详解Android 8.1.0 Service 中 弹出 Dialog的方法

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/><!--这行代码必须存在，否则点击不了系统设置中的按钮-->  <uses-permission android:name="android.permission.SYSTEM_OVERLAY_WINDOW" />

 private void checkMyPermission() {    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {      if (!Settings.canDrawOverlays(this)) {        Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,            Uri.parse("package:" + getPackageName()));        startActivityForResult(intent, 1);      }    }  }   @Override  protected void onActivityResult(int requestCode, int resultCode, Intent data) {    if (requestCode == 1) {      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {        if (Settings.canDrawOverlays(this)) {          Toast.makeText(this, "授权成功", Toast.LENGTH_SHORT).show();        }else {          // SYSTEM_ALERT_WINDOW permission not granted...          Toast.makeText(this, "未被授予权限，相关功能不可用", Toast.LENGTH_SHORT).show();        }      }    }  }

//在 Service 中创建全局变量 mHandler  private Handler mHandler;//在 Service 生命周期方法 onCreate() 中初始化 mHandler  mHandler = new Handler(Looper.getMainLooper());//在子线程中想要 Toast 的地方添加如下  mHandler.post(new Runnable() {          @Override          public void run() {            //show dialog            justShowDialog();          }        });   private void justShowDialog() {    AlertDialog.Builder builder = new AlertDialog.Builder(getApplicationContext())        .setIcon(android.R.drawable.ic_dialog_info)        .setTitle("service中弹出Dialog了")        .setMessage("是否关闭dialog？")        .setPositiveButton("确定",            new DialogInterface.OnClickListener() {              public void onClick(DialogInterface dialog,                        int whichButton) {              }            })        .setNegativeButton("取消",            new DialogInterface.OnClickListener() {              public void onClick(DialogInterface dialog,                        int whichButton) {              }            });    //下面这行代码放到子线程中会 Can't create handler inside thread that has not called Looper.prepare()    AlertDialog dialog = builder.create();    //设置点击其他地方不可取消此 Dialog    dialog.setCancelable(false);    dialog.setCanceledOnTouchOutside(false);    //8.0系统加强后台管理，禁止在其他应用和窗口弹提醒弹窗，如果要弹，必须使用TYPE_APPLICATION_OVERLAY，否则弹不出    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {      dialog.getWindow().setType((WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY));    }else {      dialog.getWindow().setType((WindowManager.LayoutParams.TYPE_SYSTEM_ALERT));    }    dialog.show();  }