Java. Lang. nullpointerexception

Two days ago, I had to hand in a small Android item. I wanted to display a list of information from the previous activity on the new activity, but I had not adjusted the bug when I handed in the item, java. lang. nullpointerexception. I had to cancel this function. then I looked back and found that I was mentally retarded and made a mistake. before I jumped from activity A to Activity B, the data was filled into the bundle structure, but the intent was not written. add (bundle ).... the receiving page also lacks a mechanism to handle exceptions. Before obtaining data, it does not determine whether the bundle is null. so that when the error is found, if it is not a line of careful reading of your code,
The specific location of the error cannot be found from a simple error.

Just a few days later, I am still not familiar with Android. In the future, I will avoid such mentally retarded errors.