WebView加载不出来，显示空白页面

现象描述：webview加载H5链接是https，而h5中是图片地址拼接，造成加载不出来，显示空白页面。
log日志：
chromium: [INFO:CONSOLE(0)] "Mixed Content: The page at 'https://iot.onehaier.com/v2/cms/advert.detail.h5?advertId=201612141722070002' was loaded over HTTPS, but requested an insecure image 'http://onehaiercms.oss-cn-qingdao.aliyuncs.com/2016/12/14/17-21-340871526087485.jpg'. This request has been blocked; the content must be served over HTTPS., source: https://iot.onehaier.com/v2/cms/advert.detail.h5?advertId=201612141722070002 (0)

原因：H5链接是：https，而里边图片地址是：http；
Android webview 从Lollipop(5.0)开始webview默认不允许混合模式，https当中不能加载http资源，需要设置开启。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
settings.setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW);
}