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我试图建立一个android应用程序，扫描蓝牙设备并将它们添加到recyclerview。当我尝试清除我的ArrayList并在适配器中向它添加新数据时，我最终得到了一个空数组列表。当我不清除列表我结束了一个包含每个设备两次这样的列表：[**:71:9F:B6:59:**, **:71:9F:B6:59:**]在logcat中。我也认为我在这里用我的notifydatasetchanged调用做错了什么，因为我的recyclerview中没有任何显示。我敢肯定，这是简单的，我失踪，但我不能看到它。我发布了我的主要活动的代码以及我的recyclerview.adapter，希望有人能够向我指出问题。提前致谢。这是我的主要活动：这是写在科特林不是Java的找到重复的蓝牙设备。我在这里双重浸泡？也能够更新recyclerview
public class ToofActivity extends AppCompatActivity implements CompoundButton.OnCheckedChangeListener {
private static final String TAG = "ToofActivity";
private static final int REQUEST_COARSE_LOCATION = 222;
private static BluetoothAdapter btAdapter;
private TextView mStatusLabel;
private Switch mStatusSwitch;
private ProgressBar mProgressBar;
private RecyclerView mDeviceRecylcer;
private static ArrayList<BluetoothDevice> mDevices = new ArrayList<>();
private DeviceAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_toof);
checkLocationPermission();
btAdapter = BluetoothAdapter.getDefaultAdapter();
mStatusLabel = (TextView) findViewById(R.id.status_view);
mStatusSwitch = (Switch) findViewById(R.id.status_switch);
mStatusSwitch.setChecked(btAdapter.isEnabled());
mStatusSwitch.setOnCheckedChangeListener(this);
mProgressBar = (ProgressBar) findViewById(R.id.search_progress_bar);
mDeviceRecylcer = (RecyclerView) findViewById(R.id.device_recycler);
mDeviceRecylcer.setLayoutManager(new LinearLayoutManager(this));
mAdapter = new DeviceAdapter(mDevices, getApplicationContext());
mDeviceRecylcer.setAdapter(mAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.options_menu, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.searchOption:
DiscoveryTask discovery = new DiscoveryTask(btAdapter, this, mDevices, mProgressBar);
discovery.setOnCompleteListener(new DiscoveryTask.OnCompletedListener() {
@Override
public void onComplete() {
Log.d(TAG, "devices found : " + mDevices.toString());
mAdapter.updateItems(mDevices);
}
});
discovery.execute((Void) null);
break;
}
return true;
}
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
btAdapter.enable();
mStatusLabel.setText("Active");
} else {
btAdapter.disable();
mStatusLabel.setText("Inactive");
}
}
public static void setDeviceList(ArrayList<BluetoothDevice> deviceList) {
mDevices = deviceList;
}
protected void checkLocationPermission() {
if (this.checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
REQUEST_COARSE_LOCATION);
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case REQUEST_COARSE_LOCATION: {
if (grantResults.length <= 0
|| grantResults[0] != PackageManager.PERMISSION_GRANTED) {
checkLocationPermission();
break;
}
}
}
}
}
，也是我的适配器类：
class DeviceAdapter(val mDevices: ArrayList<BluetoothDevice>, val mContext : Context) : RecyclerView.Adapter<DeviceAdapter.DeviceHolder>(){
fun updateItems(list: ArrayList<BluetoothDevice>){
//mDevices.clear()
mDevices.addAll(list)
Log.d(TAG, "updating items : $mDevices")
notifyDataSetChanged()
}
override fun onBindViewHolder(holder: DeviceHolder, position: Int) {
holder.bindItems(mDevices.get(position))
}
override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): DeviceHolder?{ //return is not to be NULL!
val v = LayoutInflater.from(mContext).inflate(R.layout.device_item, parent, false)
return DeviceHolder(v)
}
override fun getItemCount(): Int {
return mDevices.size
}
inner class DeviceHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val nameView = itemView.findViewById(R.id.nameView) as TextView
val addrView = itemView.findViewById(R.id.addressView) as TextView
fun bindItems(btDevice: BluetoothDevice){
nameView.text = btDevice.name
addrView.text = btDevice.address
}
}
companion object {
val TAG = "DeviceAdapter"
}
}