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Java 如何使用内部存储器存储自定义对象的ArrayList?_Java_Android_Arraylist_Internal Storage - Fatal编程技术网

Java 如何使用内部存储器存储自定义对象的ArrayList?

Java 如何使用内部存储器存储自定义对象的ArrayList?,java,android,arraylist,internal-storage,Java,Android,Arraylist,Internal Storage,我想使用内部存储器存储名为WordList的自定义对象的ArrayList 这是我的密码: @SuppressWarnings("serial") public class WordList extends MainActivity implements Serializable { public String name; public ArrayList<String> wordarray; public ArrayList<String> definitionarr

我想使用内部存储器存储名为WordList的自定义对象的ArrayList

这是我的密码:

@SuppressWarnings("serial")
public class WordList extends MainActivity implements Serializable {

public String name;
public ArrayList<String> wordarray;
public ArrayList<String> definitionarray;

public WordList(String newName)
{
    this.name = newName;
    this.wordarray = new ArrayList<String>();
    this.definitionarray = new ArrayList<String>();
}

public String getName()
{
    return name;
}

private void writeObject(ObjectOutputStream out) throws IOException {
    out.writeUTF(name);
    out.writeObject(wordarray);
    out.writeObject(definitionarray);
}

private void readObject(ObjectInputStream in) throws IOException,
        ClassNotFoundException {
    name = in.readUTF();
    wordarray = (ArrayList<String>) in.readObject();
    definitionarray = (ArrayList<String>) in.readObject();
}  
}
@SuppressWarnings(“串行”)
公共类WordList扩展MainActivity实现可序列化{
公共字符串名称;
公共数组列表字数组;
公共数组列表定义数组;
公共单词列表(字符串newName)
{
this.name=newName;
this.wordarray=new ArrayList();
this.definitionarray=新的ArrayList();
}
公共字符串getName()
{
返回名称;
}
私有void writeObject(ObjectOutputStream out)引发IOException{
out.writeUTF(姓名);
out.writeObject(字数组);
out.writeObject(定义数组);
}
私有void readObject(ObjectInputStream in)引发IOException,
ClassNotFoundException{
name=in.readUTF();
.readObject()中的wordarray=(ArrayList);
.readObject()中的definitionarray=(ArrayList);
}  
}
以下是主要活动:

    public class MainActivity extends Activity {
private EditText text;
private ArrayList<WordList> lists = new ArrayList<WordList>();
private TextView textview;
FileOutputStream fos;
String filePath;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    text = (EditText) findViewById(R.id.editText1);
    textview = (TextView) findViewById(R.id.test);
    filePath = getApplicationContext().getFilesDir().getPath().toString() + ".fileName.txt";
}


public void onClick(View view) throws FileNotFoundException {
    switch (view.getId()) {
    case R.id.addtoarray:
        String input = text.getText().toString();
        WordList list = new WordList(input);
        lists.add(list);
        break;
    case R.id.save:
        try {
            File f = new File(filePath);
            FileOutputStream fos = new FileOutputStream(f, true);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            Toast.makeText(getApplicationContext(), "Wrote " + String.valueOf(lists.size() + "objects to file!"), Toast.LENGTH_LONG).show();
            oos.writeInt(lists.size());
            for(int i=0; i<lists.size(); i++)
            {
                oos.writeObject(lists.get(i));
            }
            oos.close();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        break;
    case R.id.load:
        File saveFile = new File(filePath);
        if (saveFile.exists())
        {
            Toast.makeText(getApplicationContext(), "File found!",
                    Toast.LENGTH_SHORT).show(); 
        try {
            FileInputStream fis = new FileInputStream(saveFile);
            ObjectInputStream ois = new ObjectInputStream(fis);
            int num = ois.readInt();
            for(int i = 0; i<num; i++)
            {
                WordList o = (WordList) ois.readObject();
                lists.add(o);
            }
            fis.close();
            ois.close();
        } catch (FileNotFoundException e) {
          e.printStackTrace();
      } catch (StreamCorruptedException e) {
          e.printStackTrace();
      } catch (IOException e) {
          e.printStackTrace();
      } catch (ClassNotFoundException e) {
          e.printStackTrace();
      }
    } else {
        Toast.makeText(getApplicationContext(), "File not found!",
              Toast.LENGTH_SHORT).show();
    }
        textview.setText(lists.get(0).getName());
        break;
    }
}
公共类MainActivity扩展活动{
私人编辑文本;
private ArrayList list=new ArrayList();
私有文本视图文本视图;
文件输出流;
字符串文件路径;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text=(EditText)findViewById(R.id.editText1);
textview=(textview)findViewById(R.id.test);
filePath=getApplicationContext().getFilesDir().getPath().toString()+“.fileName.txt”;
}
公共void onClick(视图)引发FileNotFoundException{
开关(view.getId()){
案例R.id.addtoarray:
字符串输入=text.getText().toString();
单词列表=新单词列表(输入);
列表。添加(列表);
打破
案例R.id.save:
试一试{
文件f=新文件(文件路径);
FileOutputStream fos=新的FileOutputStream(f,true);
ObjectOutputStream oos=新的ObjectOutputStream(fos);
Toast.makeText(getApplicationContext(),“writed”+String.valueOf(lists.size()+“objects to file!”),Toast.LENGTH\u LONG.show();
oos.writeInt(lists.size());

对于(int i=0;i您可以分两步执行:
1.您需要能够将WordList对象转换为字符串对象/变量,反之亦然。您可以使用注释中的建议来解决问题。
2.然后,您将能够使用SharedReferences保存字符串对象

在代码中,您将执行以下操作:
1.当需要在内存中保存对象时,可将其转换为字符串:

String my_object = GetStringFromMyObject(object_to_save);
2.然后将其保存在SharedReferences中:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("my_object_key", my_object);
3.最后,您可以随时恢复该值:

MyObject object_to_restore = GetMyObjectFromString(prefs.getString("my_object_key", "default_value));

使用GSON库,将对象转换为
字符串对象
,并存储在内部存储器中(共享首选项)