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Java Java Data Structures - Retired Efficiency! Changing Course

Patrick Koch
Patrick Koch
40,498 Points

Can't add Video to created List

Hello,

I Watched the List video and checked the our Karaoke code, but I cant figure out whats wrong, Compiler is telling me about a runtime error.

I put notes in the code, for my thoughts.

thanks

g patrick

com/example/model/Course.java
package com.example.model;

import java.util.List;

public class Course {
  private String mName;
  private List<Video> mVideos; 

  public Course(String name, List<Video> videos) {
    mName = name;
    mVideos = videos;
  }

  public String getName() {
    return mName;
  }

  public List<Video> getVideos() {
    return mVideos;
  }

}
com/example/model/Video.java
package com.example.model;

public class Video {
  private String mTitle;

  public Video(String title) {
    mTitle = title;
  }

  public String getTitle() {
    return mTitle;
  }

  public void setTitle(String title) {
    mTitle = title;
  }

}
QuickFix.java
import com.example.model.Course;
import com.example.model.Video;


import java.util.Map;
import java.util.List;
import java.util.ArrayList;

public class QuickFix {

  public void addForgottenVideo(Course course) {
    // TODO(1):  Create a new video called "The Beginning Bits"
    Video forgottenVideo = new Video("The Beginning Bits");


    // TODO(2):  Add the newly created video to the course videos as the second video.
    //create List
    List<Video> completedList = new ArrayList<Video>();
    //add created Video to list (0 based, so 1)
    completedList.add(1, forgottenVideo);
  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {

  }

  public Map<String, Video> videosByTitle(Course course) {
    return null;
  }

}

2 Answers

Dan Johnson
Dan Johnson
40,533 Points

Since you're trying to update a list that already exists you'll want to grab the reference to it instead of creating a new list.

// Get the list from the course.
List<Video> completedList = course.getVideos();
Patrick Koch
Patrick Koch
40,498 Points

Thanks Dan,

afterwards its so obvious!

thanks again, Patrick