Android的节约一个ArrayList＆LT;对象＆gt;为共享preference [英] Android saving an ArrayList<Object> as SharedPreference

问题描述

我目前正在试图挽救包含的POJO作为共享preference当用户重新进入应用程序检索它一个ArrayList，但它似乎并没有工作。

I'm currently trying to save an ArrayList containing POJOs as a SharedPreference to retrieve it when the user re-enters the application, but it doesn't seem to work.

这是我做的：

回调方法

ArrayList<myObject> myList;
ArrayList<Boolean> myobject_repeat;
MyListAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.myview);
    lw = (ListView) findViewById(R.id.lw);
    myList= new ArrayList<myObject>();
    myobject_repeat = new ArrayList<Boolean>();
    adapter = new MyListAdapter(this, myList);
    lw.setAdapter(adapter);
}

@Override
protected void onPause() {
    saveArray();
    super.onPause();
}

@Override
protected void onResume() {
    loadArray(this);
    super.onResume();
}

方法保存/载入阵列

Methods to save/load array

public boolean saveArray() {
    SharedPreferences pref = PreferenceManager
            .getDefaultSharedPreferences(this);
    SharedPreferences.Editor edit = pref.edit();
    edit.putInt("list_size", myList.size());

    for (int i = 0; i < myList.size(); i++) {
        edit.remove("id" + i);
        edit.remove("repeat" + i);
        edit.putLong("id" + i, myList.get(i).getId());
        edit.putBoolean("repeat" + i, myList.get(i).isRepeat());
    }

    return edit.commit();
}

public void loadArray(Context c) {
    SharedPreferences pref = PreferenceManager
            .getDefaultSharedPreferences(c);
    myList.clear();
    myList2.clear();
    int listsize = pref.getInt("list_size", 0);

    for (int i = 0; i < listsize; i++) {
        MyObject tmpObject = new MyObject();
        tmpObject.setId(pref.getLong("id" + i, 0));
        tmpObject.setRepeat(pref.getBoolean("repeat" + i, false));
        myList.add(tmpObject);
    }

}

这是我的对象添加到阵列

This is where I add an object to the array

@Override
protected void onActivityResult(int requestCode, int resultCode,
        Intent result) {
    super.onActivityResult(requestCode, resultCode, result);

    if (resultCode == RESULT_OK) {
        int hour = result.getExtras().getInt("hour");
        int minute = result.getExtras().getInt("minute");
        boolean repeat = result.getExtras().getBoolean("repeat");
        setUpObject(hour, minute, repeat);
    }
}

private void setUpObject(int hour, int minute, boolean repeat) {

    //Doing magic tricks

    MyObject tmpObject= new MyObject ();
    tmpObject.setHours(hour);
    tmpObject.setMinutes(minute);
    tmpObject.setRepeat(repeat);
    tmpObject.setId(timeInMs);

    myList.add(tmpObject);
    adapter.remove(tmpObject);
    adapter.add(tmpObject);
    adapter.notifyDataSetChanged();
}

这似乎并没有工作。当我调试它的列表是空的。如果我运行应用程序，而不加载/保存按预期工作方法，但你可以看到，列表不会被共享preferences当用户导航回到我的活动依然存在，因此无法使用。

This does not seem to work. When I debug it the lists are empty. If I run the app without the load/save methods it works as intended but as you can see, the lists wont be persisted in SharedPreferences and therefore not available when the user navigates back to my activity.

在这里任何帮助真的是AP preciated。

Any help here is really appreciated.

马库斯

推荐答案

我在这里找到了这个问题：是的onPause其中的onActivityResult我改写阵列空数组后调用。

I found out the problem here: onPause was called after onActivityResult which overwrite my array with an empty array.

这篇关于Android的节约一个ArrayList＆LT;对象＆gt;为共享preference的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！