[移动开发]Kotlin添加窗口报错

Process: 包名, PID: 27541
android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
        at android.view.ViewRootImpl.setView(ViewRootImpl.java:980)
        at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:398)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:96)

报错描述： 通过在当前Service服务中动态wm.addView(view, lp)添加一个window窗口。执行时报错，错误信息如上面代码片。该服务Service启动于MainAcitivity并作为前台服务一直处于保活状态。

创建窗口代码

import android.content.Context
import android.graphics.PixelFormat
import android.os.Build
import android.util.Log
import android.view.Gravity
import android.view.View
import android.view.WindowManager

/**
 * WindowCreated.kt 添加窗口类
 */
object WindowCreated {
    private lateinit var context: Context
    private lateinit var wm: WindowManager
    private lateinit var lp: WindowManager.LayoutParams

    fun initWindow(context: Context) {
        this.context = context
        this.wm = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
        lp = createLayoutParams()
    }
    // 创建布局属性
    fun createLayoutParams(): WindowManager.LayoutParams {
        val lp = WindowManager.LayoutParams()
        lp.apply {
            this.width = WindowManager.LayoutParams.MATCH_PARENT
            this.height = WindowManager.LayoutParams.MATCH_PARENT
            gravity = Gravity.CENTER
            format = PixelFormat.TRANSLUCENT
            flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL or
                    WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE or
                    WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON or
                    WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS
            // >=   8.0
            type = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
                WindowManager.LayoutParams.TYPE_ACCESSIBILITY_OVERLAY
            else
                WindowManager.LayoutParams.TYPE_PHONE

        }

        return lp
    }

    // 获取视图控件
    fun getView(layoutId: Int): View {
        return View.inflate(context, layoutId, null)
    }

    // 显示窗口
    fun  showWindowView(view: View) {
        Log.e("=====com.wensi显示窗口=====", view.toString())
        if (view.parent == null) {
            wm.addView(view, lp)
        }
    }

    fun  showWindowView(view: View, lp: WindowManager.LayoutParams) {
        if (view.parent == null) {
            wm.addView(view, lp)
        }
    }
    // 隐藏窗口
    fun  hideWindowView(view: View) {
        if (view.parent == null) {
            // 不等于空，说明正在显示
            wm.removeView(view)
        }
    }
    // 更新视图
    fun updateWindowView(view: View, lp: WindowManager.LayoutParams) {
        wm.updateViewLayout(view, lp)
    }
}

之后在Service服务方法override fun onCreate()中初始化窗口及布局

WindowCreated.initWindowHelper(this) // 初始化窗口
fullWindowView = WindowCreated.getView(R.layout.layout_window_item)

然后通过用户触发事件激活并添加窗口
WindowCreated.showWindowView(fullWindowView)
但执行后报错。后来经过逐步排查，窗口权限已添加且申请

	// 申请权限
    protected fun requestWindowPermission(packageName: String) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { // >= 23  6.0
            startActivityForResult(
                Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION, Uri.parse("package:$packageName")),
                codeWindowPermission) // codeWindowPermission = 1000
        }
    }

排查方向不对： 业务逻辑代码也无问题，即不存在popWindow初始化显示窗口过早问题。
排查方向不对： 为避免出现类似new AlertDialog.Builder(context)一样的问题，尝试将context指向Activity。

后经过查看源码即第37行布局属性发现了问题：(不小心赋值变量错误导致)
应用必须使用名为TYPE_APPLICATION_OVERLAY的新窗口, 而不是TYPE_ACCESSIBILITY_OVERLAY。