具体的报错内容如下

E/MainApplication.java: [(MainApplication.java:86)#uncaughtException]uncaught exception
                                                                          java.lang.NullPointerException: Attempt to read from field 'java.lang.String com.umeng.socialize.net.LinkCardResponse.url' on a null object reference
                                                                              at com.umeng.socialize.media.SinaShareContent.getWebpageObj(SinaShareContent.java:138)
                                                                              at com.umeng.socialize.media.SinaShareContent.getMessage(SinaShareContent.java:45)
                                                                              at com.umeng.socialize.handler.SinaSsoHandler.share(SinaSsoHandler.java:327)
                                                                              at com.umeng.socialize.controller.SocialRouter.share(SocialRouter.java:748)
                                                                              at com.umeng.socialize.UMShareAPI$4.doInBackground(UMShareAPI.java:203)
                                                                              at com.umeng.socialize.UMShareAPI$4.doInBackground(UMShareAPI.java:194)
                                                                              at com.umeng.socialize.common.QueuedWork$UMAsyncTask$1.run(QueuedWork.java:141)
                                                                              at java.lang.Thread.run(Thread.java:818)

代码中调用的地方大致如下:

new ShareAction(activity).withMedia(web)
                    .setPlatform(platform)
                    .setCallback(umShareListener)
                    .share();

经过分析，崩溃的线程和调用并非在同一个线程，此时try catch调用的地方来阻止崩溃是没用的。

最后，通过跟踪源码，发现最终调用分享的代码是SinaSsoHandler的share()函数,解决思路是自己创建一个SinaSsoHandler，通过反射注入到友盟的源码里面，替换掉原有的SinaSsoHandler，复写share()。

代码如下：

try {
            UMShareAPI umShareAPI = UMShareAPI.get(getContext());
            Field socialRouterField = umShareAPI.getClass().getDeclaredField("router");
            socialRouterField.setAccessible(true);
            Object socialRouterObj = socialRouterField.get(umShareAPI);

            Field platformHandlersHandlerField = SocialRouter.class.getDeclaredField("platformHandlers");
            platformHandlersHandlerField.setAccessible(true);
            Object platformHandlersHandlerObj = platformHandlersHandlerField.get(socialRouterObj);
            Map<SHARE_MEDIA, UMSSOHandler> platformHandlers = (Map<SHARE_MEDIA, UMSSOHandler>) platformHandlersHandlerObj;
            platformHandlers.put(SHARE_MEDIA.SINA, new SinaSsoHandler(){
                @Override
                public boolean share(ShareContent content, UMShareListener listener) {
                    try{
                        return super.share(content, listener);
                    }catch (Exception e){
                        e.printStackTrace();
                        TaskExecutors.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Toaster.show("分享失败");
                            }
                        });
                        return false;
                    }
                }
            });

            new ShareAction(activity).withMedia(web)
                    .setPlatform(platform)
                    .setCallback(umShareListener)
                    .share();
        }catch (Exception e){
            e.printStackTrace();
        }

可以预见的缺点是 如果友盟的sdk有更新，这段反射代码可能就会失效。