3

我需要将此对象存储到手机的内部存储器中，并且我 <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE"></uses-permission>在清单上有设置。对象本身有两个静态方法用于从内部存储器存储和重新加载它：

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;
}
}

我正在尝试在我的活动中使用此调用存储它并重新打开它：

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

但它不起作用，它没有存储对象，当然它也没有读取对象，我在存储和读取对象时遇到了这两个异常：

    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)

代码有什么问题？

谢谢

4

3 回答 3

6

改变这个

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

和

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

正如@ex 正确指出的那样，在清除应用程序数据或卸载应用程序时不会删除该文件

于 2012-03-23T09:27:23.487 回答
2

您不能只写入内部存储（即使您获得了该权限）。尝试使用外部 sd 或缓存文件夹。

于 2012-03-23T09:25:56.330 回答
1

这是我基于这篇文章和这个的方法

我在我的用户类上写了这个

private static File mFolder;
public void saveData(Activity pContext) {
    //this could be initialized once onstart up
    if(mFolder == null){
        mFolder = pContext.getExternalFilesDir(null);
    }
    this.save();
    ObjectOutput out;
    try {
        File outFile = new File(mFolder,
                "someRandom.data");
        out = new ObjectOutputStream(new FileOutputStream(outFile));
        out.writeObject(this);
        out.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static User loadData(Context pContext) {
    if(mFolder == null){
        mFolder = pContext.getExternalFilesDir(null);
    }
    ObjectInput in;
    User lUser = null;
    try {
        FileInputStream fileIn = new FileInputStream(mFolder.getPath() + File.separator + "someRandom.data");
        in = new ObjectInputStream(fileIn);
        lUser = (User) in.readObject();
        in.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    if (lUser != null) {
        lUser.save();
        Log.d("current User: ", lUser.nickname);
    } else {
        Log.d("current User: ", "null");
    }
    return lUser;
}

编辑：

然后从我的活动中我打电话

mUser = User.loadData(mSelf);

或者

mUser = User.loadData(this);

mSelf 将是我存储的实例

希望这可以帮助 ：）

于 2013-08-05T21:14:16.077 回答