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Android Build a Weather App (2015) Hooking Up the Model to the View Plugging in the Data

Plugging in the Data Video

To plug in my data I had to use the newest version of Butterknife. Instead of using the @InjectView annotation, I am using the @BindView annotation, which does the same thing. I'm receiving a null pointer exception whenever I try to include the method updateDisplay. java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference Should I be converting this information to a String? If so, how? I have tried Double.toString() method, for whatever reason that didn't work and tried to force me to declare the variable as a string and then try that method, which still did not work. I'm at a total loss as to what to do next. Please help!

1 Answer

Seth Kroger
Seth Kroger
56,413 Points

Let's break down what "Attempt to invoke virtual method ... on a null object reference" You are trying to call a method (call and invoke are synonyms here). That method is setText(), which you are calling on the object to the left, a TextView. So the error message is saying that the TextView is null, not that there's any problem the data you're passing setText().

The most likely cause is a mismatch/typo in the id's you're binding between the Activity and XML for the layout, but htere can be other causes as well.