BUG省市区三级联动

一级一级快速滑动，程序奔溃，报
java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
at com.bigkoo.pickerview.lib.WheelView.measureTextWidthHeight(WheelView.java:253)
at com.bigkoo.pickerview.lib.WheelView.remeasure(WheelView.java:220)
at com.bigkoo.pickerview.lib.WheelView.setAdapter(WheelView.java:329)
at com.bigkoo.pickerview.view.WheelOptions$2.onItemSelected(WheelOptions.java:118)
at com.bigkoo.pickerview.lib.OnItemSelectedRunnable.run(OnItemSelectedRunnable.java:12)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:5728)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)