所以我有这个我正在处理的项目,我需要为它创建自己的 ArrayList 类。我已经定义了所有方法,但是当我编译时,我的三个方法不断收到“找不到符号”错误。我有一个看起来像这样的界面:
public interface FBList {
public int size();
public void insert(int i, Person person);
public Person remove(int i);
public Person lookUp(int i);
/**
*A class that defines a person
**/
public class Person {
private String id;
private long phoneNum;
public Person(String personID, long phoneNum){
id = personID;
phoneNum = phoneNum;
}
}
如您所见,我在那里有一个内部类。我正在尝试在实现此接口的其他文件中使用该类。目前,我的另一个文件中给我的问题的三种方法如下:
/**
* A method to expand the size of the array if the array is too small
* @param i One minus the place in the list where the component will be inserted
* @param Person The person to be put in the list
**/
protected void expandInsert(int i, Person person){
Person[] temp = new Person[arrayList.length * 2];
for(int index = 0; index < temp.length; index++){
if( i != index){
if(i > 0)
temp[index] = arrayList[index];
if(i == 0)
temp[index + 1] = arrayList[index];
}
else{
temp[i] = person;
i = 0;
index--;
}
}
arrayList = temp;
}
/**
* Inserts a new component at the end of a list by creating a new list longer that then last
* @param i The place in the list where the component will be inserted
* @param Person The person to be added to the list
**/
protected void insertAtEnd(int i, Person person){
Person[] temp = new Person[arrayList.length + 5];
for(int index = 0; index < temp.length; index++){
if(index != i){
temp[index] = arrayList[index];
}
else{
temp[index] = person;
}
}
arrayList = temp;
}
/**
* Shrinks the array by one by removing one component from the array
* @param i The index to be removed
**/
protected void shrink(int i){
Person[] temp = new Person[arrayList.length - 1];
for (int index = 0; index < arrayList.length ; index++ ) {
if (index < i) {
temp[index] = arrayList[index];
}
else if (index == i){
removedPerson = arrayList[index];
temp[index] = arrayList[index + 1];
}
else{
temp[index - 1] = arrayList[index];
}
}
}
所有这些文件都在同一个文件夹中,所以那里不应该有问题。我正在使用终端通过键入“javac FBArrayList.java”进行编译。我的编译器输出如下所示:
FBArrayList.java:106: cannot find symbol
symbol : method expandInsert(int,FBList.Person)
location: class FBList.Person[]
arrayList.expandInsert(i, person);
^
FBArrayList.java:108: cannot find symbol
symbol : method insertAtEnd(int,FBList.Person)
location: class FBList.Person[]
arrayList.insertAtEnd(i, person);
^
FBArrayList.java:118: cannot find symbol
symbol : method shrink(int)
location: class FBList.Person[]
arrayList.shrink(i);
^
3 errors