我正在使用 DeviceListActivity 来发现蓝牙设备。这是 Android 蓝牙聊天程序示例中使用的 Activity。
我在虚拟机上运行该程序。
问题:当我开始扫描/发现蓝牙设备时:
它列出了重复的设备名称:
我有一台可发现的设备,但程序多次列出它。
如何防止列出重复的设备名称?
活动代码:
package com.example.android.BluetoothChat;
import java.util.Set;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
/**
* This Activity appears as a dialog. It lists any paired devices and
* devices detected in the area after discovery. When a device is chosen
* by the user, the MAC address of the device is sent back to the parent
* Activity in the result Intent.
*/
public class DeviceListActivity extends Activity {
// Debugging
private static final String TAG = "DeviceListActivity";
private static final boolean D = true;
// Return Intent extra
public static String EXTRA_DEVICE_ADDRESS = "device_address";
// Member fields
private BluetoothAdapter mBtAdapter;
private ArrayAdapter<String> mPairedDevicesArrayAdapter;
private ArrayAdapter<String> mNewDevicesArrayAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Setup the window
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.device_list);
// Set result CANCELED incase the user backs out
setResult(Activity.RESULT_CANCELED);
// Initialize the button to perform device discovery
Button scanButton = (Button) findViewById(R.id.button_scan);
scanButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
doDiscovery();
v.setVisibility(View.GONE);
}
});
// Initialize array adapters. One for already paired devices and
// one for newly discovered devices
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
// Find and set up the ListView for paired devices
ListView pairedListView = (ListView) findViewById(R.id.paired_devices);
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
pairedListView.setOnItemClickListener(mDeviceClickListener);
// Find and set up the ListView for newly discovered devices
ListView newDevicesListView = (ListView) findViewById(R.id.new_devices);
newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
newDevicesListView.setOnItemClickListener(mDeviceClickListener);
// Register for broadcasts when a device is discovered
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(mReceiver, filter);
// Register for broadcasts when discovery has finished
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(mReceiver, filter);
// Get the local Bluetooth adapter
mBtAdapter = BluetoothAdapter.getDefaultAdapter();
// Get a set of currently paired devices
Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();
// If there are paired devices, add each one to the ArrayAdapter
if (pairedDevices.size() > 0) {
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
for (BluetoothDevice device : pairedDevices) {
mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
} else {
String noDevices = getResources().getText(R.string.none_paired).toString();
mPairedDevicesArrayAdapter.add(noDevices);
}
}
@Override
protected void onDestroy() {
super.onDestroy();
// Make sure we're not doing discovery anymore
if (mBtAdapter != null) {
mBtAdapter.cancelDiscovery();
}
// Unregister broadcast listeners
this.unregisterReceiver(mReceiver);
}
/**
* Start device discover with the BluetoothAdapter
*/
private void doDiscovery() {
if (D) Log.d(TAG, "doDiscovery()");
// Indicate scanning in the title
setProgressBarIndeterminateVisibility(true);
setTitle(R.string.scanning);
// Turn on sub-title for new devices
findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);
// If we're already discovering, stop it
if (mBtAdapter.isDiscovering()) {
mBtAdapter.cancelDiscovery();
}
// Request discover from BluetoothAdapter
mBtAdapter.startDiscovery();
}
// The on-click listener for all devices in the ListViews
private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
// Cancel discovery because it's costly and we're about to connect
mBtAdapter.cancelDiscovery();
// Get the device MAC address, which is the last 17 chars in the View
String info = ((TextView) v).getText().toString();
String address = info.substring(info.length() - 17);
// Create the result Intent and include the MAC address
Intent intent = new Intent();
intent.putExtra(EXTRA_DEVICE_ADDRESS, address);
// Set result and finish this Activity
setResult(Activity.RESULT_OK, intent);
finish();
}
};
// The BroadcastReceiver that listens for discovered devices and
// changes the title when discovery is finished
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// When discovery finds a device
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);
}
}
}
};
}
编辑: 这个问题在我的真实设备(智能手机)上消失了。我不知道为什么模拟器会出现这样的问题!
简单。要过滤,请使用
Set
。
HashSet
在
HashSet
上添加蓝牙地址并用方法contains()
验证。
如果
contains()
返回false
,则将蓝牙数据添加到列表中
如果
contains()
返回 true
,则不要将蓝牙数据添加到列表中
将其写在你内心ACTION_FOUND。
if (mNewDevicesArrayAdapter.size() < 1) {
mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
mNewDevicesArrayAdapter.notifyDataSetChanged();
}
else {
boolean flag = true; // flag to indicate that particular device is already in the arlist or not
for(int i = 0; i<mNewDevicesArrayAdapter.size();i++)
{
if(device.getAddress().equals(mNewDevicesArrayAdapter.get(i).getAddress()))
{
flag = false;
}
}
if(flag == true)
{
mNewDevicesArrayAdapter.add(device.getName()+"\n"+device.getAddress());
mNewDevicesArrayAdapter.notifyDataSetChanged();
}
}
这个对我有用
public class MainActivity extends ActionBarActivity {
private ListView listView;
private ArrayList<String> mDeviceList = new ArrayList<String>();
private BluetoothAdapter mBluetoothAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
mBluetoothAdapter.startDiscovery();
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter);
}
@Override
protected void onDestroy() {
unregisterReceiver(mReceiver);
super.onDestroy();
}
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = intent
.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mDeviceList.add(device.getName() + "\n" + device.getAddress());
Log.i("BT", device.getName() + "\n" + device.getAddress());
listView.setAdapter(new ArrayAdapter<String>(context,
android.R.layout.simple_list_item_1, mDeviceList));
}
}
};
在BluetoothDevice.ACTION_FOUND的onReceive中,在将蓝牙设备添加到Arraylist之前,使用ArrayList的contains()方法检查Arraylist是否已包含该设备。 仅当 contains() 返回 false 时才将设备添加到列表中。
Code is as below:
List<BluetoothDevice> availableDevices = new ArrayList<>();
class BluetoothReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action != null) {
switch (action) {
case BluetoothDevice.ACTION_FOUND: {
// Discovery has found a device. Get the BluetoothDevice
// object and its info from the Intent.
BluetoothDevice bluetoothDevice =
intent.getParcelableExtra(BluetoothDevice
.EXTRA_DEVICE);
//Add the device to the list only if contains() returns false.
if (!availableDevices.contains(bluetoothDevice)) {
availableDevices.add(bluetoothDevice);
}
displayAvailableDevices();
break;
}
它对我有用
@Override
public void onDeviceDiscovered(BluetoothDevice device) {
listener.endLoading(true);
devices.contains(device);
//======================To add only unique device not repeating same device in listView========================
if( devices.contains(device)){
}else {
devices.add(device);
}
//======================End of add only unique device not repeating same device in listView====================
notifyDataSetChanged();
}