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Android Build an Interactive Story App (Retired) The Model-View-Controller Pattern Adding a Custom Constructor

Posted by Joseph Collins
Joseph Collins
802 Points

Constructor with input string

Hello, I'm having trouble with one of the exercises. I've made the first constructor which defines mType as "SHUTTLE".

But I'm stuck on the second part of the question which says "Using a second constructor, with a string, update mType to read a different type of spaceship.

I've tried a number of things, this one looked the closest but I get a java.lang.nullexception error. I'm sure I'm missing something really obvious but I can't find it. Thanks very much

Spaceship.java 
public class Spaceship {
    public String mType;

    public String getType() {
      return mType;
    }

    public void setType(String type) {
      mType = type;
    }

  public Spaceship() {
   mType = "SHUTTLE"; 
  }

  public Spaceship(String mType) {
   mType = "ROCKET"; 
  }
}

1 Answer

Zack Klinger
Zack Klinger
17,622 Points
Zack Klinger
Zack Klinger
17,622 Points

Don't name the String variable you are passing "mType" which is the same name as your private member variable, "mType".

try something like, public Spaceship (String to_set)

and then it would look like mType = to_set;

Joseph Collins
Joseph Collins
802 Points

Ah, I understand now. The exercise is about defining the constructors, and the second example is for when the constructor is called with a string.

Cheers Zack!