Double Max issues

Results 4 issues of


                                            Double Max

加入gradle支持后编译出错

我添加了依赖后，android studio编译无法通过，控制台报错： ![_20180226190317](https://user-images.githubusercontent.com/11400746/36667187-ffe61780-1b27-11e8-9df7-aff345c9ab9a.png) 请问这是什么原因？

PhotoPickerActivity内存泄露

打开横竖屏旋转，在图片选择页面，竖屏切换到横屏，发现有内存泄露的情况。 ![qq 20180608105405](https://user-images.githubusercontent.com/11400746/41136900-0acd3d4e-6b0b-11e8-92b6-04ada6835dcd.png)

竖屏切换横屏时报异常：java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference

进入PhotoPickerActivity，由竖屏切换到横屏时出现了异常，以下是异常信息： java.lang.RuntimeException: Unable to start activity ComponentInfo{org.zuicool.studentapp/me.iwf.photopicker.PhotoPickerActivity}: java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2448) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2510) at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4226) at android.app.ActivityThread.access$1300(ActivityThread.java:163) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1381)...

Update MediaObject.java

错别字:)