Question

我有一个相当简单的课程。

package com.example.myapp;

public class Preset implements Serializable{
/**
 * Gernerated Serial Id For Serialization
 */
private static final long serialVersionUID = -183094847073879300L;{

private String name;
private int id;
private float speed;
private boolean moving;

public Preset(String name, int id, float speed, boolean moving){
    this.name = name;
    this.id = id;
    this.speed = speed;
    this.moving = moving;
}

public String getName(){
    return this.name;
}

public int getId(){
    return this.id;
}

}

我有另一个类创建这些预设的列表

public class PresetList extends PreferenceActivity implements Serializable{
/**
 * Default Serial Id for Serialization
 */
private static final long serialVersionUID = 1L;
private List<Preset> presetList = new ArrayList<Phys>();
private int listSize = 0;

/* Constructor */
public PresetList(){
    // Allows Access To Our List
}

public void addToList(Preset p){
    presetList.add(p);
    listSize++;
    saveList(presetList);
}

public void removeFromList(int listLocation){
    presetList.remove(listLocation);
    listSize--;
    saveList(presetList);
}

public int getListSize(){
    return listSize;
}

在同一个类中调用这些方法

/* Save Object Through Serialization */
@SuppressLint("SdCardPath")
public void saveList(List<Preset> pl){
    try
    {
       String fileName = Environment.getExternalStorageDirectory() + File.separator + 
               "Android" + File.separator + "data" + File.separator + "presets_list.bin";
       File presetListFile = new File(fileName);
           try{
               presetListFile.createNewFile();
           }
           catch (IOException e){
               Log.d("IOException", "File exception " + e.getMessage());
           }

       ObjectOutputStream outputStream = new ObjectOutputStream(
               new FileOutputStream(presetListFile)); //Select where you wish to save the file...
       outputStream.writeObject(pl); // write the class as an 'object'
       outputStream.flush(); // flush the stream to insure all of the information was written to 'save_object.bin'
       outputStream.close();// close the stream
    }
    catch(Exception e)
    {
       Log.d("IOException","Serialization Write Error: " + e.getMessage());
    }
}

// Retrieve List through Desearialization
@SuppressWarnings("unchecked")
public List<Preset> loadList(File f){
    try
    {
        ObjectInputStream inputStream = new ObjectInputStream(new FileInputStream (f));
        Object o = inputStream.readObject();
        presetList= (List<Preset>) o;
        return presetList;
    }
    catch(Exception e){
        Log.d("IOException", "Serialization Read Error : " + e.getMessage());
    }
    return null;
}

}

当我尝试创建列表时，我收到错误

Serialization Read Error : Read an exception; java.io.NotSerializableException: com.example.myapp.Preset

我哪里错了？如果它不可序列化，它在尝试读取之前如何写入？

Answer 1

您需要实现Serializable。

使用Android编写/读取类的序列化问题

1 个答案: