如何避免在Android上的onCreate上重新创建视图？

这是我的onCreate方法：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_human_list);

    if (findViewById(R.id.human_detail_container) != null) {
        // The detail container view will be present only in the
        // large-screen layouts (res/values-large and
        // res/values-sw600dp). If this view is present,then the
        // activity should be in two-pane mode.
        mTwoPane = true;

        // In two-pane mode,list items should be given the
        // 'activated' state when touched.
        ((HumanListFragment) getSupportFragmentManager()
                .findFragmentById(R.id.human_list))
                .setActivateOnItemClick(true);
    }

    if (savedInstanceState == null || !savedInstanceState.getBoolean("displayed_contacts"))
        displayContacts();
}

我的onSaveInstanceState：

@Override
protected void onSaveInstanceState(Bundle savedInstanceState) {
    super.onSaveInstanceState(savedInstanceState);
    savedInstanceState.putBoolean("displayed_contacts",true);
}

而且我不确定这是否相关,但这是我的displayContacts以防万一：

private void displayContacts() {

    // Init variables
    String[] SelectColumns = new String[] { Contacts._ID,Contacts.disPLAY_NAME_PRIMARY,Contacts.PHOTO_URI };
    String rawContactID,displayName,phoneNumber;
    InputStream thumbnailPhoto;
    Cursor c,infoC;

    // Outer cursor (fetches all contact IDs)
    c = getContentResolver().query(
            Contacts.CONTENT_URI,SelectColumns,Contacts.HAS_PHONE_NUMBER + " = 1 ",null,Contacts.disPLAY_NAME_PRIMARY);

    Log.v(getPackageName(),"Found " + (c != null ? c.getCount() : "0") + " contacts");
    try {
        if (c.movetoFirst()) {
            do {
                // Columns
                rawContactID    = c.getString(c.getColumnIndex(SelectColumns[0]));
                displayName     = c.getString(c.getColumnIndex(SelectColumns[1]));
                String[] selectPhone = {CommonDataKinds.Phone.NUMBER};

                thumbnailPhoto = openThumbnail(Long.valueOf(rawContactID));

                infoC = getContentResolver().query(
                        CommonDataKinds.Phone.CONTENT_URI,selectPhone,CommonDataKinds.Phone.CONTACT_ID + " = ?",new String[] {rawContactID},null
                    );
                infoC.movetoFirst();
                phoneNumber = infoC.getString(0);

                // Adds items to ListView
                HumanContent.addItem(new HumanContent.HumanItem(rawContactID,phoneNumber != "n/a" ? phoneNumber : "",thumbnailPhoto));
                Log.v(getPackageName(),"Cursor position: " + c.getPosition() + ",contact ID: " + rawContactID);
                infoC.close();
            } while (c.movetoNext());
            c.close();
        }
        displayed_contacts = true;
    } catch (Exception e) {
        Log.e(getPackageName(),e.getMessage());
    }
}

现在是这样的：

当我使用后退键退出应用程序,然后通过图标再次打开它时;即使列表保存在内存中,列表也会重新创建：所以我在同一视图中获得了一个双重联系人列表.

在这种情况下,savedInstanceState为null,因此达到了if条件,但实际上该视图已经有了我之前的联系人列表.是什么赋予了？如何避免重新创建列表？我已经尝试过使用实例变量,但无济于事.

我还想避免100％重复列表 – 如果我可以重用现有的视图,真棒.