WebView在Android 7.0 显示白屏

源码在我的这篇博客里面

http://blog.csdn.net/zhaiguoai/article/details/78608842

在android 4.4-6.0运行时无问题，但是一到7.0以上就是白屏

在度娘和谷哥搜了，解决方法无外乎这两种

http://blog.csdn.net/qwe0754444/article/details/64918868

http://www.jianshu.com/p/07b781795b78

但是我都试过了，没有用，请哪位大神帮帮小弟，谢谢

http://blog.csdn.net/qq_34584049/article/details/78280815

找到原因了，在获取IMEI和pingUrl上

         TelephonyManager tm = (TelephonyManager) this.getSystemService(TELEPHONY_SERVICE);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        assert tm != null;
        @SuppressLint("HardwareIds") String imei = tm.getDeviceId();

删除它不可以正常运行，那么再问一下，请问怎么在android 7.0以上不用上面方法获取IMEI呢?