Question

所以我有一个自定义的ArrayAdapter，它具有这样定义的getView方法

@Override
    public View getView(final int position, View convertView, final ViewGroup parent) {
        int orderId = getItem(position).getId();
        int menuId = getItem(position).getMenuId();
        int userId = getItem(position).getUserId();
        String status = getItem(position).getStatus();

        LayoutInflater inflater = LayoutInflater.from(activity);
        convertView = inflater.inflate(resource, parent, false);

        TextView idView = convertView.findViewById(R.id.order_id);
        TextView nameView = convertView.findViewById(R.id.item_name);
        TextView userIdView = convertView.findViewById(R.id.user_id);
        TextView statusView = convertView.findViewById(R.id.status_view);
        ImageButton cancelButton = convertView.findViewById(R.id.order_canceled);
        ImageButton orderDoneButton = convertView.findViewById(R.id.order_done);
        cancelButton.setTag(orderId);
        orderDoneButton.setTag(orderId);

        if(status.equals("done"))
            orderDoneButton.setImageResource(android.R.drawable.checkbox_on_background);
        else {
            orderDoneButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    orderRequest.getGenericRequest().setUri("/" + v.getTag() + "?status=done");
                    orderRequest.put();
//                ((ImageButton)v).setImageResource(android.R.drawable.checkbox_on_background);

                    notifyDataSetChanged();
                    // TODO cheating but it works
//                Intent intent = activity.getIntent();
//                intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
//                activity.startActivity(intent);
                }
            });
        }

我的问题是，当我这样调用它并单击OrderDoneButton时，即使我正在调用notifyDataSetChanged()并且看到数据库已更新，我的列表视图也不会自动更新。为什么？
第二个问题是在此方法中，注释了“ Intent”，它以我想要的方式工作，但是我不确定这是否是一个好方法，有什么建议吗？

Answer 1

这里是我平时所做的一些解释

带有适配器的设置视图

private ArrayAdapter<String> arrayAdapter;
private ArrayList<String> listPName = new ArrayList<>();
private void showBluetoothPrinters() {
    arrayAdapter = new ArrayAdapter<String>(mContext, android.R.layout.simple_list_item_1, listPName) {
        @NonNull
        @Override
        public View getView(int position, View convertView, @NotNull ViewGroup parent) {
            View view = super.getView(position, convertView, parent);
            TextView tv = view.findViewById(android.R.id.text1);
            tv.setPadding(padding * 3, 0, padding * 3, 0);
            return view;
        }
    };
    lvPrinter.setAdapter(arrayAdapter);
}

然后在更新一些数据后调用notifyDataSetChanged（）

Set<BluetoothDevice> mPairedDevices = mBluetoothAdapter.getBondedDevices();
                if (mPairedDevices.size() > 0) {
                    for (BluetoothDevice mDevice : mPairedDevices) {
                        listPName.add(mDevice.getName());
                    }
                }
                if (arrayAdapter != null){
                    arrayAdapter.notifyDataSetChanged();
                }

不知道这是否是您的期望

我在适配器中添加了一些代码段调用notifydatasetchage

@Override
public void onBindViewHolder(@NonNull VH holder, int position) {
    int amount = mListData.get(position);
    holder.tvAmount.setText(String.valueOf(amount));
    holder.tvText.setText(decimalFormat.format(amount));

    holder.itemView.setOnClickListener(v -> {
        if (mListener != null){
            mListener.onAmountTapped(amount);
        }
        tempSelected = position;
        notifyDataSetChanged();
    });
    if (position == tempSelected){
        holder.containerView.setBackground(mContext.getResources().getDrawable(R.drawable.rp_shadow_select));
    } else {
        holder.containerView.setBackground(mContext.getResources().getDrawable(R.drawable.rp_shadow));
    }
}

更新数据库后刷新活动或列表视图

1 个答案: