我有一个Android应用程序,我想读写ArrayList<MyClass>
到内部存储。
写作部分有效(我相信,尚未测试过:-)):
ArrayList<MyClass> aList;
public void saveToInternalStorage() {
try {
FileOutputStream fos = ctx.openFileOutput(STORAGE_FILENAME, Context.MODE_PRIVATE);
fos.write(aList.toString().getBytes());
fos.close();
}
catch (Exception e) {
Log.e("InternalStorage", e.getMessage());
}
}
但我现在要做的是从存储中读取整个ArrayList并将其作为ArrayList返回,如下所示:
public ArrayList<MyClass> readFromInternalStorage() {
ArrayList<MyClass> toReturn;
FileInputStream fis;
try {
fis = ctx.openFileInput(STORAGE_FILENAME);
//read in the ArrayList
toReturn = whatever is read in...
fis.close();
} catch (FileNotFoundException e) {
Log.e("InternalStorage", e.getMessage());
} catch (IOException e) {
Log.e("InternalStorage", e.getMessage());
}
return toReturn
}
我以前从未在Android文件中读过,所以我不知道这是否可能。
但是我可以通过我的自定义ArrayList
阅读一种方式吗?
答案 0 :(得分:5)
你必须序列化/反序列化你的对象:
你的MyClass必须使用Serializable,MyClass中的所有成员都必须是可序列化的
public void saveToInternalStorage() {
try {
FileOutputStream fos = ctx.openFileOutput(STORAGE_FILENAME, Context.MODE_PRIVATE);
ObjectOutputStream of = new ObjectOutputStream(fos);
of.writeObject(aList);
of.flush();
of.close();
fos.close();
}
catch (Exception e) {
Log.e("InternalStorage", e.getMessage());
}
}
反序列化对象:
public ArrayList<MyClass> readFromInternalStorage() {
ArrayList<MyClass> toReturn;
FileInputStream fis;
try {
fis = ctx.openFileInput(STORAGE_FILENAME);
ObjectInputStream oi = new ObjectInputStream(fis);
toReturn = oi.readObject();
oi.close();
} catch (FileNotFoundException e) {
Log.e("InternalStorage", e.getMessage());
} catch (IOException e) {
Log.e("InternalStorage", e.getMessage());
}
return toReturn
}