大家好，提前抱歉我的问题写得不好。我只允许4个类，电影，Moviedatabase，播放列表和界面。在界面方法播放列表中，
1.我正在尝试将对象数组存储到对象数组中，并不是每个人都确定如何这样做。由于播放列表数组可以调整大小。
2.当我尝试使用Moviedatabase中的list方法打印我的结果时，我只得到空行。困惑为什么
编辑。这是一个学校的评估，并没有完成所以..我猜这里和那里会有相当多的错误。
public class Interface
{
//create a scanner
static Scanner input = new Scanner(System.in);
static MovieDatabase md = new MovieDatabase();
static Playlist p = new Playlist();
private int total = 0;
private Playlist[] playlistArray = [total];
private Playlist[] playlist;
public static void main (String [] args)
{
int choice = 0;
while(choice != 15)
{
showSelection();
choice = input.nextInt();
input.nextLine();
switch(choice)
{
case 1: addMovie();
break;
case 2: md.list(1,"",0);
break;
case 3: System.out.println("What is the name of the movie you wish to delete?");
String name = input.nextLine();
md.delete(name);
break;
case 4: editMovie();
break;
case 5: directorList();
break;
case 6: durationList();
break;
case 7: playlist();
case 13: copyFile();
break;
case 14: openFile();
break;
case 15: System.exit(0);
break;
}
}
}
public static void addMovie()
{
String name,director;
double filesize,duration;
System.out.println("What is the Name of the Movie:");
name = input.nextLine();
System.out.println("What is the Director of the Movie:");
director = input.nextLine();
System.out.println("What is the Duration of the Movie in minutes:");
filesize = input.nextDouble();
System.out.println("What is the Filesize of the Movie in mb:");
duration = input.nextDouble();
md.addMovie(name,director,filesize,duration);
}
public static void editMovie()
{
System.out.println("What is the name of the movie you wish to edit?");
String name = input.nextLine();
System.out.println("Please retype the information of the movie you wish to edit");
System.out.println("What is the Name of the Movie:");
String mname = input.nextLine();
System.out.println("What is the Director of the Movie:");
String director = input.nextLine();
System.out.println("What is the Duration of the Movie in minutes:");
double filesize = input.nextDouble();
System.out.println("What is the Filesize of the Movie in mb:");
double duration = input.nextDouble();
md.edit(name,mname,director,filesize,duration);
}
public static void directorList()
{
System.out.println("What is the name of the director?");
String director = input.nextLine();
md.list(2,director,0);
}
public static void durationList()
{
System.out.println("Duration the movies have to be under in Minutes");
double duration = input.nextDouble();
md.list(3,"",duration);
}
public static void playlist()
{
playlist[total] = new Playlist();
total++;
System.out.println("How many movies do you wish to save in this playlist?");
num int = input.nextInt();
storage = new Playlist();
for(int i = 0; i < num; i ++)
{
System.out.println("Type in the next movie:").
String name = nextLine;
if(md.check(name)==1)
{
storage[i] = md.getMovie1(name);
}
else if(md.check(name)==0)
{
System.out.println("Movie you typed does not exist");
i--;
}
}
playlistarray[total] = storage;
if(total == playlist.length)
{
increaseResize();
}
}
public static void increasseResize()
{
Playlist[] replaylist;
replaylist = new Playlist[playlist.length+1];
for(int i = 0; i < playlist.length; i++)
{
replaylist[i] = playlist[i];
}
playlist = replaylist;
}
public static void copyFile()
{
String fileName = "out.text";
PrinterWriter outputStream = null;
try
{
outputStream = new PrintWriter (fileName);
}
catch (FileNotFoundException e)
{
System.out.println ("error opening the file");
System.exit (0);
}
for(int i = 0; i < md.total; i++)
{
outputStream.println(md.getName(i) + line);
outputStream.println(md.getDirector(i) + line);
outputStream.println(md.getFilesize(i) + line);
outputStream.println(md.getDuration(i) + line);
}
outputStream.close();
}
public static void openFile()
{
String fileName = "readMe";
System.out.println ("The file " + fileName + "\ncontains the following lines:\n");
Scanner inputStream = new Scanner (new File (fileName));
while (inputStream.hasNextLine ())
{
if(inputStream.hasNextInt())
{
while(inputStream.hasNextInt())
{
System.out.print(inputStream.nextInt());
}
}
else
{
String line = inputStream.nextLine ();
System.out.println (line);
}
}
inputStream.close ();
}
public static void showSelection()
{
System.out.println("1.Add Movies");
System.out.println("2.Show All Movies Currently Listed");
System.out.println("3.Delete a Movie");
System.out.println("4.Edit an Existing Movie");
System.out.println("5.Show All Movies from certain Director");
System.out.println("6.Show all Movies under a certain Duration");
System.out.println("7.Create a Playlist");
System.out.println("");
System.out.println("");
System.out.println("");
System.out.println("");
System.out.println("");
System.out.println("13.Save Current movie database to a file");
System.out.println("14.Open a movie database from a file");
System.out.println("15.End Program");
}
}
public class Movie
{
private String name;
private String director;
private double filesize;
private double duration;
public Movie()
{
name = "";
director = "";
filesize = 0;
duration = 0;
}
//setting the method name
public void setName(String name)
{
name = name;
}
//getting the method name
public String getName()
{
return name;
}
//setting the method director
public void setDirector(String director)
{
director = director;
}
//getting the method director
public String getDirector()
{
return director;
}
// setting the method filesize
public void setFilesize(double filesize)
{
filesize = filesize;
}
//getting the method filesize
public double getFilesize()
{
return filesize;
}
//setting the method duration
public void setDuration(double duration)
{
duration = duration;
}
//getting the method duration
public double getDuration()
{
return duration;
}
}
public class MovieDatabase
{
final private int MAX = 5;
private Movie[] movies;
private int total;
public MovieDatabase()
{
movies = new Movie[MAX];
total = 0;
}
public void addMovie(String newName, String newDirector, double newFileSize, double newDuration)
{
if(check(newName) == 0)
{
movies[total] = new Movie();
setMovie(movies[total],newName,newDirector,newFileSize,newDuration);
total++;
if(total == movies.length)
{
increaseResize();
}
}
else if(check(newName) == 1)
System.out.println("Movie already exists");
}
private void setMovie(Movie m,String newName, String newDirector, double newFileSize, double newDuration)
{
m.setName(newName);
m.setDirector(newDirector);
m.setFilesize(newFileSize);
m.setDuration(newDuration);
}
public int movieTotal()
{
return total;
}
public double check(String name)
{
if(total > 0)
{
for(int i = 0; i < total; i++)
{
if(movies[i].getName() == name)
{
return 1;
}
else
return 0;
}
}
else
return 0;
}
public String getMovie1(String name)
{
int i = position(name);
setMovie = movies[i].getName();
return setMovie;
}
public getMovie(int i)
{
String nom = movies[i].getName();
return nom;
}
public getDirector(int i)
{
String nom = movies[i].getDirector();
return nom;
}
public getFilesize(int i)
{
String nom = movies[i].getFilesize();
return nom;
}
public getDuration(int i)
{
String nom = movies[i].getDuration();
return nom;
}
private void increaseResize()
{
Movie [] removie;
removie = new Movie[movies.length+1];
for(int i = 0; i < movies.length; i++)
{
removie[i] = movies[i];
}
movies = removie;
}
public void list(int n,String name,double number)
{
//display all Movies
if(n == 1)
{
if(total>0)
{
for(int i = 0; i < total; i++)
{
System.out.println(movies[i].getName());
}
}
else
{
System.out.println("Cannot Display Movies if you haven't saved any yet.");
}
}
//Display all Movies under certain Director
else if(n == 2)
{
if(total > 0)
{
for(int i = 0; i < total; i++)
{
if(movies[i].getDirector() == name)
{
System.out.println(movies[i].getName());
}
}
}
else
{
System.out.println("Either no Movies exist or their are no movies under that Directors name");
}
}
//Display all Movies under certain Durtation
else if(n == 3)
{
if(total > 0)
{
for(int i = 0; i < total; i++)
{
if(movies[i].getDuration() == number)
{
System.out.println(movies[i].getName());
}
}
}
else
{
System.out.println("Either no Movies exist or their are no movies under that Directors name");
}
}
}
public void edit(String name, String newName, String newDirector, double newFileSize, double newDuration)
{
int p;
p = position(name);
movies[p] = new Movie();
for(int i = -2; i < total -1; i++)
{
if(p == -1)
{
System.out.println("The Movie you wish to delete does not exist");
}
else if(i == p)
{
setMovie(movies[p],newName,newDirector,newFileSize,newDuration);
}
}
}
public void delete(String name)
{
int p;
p = position(name);
if(p == -1)
{
System.out.println("The Movie you wish to delete does not exist");
}
else
{
for(int i = p; i < total -1; i++)
{
movies[i] = movies[i+1];
total --;
}
}
}
private int position(String name)
{
for(int i = 0; i < total; i++)
{
if(movies[i].getName() == name)
return i;
}
return -1;
}
}
public class Playlist
{
final private int MAX = 4;
final private int MAX_TIME = 1000;
final private int MAX_SIZE = 20000;
private Movie[] movies;
private int total;
public Playlist()
{
movies = new Movie[MAX]
}
}
`
答案 0 :(得分：0)
由于您需要在Playlist中使用Storage的dinamic数组，因此您只需使用List<Playlist>。
类似的东西：
List<Playlist> storage = new ArrayList<Playlist>();
System.out.println("How many movies do you wish to save in this playlist?");
num int = input.nextInt();
Playlist p = new Playlist();
for(int i = 0; i < num; i ++)
{
System.out.println("Type in the next movie:").
String name = nextLine;
//Verifications
if(md.check(name) == 1)
storage[i] = md.getMovie1(name);
else if(md.check(name) == 0)
{
System.out.println("Movie you typed does not exist");
i--;
}
//Add the movie to Playlist
p.add(md.getMovie1(name);
}
storage.add(p);
答案 1 :(得分：0)
猜测您的MD类返回Storage
类型的东西 public static void playlist()
{
final List<Object> playlist = new ArrayList();
final Scanner finput = new Scanner(System.in);
String input;
System.out.println("How many movies do you wish to save in this playlist?");
int num = input.nextInt();
// final List<Object> storage = Storage.getStorage();
for(int i = 0; i < num; i ++)
{
System.out.println("Type in the next movie:").
String name = finput.nextLine();
if(md.check(name)==1)
{
playlist.add(md.getMovie1(name));
}
else
{
System.out.println("Movie you typed does not exist");
i--;
}
}
}
如果不是playlist.add()，您可以添加storage.get(name)。
但是没有从你的代码中看到更多，只是在猜测。