Question

我创建了一个单例类，它是一个Boat列表。我正在为MainActivity的Action Bar创建一个选项，它将根据用户输入船的注册情况显示有关船的信息。如果它在列表中找到注册，它应该在TextView上附加有关该特定船只注册的所有信息。但是，我不断收到我的错误消息。我认为原因在于我的for循环语句或它的正文，但我不太确定。这是我的代码看起来像（我还将提供列表，BoatList又名我的单例类和我的主代码下面的常规类Boat）：

public void showBoat(View view)
{
    //Declare references and variables
    EditText et;
    TextView tv;
    ImageView im;
    BoatList boat_list;
    String boatRegist;

    //Set references
    et = (EditText) findViewById(R.id.edit_boat_regist);

    tv = (TextView) findViewById(R.id.text_main);

    im = (ImageView) findViewById(R.id.image_area);

    boat_list = BoatList.getInstance();

    //Get user input
    boatRegist = et.getText().toString();

    //Search through the list and try to find the boat by registration

    int i;
    for(i = 0; i < boat_list.size(); i++)
    {
        if(boatRegist == boat_list.get(i).getRegi())
        {
            tv.append(boat_list.get(i).getMake() + "\n" + boat_list.get(i).getRegi() +
                    "\n" + boat_list.get(i).getYear() + "\n" + boat_list.get(i).getLength() 
                    + "\n" + boat_list.get(i).getBeam() + "\n" + boat_list.get(i).getFuel() +
                    "\n" + boat_list.get(i).getPrice() + "\n" + boat_list.get(i).getAge()
                    + "\n");
        }
        else
            Toast.makeText(ShowBoatActivity.this, "Error: The registration is invalid!", 
                    Toast.LENGTH_SHORT).show();
    }

    //Open the picture from the URL address
    /*
    ImageDownloader idl = new ImageDownloader();
    idl.download(boat_list.get(i).getPicURL(), im);*/

}

以下是我的Singleton类：

import java.util.LinkedList;


public final class BoatList extends LinkedList<Boat>
{

private static BoatList instance = null;


private BoatList()
{
    // Exists only to defeat additional instantiations.
}

//Define method
public static BoatList getInstance()
{
    if(instance == null)
        instance = new BoatList();

    return instance;
}

} //end BoatList

最后，这是我的常规班，船：

public class Boat {

//Declare data members
private String make;
private String registeration;
private int year;
private int length;
private int beam;
private String fuel;
private double price;
private String picURL; 
private int age;
private double priceLT;

//Define the methods
public String getMake()
{
    return make;
}

public void setMake(String m)
{
    make = m;
}

public String getRegi()
{
    return registeration;
}

public void setRegi(String r)
{
    registeration = r;
}

public int getYear()
{
    return year;
}

public void setYear(int y)
{
    year = y;
}

 public int getLength()
 {
    return length;
 }

 public void setLength(int L)
 {
    length = L;
 }

 public int getBeam()
 {
     return beam;
 }

 public void setBeam(int b)
 {
    beam = b;
 }

public String getFuel()
{
    return fuel;
}

public void setFuel(String f)
{
    fuel = f;
}

public double getPrice()
{
    return price;
}

public void setPrice(double p)
{
    price = p;
}

public String getPicURL()
{
    return picURL;
}

public void setPicURL(String url)
{
    picURL = url;
}

public int getAge()
   {

    int currentYear = 2015;

    //Calculate the age of the boat 
    age = currentYear - year;

    return age;
}

public double getLuxuryTax()
{
    //Declare variables
    double newPrice;
    double luxTax = .15;

    //Calculate the price with luxury tax if the first condition
    //is found to be True. 
    if (length >= 50 && age <= 10)
    {
        newPrice = price * luxTax;
        priceLT = price + newPrice;

        if (priceLT == 0)
        {
            priceLT = (Double) null;    
            return priceLT;
        }
    }

    return priceLT;
}

}

Answer 1

您正在使用==来比较注册值，您应该使用.equalsIgnoreCase(str) reference来确保用户的输入在他/她使用小写字母而非资本时进行积极比较。

为什么我的列表输出不正确？

1 个答案: