Question

我的ListView正确填充，但由于某些原因，添加和删除是古怪的，并且无法正常工作！我做错了吗？

在OnCreate（）

中进行设置

listView = (ListView) findViewById(R.id.ListView);

        registerForContextMenu(listView); 

        deserializeQuotes();

        if(quotes == null || quotes.size() == 0){
            quotes = new ArrayList<Quote>();
            //populateDefaultQuotes();
            //serializeQuotes();
            //getQuotesFromYQL();
        }

        this.quotesAdapter = new QuoteAdapter(this, R.layout.mainrow, quotes);
        listView.setAdapter(this.quotesAdapter);

        listView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id) {
                deserializeQuotes();
                Quote myQuote = quotes.get(position);
                Toast toast = Toast.makeText(getApplicationContext(), myQuote.getName(), Toast.LENGTH_SHORT);
                toast.show();
            }
        });

引用适配器私有类

private class QuoteAdapter extends ArrayAdapter<Quote> {

        private ArrayList<Quote> items;

        public QuoteAdapter(Context context, int textViewResourceId,
                ArrayList<Quote> items) {
            super(context, textViewResourceId, items);
            this.items = items;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View v = convertView;
            if (v == null) {
                LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                v = vi.inflate(R.layout.mainrow, null);
            }
            Quote q = items.get(position);
            if (q != null) {
                TextView nameText = (TextView) v.findViewById(R.id.nameText);
                TextView priceText = (TextView) v.findViewById(R.id.priceText);
                TextView changeText = (TextView) v.findViewById(R.id.changeText);

                if (nameText != null) {
                    nameText.setText(q.getSymbol());
                }
                if (priceText != null) {
                    priceText.setText(q.getLastTradePriceOnly());
                }
                if (changeText != null) {
                    changeText.setText(q.getChange());
                }
            }
            return v;
        }
    }

从列表中删除项目（此操作无效）

@Override  
    public boolean onContextItemSelected(MenuItem item) {  
        if(item.getTitle()=="Remove"){
            deserializeQuotes();
            AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
            quotesAdapter.remove(quotes.get(info.position));
            quotesAdapter.notifyDataSetChanged();
            serializeQuotes();
        }  
        else {
            return false;
        }  

        return true;  
    }

将项目添加到列表中（此工作）

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        deserializeQuotes();
        this.quotesAdapter = new QuoteAdapter(this, R.layout.mainrow, quotes);      
        quotesAdapter.notifyDataSetChanged();
        listView.setAdapter(quotesAdapter);
    }
}

以下是我序列化和反序列化的方法

private void serializeQuotes(){
        FileOutputStream fos;
        try {
            fos = openFileOutput(Constants.FILENAME, Context.MODE_PRIVATE);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(quotes); 
            oos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }
    }

    @SuppressWarnings("unchecked")
    private void deserializeQuotes(){
        try{
            FileInputStream fis = openFileInput(Constants.FILENAME);
            ObjectInputStream ois = new ObjectInputStream(fis);
            quotes = (ArrayList<Quote>) ois.readObject();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }catch(ClassNotFoundException e){
            e.printStackTrace();
        }
    }

Answer 1

代码似乎没问题。您可以尝试在删除中使用此功能吗？：

if("Remove".equals(item.getTitle())) {
   //....
}

修改

我刚刚注意到你通过调用deserializeQuotes()来反序列化“Quote”对象。你是否覆盖了Quote对象的boolean equals(Object)方法？反序列化时，创建的对象不是“相同的”，即它们完全是新对象，如果你没有覆盖equals方法：

quotesAdapter.remove(quotes.get(info.position));

将失败，因为它不会在列表中找到要删除的任何Quote对象。

你能检查一下吗？

我是否正确创建自定义ArrayAdapter？

1 个答案: