLayout>

        KeyboardStatusWatcher(this,this) { isKeyboardShowed: Boolean, keyboardHeight: Int ->
            vKeyboardBg.updateLayoutParams<ConstraintLayout.LayoutParams> {
                bottomMargin = keyboardHeight
            }
            Log.d("Tag", "isShowed = $isKeyboardShowed,keyboardHeight = $keyboardHeight")
        }
    }