这是什么原因？

Question

  Process: com.weather.com.welcomeactivity, PID: 8304

    java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference

 at com.weather.com.welcomeactivity.utils.CacheUtils.getString(CacheUtils.java:46)

 at com.weather.com.welcomeactivity.shoppingcart.utils.CartProvider.getDataFromLocal(CartProvider.java:73)

  at com.weather.com.welcomeactivity.shoppingcart.utils.CartProvider.getAllData(CartProvider.java:66)

   at com.weather.com.welcomeactivity.shoppingcart.utils.CartProvider.listToSparse(CartProvider.java:44)

    at com.weather.com.welcomeactivity.shoppingcart.utils.CartProvider.<init>(CartProvider.java:32)

    at com.weather.com.welcomeactivity.shoppingcart.utils.CartProvider.getInstance(CartProvider.java:38)

    at com.weather.com.welcomeactivity.app.GoodsInfoActivity.onClick(GoodsInfoActivity.java:163)

    at android.view.View.performClick(View.java:5637)

    at android.view.View$PerformClick.run(View.java:22429)

    at android.os.Handler.handleCallback(Handler.java:751)

    at android.os.Handler.dispatchMessage(Handler.java:95)

    at android.os.Looper.loop(Looper.java:154)

    at android.app.ActivityThread.main(ActivityThread.java:6119)

    at java.lang.reflect.Method.invoke(Native Method)

    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)

    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

                                                                               

                                                                               

Answer 1

NullPointerException，这个单词的意思就是说你的代码运行到某一步的时候报空指针异常了，后面那些就是说的是你代码的行数，哪一行有问题。