重现步骤：打开app操作地图，把app转入后台，再打开，APP崩溃
请问是不是哪里设置不对或者地图的使用中要注意什么？比如地图的创建和释放是不是要注意什么？
崩溃日志如下：
0. Crashed: GLThread 14353
at com.baidu.platform.comapi.map.MapRenderer.onDrawFrame(Unknown Source:46)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1609)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1293)
--
Fatal Exception: java.lang.NullPointerException: Attempt to read from field 'java.util.List com.baidu.platform.comapi.map.e.f' on a null object reference
at com.baidu.platform.comapi.map.MapRenderer.onDrawFrame(Unknown Source:46)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1609)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1293)
0. Crashed: GLThread 14353
at com.baidu.platform.comapi.map.MapRenderer.onDrawFrame(Unknown Source:46)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1609)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1293)