Java 如何在listview中保存二维码扫描结果？

在条形码部分，我阅读了条形码。我想将扫描结果保存到我创建的列表视图中。我试着通过看很多项目来做到这一点，但我失败了。你能帮助我吗？如果问题有点长，我很抱歉

public class BarcodeReaderFragment extends Fragment {

barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
    @Override
    public void release() {

    }

    @Override
    public void receiveDetections(Detector.Detections<Barcode> detections) {
        final SparseArray<Barcode> qrcode = detections.getDetectedItems();
        if (qrcode.size() != 0) {
            Intent my = new Intent(getActivity(),ResultActivity.class);
            my.putExtra("type", qrcode.valueAt(0));

            currentTime = Calendar.getInstance().getTime();
            df = new SimpleDateFormat("dd-MMM-yyyy");
            String formattedDate = df.format(currentTime);
            String d = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(Calendar.getInstance().getTime());
            System.out.println(formattedDate);

            //Add QR scan result to listview???
            //Add current time and date to listview???

            Gson gson = new Gson();
            String json = gson.toJson(qrcode.valueAt(0));
            SharedPreferences sp = getActivity().getSharedPreferences("list",Context.MODE_PRIVATE);
            addhistory(sp,json);
            startActivity(my);
            getActivity().finish();
            barcodeDetector.release();
        }
    }
});

public void addhistory(SharedPreferences sp,String json){
    int x = sp.getInt("index",0);
    SharedPreferences.Editor editor = sp.edit();
    editor.putString(String.valueOf(x),json);
    int  y;
    y = x+1;
    editor.putInt("index",y);
    editor.commit();

}

ListView\u适配器

public class ListView_Adapter extends BaseAdapter {

    private Context context;
    private ArrayList<Item_Model> item_modelArrayList;
    private SparseBooleanArray mSelectedItemsIds;

    public ListView_Adapter(Context context, ArrayList<Item_Model> item_modelArrayList) {
        this.context = context;
        this.item_modelArrayList = item_modelArrayList;
        mSelectedItemsIds = new SparseBooleanArray();
    }

    @Override
    public int getCount() {
        return item_modelArrayList.size();
    }

    @Override
        public Item_Model getItem(int position) {
        return item_modelArrayList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
        public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        ViewHolder holder;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item_row, parent, false);
            holder = new ViewHolder();
            holder.Result = (TextView) convertView.findViewById(R.id.result);
            holder.Date_time = (TextView) convertView.findViewById(R.id.date_time);

            convertView.setTag(holder);
        } else
            holder = (ViewHolder) convertView.getTag();

        holder.Result.setText(item_modelArrayList.get(position).getResult());
    holder.Date_time.setText(item_modelArrayList.get(position).getDate_time());


        /** Change background color of the selected items in list view  **/
        convertView
            .setBackgroundColor(mSelectedItemsIds.get(position) ? 0x48FF9800
                    : Color.TRANSPARENT);

        return convertView;
    }

    private class ViewHolder {
        TextView Result, Date_time;
    }

公共类ListView\u适配器扩展了BaseAdapter{
私人语境；
私有ArrayList项_modelArrayList；
专用SparseBooleanArray MSelectEditEMSID；
公共ListView_适配器（上下文上下文，ArrayList项_modelArrayList）{
this.context=上下文；
this.item_modelArrayList=item_modelArrayList；
mSelectedItemsIds=new SparseBooleanArray（）；
}
@凌驾
public int getCount（）{
返回项_modelArrayList.size（）；
}
@凌驾
公共项目\模型getItem（内部位置）{
返回项目_modelArrayList.get（位置）；
}
@凌驾
公共长getItemId（int位置）{
返回位置；
}
@凌驾
公共视图getView（int位置、视图转换视图、视图组父视图）{
LayoutFlater充气器=（LayoutFlater）context.getSystemService（context.LAYOUT\u充气器\u服务）；
视窗座；
if（convertView==null）{
convertView=充气机。充气（R.layout.item_行，父项，false）；
holder=新的ViewHolder（）；
holder.Result=（TextView）convertView.findViewById（R.id.Result）；
holder.Date\u time=（TextView）convertView.findViewById（R.id.Date\u time）；
convertView.setTag（支架）；
}否则
holder=（ViewHolder）convertView.getTag（）；
holder.Result.setText（item_modelArrayList.get（position.getResult（））；
holder.Date\u time.setText（item\u modelArrayList.get（position.getDate\u time（））；
/**更改列表视图中选定项目的背景色**/
convertView
.setBackgroundColor（mSelectedItemsIds.get（位置）？0x48FF9800
：颜色（透明）；
返回视图；
}
私有类视窗持有者{
文本查看结果、日期和时间；
}

ThreeFragment在本集中，我正在观看Listview

private ActionMode mActionMode;

private static View view;
private static ListView_Adapter adapter;
private static ListView listView;
//Action Mode for toolbar

private static ArrayList<Item_Model> item_models;

public ThreeFragment() {
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.fragment_three, container, false);
    populateListView();
    implementListViewClickListeners();




    return view;
}





//I don't know how to fill this section with detector results?
//Populate ListView with dummy data
private void populateListView() {
    listView = (ListView) view.findViewById(R.id.list_view);
    item_models = new ArrayList<>();
    for (int i = 1; i <= 40; i++)
        item_models.add(new Item_Model("Result " + i, "Date-Time " + i));


    adapter = new ListView_Adapter(getActivity(), item_models);
    listView.setAdapter(adapter);
    adapter.notifyDataSetChanged();

}


//Implement item click and long click over listview
private void implementListViewClickListeners() {
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //If ActionMode not null select item
            if (mActionMode != null)
                onListItemSelect(position);
        }
    });
    listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
            //Select item on long click
            onListItemSelect(position);
            return true;
        }
    });
}

//List item select method
private void onListItemSelect(int position) {
    adapter.toggleSelection(position);//Toggle the selection

    boolean hasCheckedItems = adapter.getSelectedCount() > 0;//Check if any items are already selected or not

    if (hasCheckedItems && mActionMode == null)
        // there are some selected items, start the actionMode
        mActionMode = ((AppCompatActivity) getActivity()).startSupportActionMode(new Toolbar_ActionMode_Callback(getActivity(),adapter, item_models, true));
    else if (!hasCheckedItems && mActionMode != null)
        // there no selected items, finish the actionMode
        mActionMode.finish();

    if (mActionMode != null)
        //set action mode title on item selection
        mActionMode.setTitle(String.valueOf(adapter
                .getSelectedCount()) + " selected");


}

//Set action mode null after use
public void setNullToActionMode() {
    if (mActionMode != null)
        mActionMode = null;
}


//Delete selected rows
public void deleteRows() {
    SparseBooleanArray selected = adapter
            .getSelectedIds();//Get selected ids

    //Loop all selected ids
    for (int i = (selected.size() - 1); i >= 0; i--) {
        if (selected.valueAt(i)) {
            //If current id is selected remove the item via key
            item_models.remove(selected.keyAt(i));
            adapter.notifyDataSetChanged();//notify adapter

        }
    }
    Toast.makeText(getActivity(), selected.size() + " item deleted.", Toast.LENGTH_SHORT).show();//Show Toast
    mActionMode.finish();//Finish action mode after use

}

private ActionMode mActionMode；
私有静态视图；
专用静态ListView_适配器；
私有静态ListView ListView；
//工具栏的操作模式
私有静态ArrayList项_模型；
公共服务{
}
@可空
@凌驾
CreateView上的公共视图（布局、充气机、视图组容器、捆绑包保存状态）{
视图=充气机。充气（R.layout.fragment_three，容器，假）；
populateListView（）；
实现ListViewClickListeners（）；
返回视图；
}
//我不知道如何用检测器结果填充这一部分？
//用虚拟数据填充ListView
私有void populateListView（）{
listView=（listView）view.findViewById（R.id.list\u视图）；
item_models=新的ArrayList（）；
for（int i=1；i父项、视图、int位置、长id）{
//长按选择项目
onListItemSelect（位置）；
返回true；
}
});
}
//列表项选择方法
私有void onListItemSelect（内部位置）{
adapter.toggleSelection（位置）；//切换选择
boolean hasCheckedItems=adapter.getSelectedCount（）>0；//检查是否已选择任何项
if（hasCheckedItems&&mActionMode==null）
//有一些选定的项目，请启动actionMode
mActionMode=（（AppCompatActivity）getActivity（））.startSupportActionMode（新工具栏\u操作模式\u回调（getActivity（），适配器，项\u模型，true））；
如果（！hasCheckedItems&&mActionMode！=null），则为else
//如果没有选定的项目，请完成操作模式
mActionMode.finish（）；
if（mActionMode！=null）
//在项目选择上设置操作模式标题
mActionMode.setTitle（字符串.valueOf（适配器
.getSelectedCount（））+“selected”）；
}
//使用后将操作模式设置为空
public void setNullToActionMode（）{
if（mActionMode！=null）
mActionMode=null；
}
//删除所选行
公共void deleteRows（）{
SparseBooleanArray selected=适配器
.getSelectedIds（）；//获取所选ID
//循环所有选定的ID
对于（int i=（selected.size（）-1）；i>=0；i--）{
如果（选定。值位于（i））{
//如果选择了当前id，则通过键删除该项目
项目_模型。移除（选定。键入（i））；
adapter.notifyDataSetChanged（）；//通知适配器
}
}
Toast.makeText（getActivity（），selected.size（）+“item deleted.”，Toast.LENGTH_SHORT.show（）；//show Toast
mActionMode.finish（）；//使用后完成操作模式
}

尝试按以下步骤实施：

将

结果活动保持为登录/父活动

将

ThreeFragment

添加到

ResultActivity

创建一个

BarcodeReaderActivity

并直接在此活动中使用

BarcodeDetector

（为了简单起见，请删除

BarcodeReaderFragment

）

使用首选交互上的

startActivityForResult（）

从

ThreeFragment

启动

BarcodeReaderActivity

当您将从

BarcodeDetector

获取结果时，然后使用

setResult（“xxxxxx”）

和

finish（）

活动将结果设置为

BarcodeReaderActivity

在

ThreeFragment

中，您将在

onActivityResult（）中获得结果

获得结果后，将其放入

列表

，并将列表发送到

适配器

和

notifyDataSetChanged（）

更新 很抱歉，我无法更改整个项目导航，这将花费我太多的时间。你应该在这里提出一个精确的问题。我刚刚检查了你的项目并给出了一些反馈。你必须自己编写代码<

private ActionMode mActionMode;

private static View view;
private static ListView_Adapter adapter;
private static ListView listView;
//Action Mode for toolbar

private static ArrayList<Item_Model> item_models;

public ThreeFragment() {
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.fragment_three, container, false);
    populateListView();
    implementListViewClickListeners();




    return view;
}





//I don't know how to fill this section with detector results?
//Populate ListView with dummy data
private void populateListView() {
    listView = (ListView) view.findViewById(R.id.list_view);
    item_models = new ArrayList<>();
    for (int i = 1; i <= 40; i++)
        item_models.add(new Item_Model("Result " + i, "Date-Time " + i));


    adapter = new ListView_Adapter(getActivity(), item_models);
    listView.setAdapter(adapter);
    adapter.notifyDataSetChanged();

}


//Implement item click and long click over listview
private void implementListViewClickListeners() {
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //If ActionMode not null select item
            if (mActionMode != null)
                onListItemSelect(position);
        }
    });
    listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
            //Select item on long click
            onListItemSelect(position);
            return true;
        }
    });
}

//List item select method
private void onListItemSelect(int position) {
    adapter.toggleSelection(position);//Toggle the selection

    boolean hasCheckedItems = adapter.getSelectedCount() > 0;//Check if any items are already selected or not

    if (hasCheckedItems && mActionMode == null)
        // there are some selected items, start the actionMode
        mActionMode = ((AppCompatActivity) getActivity()).startSupportActionMode(new Toolbar_ActionMode_Callback(getActivity(),adapter, item_models, true));
    else if (!hasCheckedItems && mActionMode != null)
        // there no selected items, finish the actionMode
        mActionMode.finish();

    if (mActionMode != null)
        //set action mode title on item selection
        mActionMode.setTitle(String.valueOf(adapter
                .getSelectedCount()) + " selected");


}

//Set action mode null after use
public void setNullToActionMode() {
    if (mActionMode != null)
        mActionMode = null;
}


//Delete selected rows
public void deleteRows() {
    SparseBooleanArray selected = adapter
            .getSelectedIds();//Get selected ids

    //Loop all selected ids
    for (int i = (selected.size() - 1); i >= 0; i--) {
        if (selected.valueAt(i)) {
            //If current id is selected remove the item via key
            item_models.remove(selected.keyAt(i));
            adapter.notifyDataSetChanged();//notify adapter

        }
    }
    Toast.makeText(getActivity(), selected.size() + " item deleted.", Toast.LENGTH_SHORT).show();//Show Toast
    mActionMode.finish();//Finish action mode after use

}

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    if (isVisibleToUser && isResumed()) {
        //this fragment is visible now, do your expected code here
    } else {
        //this fragment is not visible now, do your expected code here
    }
}

@Override
public void onResume() {
    super.onResume();
    if(getUserVisibleHint()){
        //this fragment is visible now, do your expected code here
    } else {
        //this fragment is not visible now, do your expected code here
    }
}