我正在为android设计一个手写应用程序。
class LogInfo每次用户按下回车按钮时，我都想将信息 ( ) 写入日志文件。
之后，我想阅读存储的信息。
这是我的课程的一部分，带有自定义写入方法：
public class LogInfo implements Serializable {
private static final long serialVersionUID = -5777674941129067422L;
public static List<Point[][]> strokes;
public static List<byte[]> codes;
// Only write and read methods shown
private void writeObject(ObjectOutputStream stream) throws IOException
{
stream.defaultWriteObject();
stream.writeInt(strokes.size());
Point[][] pointsArray = null;
for (int i = 0; i < strokes.size(); i++)
{
pointsArray = ((Point[][])strokes.get(i));
stream.writeInt(pointsArray.length);
for (int j = 0; j < pointsArray.length; j++)
{
stream.writeInt(pointsArray[j].length);
for (int k = 0; k < pointsArray[j].length; k++)
{
stream.writeInt(pointsArray[j][k].x);
stream.writeInt(pointsArray[j][k].y);
//stream.writeObject(elementData[i]);
}
}
}
int size = codes.size();
stream.writeInt(size);
for (int i = 0; i < size; i++)
{
stream.write(codes.get(i));
}
}
这是读取方法：
private void readObject(java.io.ObjectInputStream stream)
{
stream.defaultReadObject();
int strokesSize = stream.readInt();
for (int i = 0; i < strokesSize; i++)
{
int arrayXSize = stream.readInt();
Point[][] points = new Point[arrayXSize][];
for (int j = 0; j < arrayXSize; j++)
{
int arrayYSize = stream.readInt();
points[j] = new Point[arrayYSize];
for (int k = 0; k < arrayYSize; k++)
points[j][k] = new Point(stream.readInt(), stream.readInt());
}
strokes.add(points);
}
int codesSize = stream.readInt();
for (int i = 0; i < codesSize; i++)
{
byte[] buffer = new byte[3];
stream.read(buffer, 0, 3);
codes.add(buffer);
}
}
当我在文件中只保存一个对象时，它工作得很好。当我尝试保存更多时，阅读不起作用（它会抛出一个StreamCorruptedException）。它在 while 循环中只读取一个对象！
在主类中，我只使用了两个简单的方法：
// WRITE TO FILE
logInfo.writeLog();
// READ FROM FILE
ArrayList<LogInfo> logInfoArrayList = logInfo.readLog();
定义为：
public void writeLog()
{
File file = new File (Environment.getExternalStorageDirectory().getAbsolutePath(), "data.log");
FileOutputStream fos;
try {
fos = new FileOutputStream(file, true);
//fos = openFileOutput(Environment.getExternalStorageDirectory().getAbsolutePath() + "/data.log", Context.MODE_APPEND);
ObjectOutputStream os = new ObjectOutputStream(fos);
os.writeObject(this);
os.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public ArrayList<LogInfo> readLog()
{
ArrayList<LogInfo> logInfoArray = new ArrayList<LogInfo>();
try{
File file = new File (Environment.getExternalStorageDirectory().getAbsolutePath(), "data.log");
FileInputStream fis = new FileInputStream(file);
ObjectInputStream reader = new ObjectInputStream(fis);
LogInfo tempLogInfo = new LogInfo();
while((tempLogInfo = (LogInfo)reader.readObject()) != null)
logInfoArray.add(tempLogInfo);
reader.close();
} catch (Exception e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
return logInfoArray;
}
要求更新：
//We use this class to not write a header in a file that already exist
class MyObjectOutputStream extends ObjectOutputStream {
public MyObjectOutputStream(OutputStream os) throws IOException {
super(os);
}
@Override
protected void writeStreamHeader() {}
}