如何将一个类的对象存储到内部存储器存储使用序列化？ [英] How to store a class object into Internal Memory Storage using serializable?

问题描述

我需要这个对象存储到手机的内部存储内存，和我有＆LT;使用-权限的Andr​​oid：名称=android.permission.WRITE_INTERNAL_STORAG​​E＆GT;＆LT; /用途-permission＆GT; 货单上设置。对象本身富人两个静态方法存储和从内部存储器中重新加载它：

I need to store this object into the internal storage memory of the phone, and i have the <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE"></uses-permission> set on the manifest. The object itself haves two static methods for store and reload it from the internal memory:

public class SaveState implements Serializable {
static public List<FullMagazine> fms = new ArrayList<FullMagazine>();
static SaveState instance=null;

public static SaveState getInstance(){      
    if( instance == null )
        instance = new SaveState();     
    return instance;
}

public static void saveData(SaveState instance){
    ObjectOutput out;
    try {
        out = new ObjectOutputStream(new FileOutputStream("appSaveState.data"));        
        out.writeObject(instance);
        out.close();
    } catch (Exception e) {e.printStackTrace();}
}

public static SaveState loadData(){
    ObjectInput in;
    SaveState ss=null;
    try {
        in = new ObjectInputStream(new FileInputStream("appSaveState.data"));       
        ss=(SaveState) in.readObject();
        in.close();
    } catch (Exception e) {e.printStackTrace();}
    return ss;
}
}

我试图来存储并使用该电话在我的活动重新打开：

I'm trying to store it and reopen it using this call in my activity:

            SaveState.fms.add(fm);
            SaveState.saveData(SaveState.getInstance());                
            SaveState sv = SaveState.loadData();

但它不工作，它不是存储的对象，ofcourse它不读objecto，我得到这两个例外，同时存储和读取的对象：

But it is not working, it is not storing the object, and ofcourse it is not reading the objecto, i'm getting these two exception while storing and reading the object:

    03-23 09:18:16.702: WARN/System.err(9060): java.io.FileNotFoundException: /appSaveState.data (Read-only file system)
03-23 09:18:16.702: WARN/System.err(9060):     at org.apache.harmony.luni.platform.OSFileSystem.openImpl(Native Method)
03-23 09:18:16.702: WARN/System.err(9060):     at org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:152)
03-23 09:18:16.702: WARN/System.err(9060):     at java.io.FileOutputStream.<init>(FileOutputStream.java:97)
03-23 09:18:16.702: WARN/System.err(9060):     at java.io.FileOutputStream.<init>(FileOutputStream.java:168)
03-23 09:18:16.702: WARN/System.err(9060):     at java.io.FileOutputStream.<init>(FileOutputStream.java:147)
03-23 09:18:16.702: WARN/System.err(9060):     at com.Magazine.SaveState.saveData(SaveState.java:35)
03-23 09:18:16.702: WARN/System.err(9060):     at com.Magazine.MainMenu$DownloadThread.run(MainMenu.java:807)
03-23 09:18:16.709: WARN/System.err(9060): java.io.FileNotFoundException: /appSaveState.data (No such file or directory)
03-23 09:18:16.709: WARN/System.err(9060):     at org.apache.harmony.luni.platform.OSFileSystem.openImpl(Native Method)
03-23 09:18:16.709: WARN/System.err(9060):     at org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:152)
03-23 09:18:16.709: WARN/System.err(9060):     at java.io.FileInputStream.<init>(FileInputStream.java:82)
03-23 09:18:16.709: WARN/System.err(9060):     at java.io.FileInputStream.<init>(FileInputStream.java:134)
03-23 09:18:16.709: WARN/System.err(9060):     at com.Magazine.SaveState.loadData(SaveState.java:46)
03-23 09:18:16.709: WARN/System.err(9060):     at com.Magazine.MainMenu$DownloadThread.run(MainMenu.java:809)

什么是错在code？

What's wrong in the code?

感谢

推荐答案

改变这种

out = new ObjectOutputStream(new FileOutputStream("appSaveState.data"));

与

   File outFile = new File(Environment.getExternalStorageDirectory(), "appSaveState.data");
   out = new ObjectOutputStream(new FileOutputStream(outFile)); 

为正确地指出@ex，该文件将不会被删除清除应用程序的数据或卸载应用程序

as correctly pointed out by @e-x, the file will not be removed clearing application's data or uninstalling the app

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