Using variables in one class in another class NullpointerException - RunTimeException

Question

I tried to do something extremely simple or I thought it was.

In my BluetoothChat, I set

public static boolean potato = false;

In the onCreateBundle of my MainActivity, I have

if(BluetoothChat.potato == false)
{
  tv.setText("it did not crash");
}

My application crashes immediately upon me switching windows from bluetoothchat to mainactivity. I receive java.lang.RuntimeException and java.lang.NullPointerException. However, the application does not crash and switches perfectly if I have the if statement commented out.

Answer 1

It looks like the error is coming from tv, not BlueToothChat.potato. Have you initialized the "tv" variable at that point in the code?