试图从另一个类访问字符串？

Question

我无法从我的Picture类访问String说明，以便在PhotoViewer类中使用它。我创建了一个getter方法，所以我不明白为什么我得到错误

无法找到符号 - 方法getDescription（）。

下面是代码：

/** 
* Write a description of class Picture here. 
* 
* @author (your name) 
* @version (a version number or a date) 
*/ 
public class Picture extends Attachment 
{ 
    protected String description; 
    protected String height; 
    protected String width; 

    /** 
    * Constructor for objects of class Picture 
    */ 
    public Picture(String filename, long size, String description, String height, String width) 
    { 
     this.filename = filename; 
     this.size = size; 
     this.description = description; 
     this.height = height; 
     this.width = width; 
    } 

    /** 
    * Prints out the details of a picture attachment. 
    */ 
    public void preview() 
    { 
     System.out.println("Filename: " + filename); 
     System.out.println("Size: " + size); 
     System.out.println("Description: " + description); 
     System.out.println("Height: " + height); 
     System.out.println("Width: " + width); 
    } 

    /** 
    * Getter method that returns the description 
    */ 
    public String getDescription() 
    { 
     return description; 
    } 
} 

/** 
* Application to open and view photos 
* 
* @author Chandler Warren 
* @version 12-1-15 
*/ 
public class PhotoViewer extends Application 
{ 
    Picture picture; 

    /** 
    * Constructor for objects of class PhotoViewer 
    */ 
    public PhotoViewer() 
    { 

    } 

    /** 
    * Abstract method to open the attachment 
    */ 
    public void open(Attachment picture) 
    { 
     System.out.println("I am the PhotoViewer. You are viewing a picture of " + getDescription()); 
    } 
} 

New error encountered when trying to initiate picture

Answer 1

public void open(Attachment picture) 
{ 
    System.out.println("I am the PhotoViewer. You are viewing a picture of " + picture.getDescription()); 
} 

将工作假设picture正确instatiated（目前尚不清楚，如果你想使用实例变量或th e方法变量，这个例子调用方法变量，但this.picture会调用实例变量）。 getDescription()是一个实例方法，因此必须从一个对象中调用。

Answer 2

这是解决方案。我用铸造。