Question

我将设备列表添加到ArrayAdapter并在ListView中显示，其中设备列表来自蓝牙扫描，扫描的设备首先添加到arrayadapter。然后我将它添加到列表视图中以向用户显示扫描的蓝牙设备列表。

但是当我扫描设备时，重复的设备正在添加，假设设备A扫描意味着再次显示设备A两到三次。我想只显示一次扫描设备列表。如何实现它。对不起，如果问题含糊不清。

以下代码用于查询新设备并将其添加到arrayadapter：

if (BluetoothDevice.ACTION_FOUND.equals(action))
        {
            // Get the BluetoothDevice object from the Intent
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            // If it's already paired, skip it, because it's been listed already
            if (device.getBondState() != BluetoothDevice.BOND_BONDED)
            {
                mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
            }
        // When discovery is finished, change the Activity title
        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
            setProgressBarIndeterminateVisibility(false);
            setTitle(R.string.select_device);
            if (mNewDevicesArrayAdapter.getCount() == 0) {
                String noDevices = getResources().getText(R.string.none_found).toString();
                mNewDevicesArrayAdapter.add(noDevices);
            }
        }

它是4.1版Android示例中的程序，示例名称为Bluetooth Chat。活动的地点为DeviceListActivityScan.java。

Answer 1

我在两部手机中运行此演示，只有一部分会扫描多次。所以我猜这与设备有关。

你可以做到这一点来避免它：

            if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
                String deviceInfo = device.getName() + "\n" + device.getAddress();
                if(mNewDevicesArrayAdapter.getPosition(deviceInfo) < 0) {
                    mNewDevicesArrayAdapter.add(deviceInfo);
                }
            }

Answer 2

这是一个用于显示蓝牙设备及其信号强度的I类存储。

由于RSSI值经常更新，它会检查蓝牙设备是否已存在于public class DeviceListAdapter extends ArrayAdapter<String> { private static class ViewHolder { ImageView signalImage; TextView deviceName; TextView deviceAddress; } private LayoutInflater mInflator; // for each BLE device address store the RSSI value and name private Map<String, Integer> mRssi = new HashMap<String, Integer>(); private Map<String, String> mName = new HashMap<String, String>(); public DeviceListAdapter(Context context) { super(context, R.layout.rowlayout); mInflator = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); } public void addDevice(String address, String name, int rssi) { if (mRssi.put(address, rssi) == null) { // add a new BLE device to the List add(address); mName.put(address, name); } else { // just refresh the List after updating RSSI value notifyDataSetChanged(); } } // return bitmap resource id for a signal strength private int rssi2res(int rssi) { if (rssi < -100) return R.drawable.signal1; if (rssi < -75) return R.drawable.signal2; if (rssi < -50) return R.drawable.signal3; return R.drawable.signal4; } @Override public View getView(int i, View view, ViewGroup viewGroup) { ViewHolder viewHolder; // General ListView optimization code. if (view == null) { view = mInflator.inflate(R.layout.rowlayout, viewGroup, false); viewHolder = new ViewHolder(); viewHolder.signalImage = (ImageView) view.findViewById(R.id.signalImage); viewHolder.deviceAddress = (TextView) view.findViewById(R.id.deviceAddress); viewHolder.deviceName = (TextView) view.findViewById(R.id.deviceName); view.setTag(viewHolder); } else { viewHolder = (ViewHolder) view.getTag(); } String address = getItem(i); int rssi = mRssi.get(address); viewHolder.signalImage.setImageResource(rssi2res(rssi)); String name = mName.get(address); viewHolder.deviceName.setText(name); viewHolder.deviceAddress.setText(address); return view; } }方法中的列表中 - 并且仅在这种情况下更新RSSI值：

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如何在ArrayAdapter <string> </string>中标识现有项目

2 个答案: